/* style.css */
/* ============================================
   COLOR VARIABLES
   ============================================ */
:root {
    --bg-primary: #1a1a1a;          /* Main page background - very dark gray */
    --bg-secondary: #2d2d2d;        /* Cards, input sections - dark gray */
    --text-primary: #e0e0e0;        /* Main text color - light gray */
    --text-secondary: #b0b0b0;      /* Labels, less important text - medium gray */
    --border-color: #404040;        /* Borders, dividers - medium-dark gray */
    --accent-color: #6BA8F5;        /* Links, highlights - lighter blue for contrast */
    --error-color: #ef5350;         /* Error text - bright red */
    --error-bg: #4a2828;            /* Error backgrounds - dark red */
    --success-color: #66bb6a;       /* Success text - bright green */
    --success-bg: #2a4a2e;          /* Success backgrounds - dark green */
    --input-bg: #2d2d2d;            /* Input field backgrounds - matches secondary */
    --sidebar-width: 350px;         /* Fixed sidebar width on desktop */
    --header-border: #404040;       /* Table header border - matches border color */

    /* Spacing scale */
    --spacing-xs: 0.15rem;          /* 2.4px - micro spacing */
    --spacing-sm: 0.25rem;          /* 4px - small spacing */
    --spacing-md: 0.5rem;           /* 8px - medium spacing */
    --spacing-lg: 0.75rem;          /* 12px - large spacing */
    --spacing-xl: 1rem;             /* 16px - extra large */
    --spacing-2xl: 1.5rem;          /* 24px - 2x extra large */
    --spacing-3xl: 2rem;            /* 32px - 3x extra large */
    --spacing-4xl: 3rem;            /* 48px - 4x extra large */

    /* Color opacity variants */
    --accent-light: rgba(74, 144, 226, 0.05);
    --accent-lighter: rgba(74, 144, 226, 0.1);
    --accent-outline: rgba(74, 144, 226, 0.3);
    --accent-hover: rgba(74, 144, 226, 0.4);
    --accent-faded: rgba(74, 144, 226, 0.8);
    --error-outline: rgba(200, 80, 80, 0.3);
    --error-hover: rgba(200, 80, 80, 0.4);
    --overlay-dark: rgba(0, 0, 0, 0.05);
    --overlay-dark-medium: rgba(0, 0, 0, 0.1);
    --overlay-light: rgba(255, 255, 255, 0.05);
    --overlay-light-medium: rgba(255, 255, 255, 0.8);
}

/* ============================================
   GLOBAL RESET
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    margin: 0;
    padding: 0;
}

/* ============================================
   BODY & LAYOUT
   ============================================ */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    margin: 0;
    padding: 0;
}

.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    height: 100vh;
    width: var(--sidebar-width);
    min-width: 280px;
    max-width: 400px;
    background-color: var(--bg-secondary);
    border-right: 2px solid var(--border-color);
    display: flex;
    flex-direction: column;
    z-index: 100;
}

.nav-header {
    padding: var(--spacing-xl) var(--spacing-xl);
    border-bottom: 1px solid var(--border-color);
    text-align: center;
    flex-shrink: 0;
}

.nav-header h1 {
    font-size: 2rem;
    margin-bottom: var(--spacing-xs);
    letter-spacing: -0.02em;
}

.logo-calc {
    color: var(--text-primary);
    font-weight: 700;
}

.logo-labs {
    color: var(--accent-color);
    font-weight: 700;
}

.nav-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin: 0;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    font-weight: 600;
}

.nav-main {
    flex: 1;
    list-style: none;
    padding: 0 0 var(--spacing-xl) 0;
    overflow-y: auto;
    min-height: 0;
}

.nav-main::-webkit-scrollbar {
    width: 8px;
}

.nav-main::-webkit-scrollbar-track {
    background: transparent;
}

.nav-main::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

.nav-main::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

.nav-bottom {
    list-style: none;
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-xl) 0;
    flex-shrink: 0;
}

.nav-about-inline {
    display: none;
    margin-top: var(--spacing-2xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--border-color);
}

.nav-about-fixed {
    display: block;
}

@media (max-height: 600px) {
    .nav-about-inline {
        display: block;
    }

    .nav-about-fixed {
        display: none;
    }

    .nav-bottom {
        display: none;
    }
}

.sidebar ul li {
    margin: 0;
}

.nav-category {
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-size: 0.75rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-primary);
    margin-top: var(--spacing-2xl);
    background-color: var(--overlay-light);
}

.nav-category:first-child {
    margin-top: 0;
}

.sidebar a {
    display: block;
    padding: 0.875rem var(--spacing-2xl);
    color: var(--text-primary);
    text-decoration: none;
    transition: background-color 0.2s, color 0.2s;
}

.sidebar a .nav-link-title {
    display: block;
    font-weight: 500;
}

.sidebar a .nav-link-desc {
    display: block;
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: var(--spacing-xs);
    line-height: 1.3;
}

.sidebar a:hover {
    background-color: var(--bg-primary);
}

.sidebar a.active {
    background-color: var(--accent-color);
    color: white;
}

.sidebar a.active .nav-link-desc {
    color: var(--overlay-light-medium);
}

.menu-toggle {
    position: absolute;
    left: -9999px;
}

.hamburger {
    display: none;
}

.mobile-title {
    display: none;
}

main {
    margin-left: 280px;
    width: calc(100% - 280px);
    padding: var(--spacing-3xl) var(--spacing-3xl) var(--spacing-3xl) var(--spacing-4xl);
    min-height: 100vh;
}

@media (min-width: 769px) {
    main {
        margin-left: max(280px, var(--sidebar-width));
        width: calc(100% - max(280px, var(--sidebar-width)));
    }
}

main::-webkit-scrollbar {
    width: 12px;
}

main::-webkit-scrollbar-track {
    background: transparent;
}

main::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 6px;
}

main::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

.calculator {
    display: none;
    max-width: 1400px;
    margin: 0;
}

.calculator.active {
    display: block;
}

.calculator h2 {
    margin-bottom: var(--spacing-md);
    color: var(--accent-color);
    font-size: var(--spacing-3xl);
}

.calculator-description {
    margin-bottom: var(--spacing-3xl);
    color: var(--text-secondary);
    font-size: var(--spacing-xl);
}

.usage-guide {
    margin-top: var(--spacing-3xl);
    margin-bottom: var(--spacing-2xl);
}

.usage-guide > h3 {
    margin-bottom: var(--spacing-2xl);
    font-size: 1.3rem;
}

.guide-section {
    margin-bottom: var(--spacing-xl);
    border: 1px solid var(--border-color);
    overflow: visible;
    transition: all 0.3s ease;
}

/* When guide-section is last child in inputs-section, remove extra spacing */
.inputs-section > .guide-section:last-child {
    margin-bottom: 0;
}

.guide-section:hover {
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
}

.guide-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
    padding: 1.25rem var(--spacing-2xl);
    cursor: pointer;
    user-select: none;
    transition: background-color 0.2s ease;
    -webkit-tap-highlight-color: transparent;
}

.guide-header:hover {
    background-color: var(--accent-light);
}

.guide-header:active {
    background-color: var(--accent-lighter);
}

@media (hover: none) {
    .guide-header:hover {
        background-color: transparent;
    }
}

.guide-icon {
    width: 1.75rem;
    height: 1.75rem;
    flex-shrink: 0;
    color: var(--accent-color);
}

.guide-header h4,
.guide-header h3 {
    flex: 1;
    margin: 0;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.guide-toggle {
    width: var(--spacing-2xl);
    height: var(--spacing-2xl);
    color: var(--accent-color);
    transition: transform 0.3s ease;
    flex-shrink: 0;
}

.guide-section.collapsed .guide-toggle {
    transform: rotate(-90deg);
}

.guide-content {
    padding: 0 var(--spacing-2xl) var(--spacing-2xl) 4.25rem;
    max-height: none;
    overflow: visible;
    transition: padding 0.3s ease;
}

.guide-section.collapsed .guide-content {
    display: none;
    padding-top: 0;
    padding-bottom: 0;
}

.guide-content p {
    margin: 0 0 var(--spacing-xl) 0;
    line-height: 1.7;
    color: var(--text-primary);
}

.guide-content p:last-child {
    margin-bottom: 0;
}

.guide-content .guide-section {
    margin-bottom: 0;
    transition: all 0.2s ease;
}

.guide-content .guide-content {
    transition: padding 0.2s ease;
    padding-left: var(--spacing-2xl);
    padding-right: 0;
}

/* Nested guide sections - adjust padding on mobile */
@media (max-width: 768px) {
    .guide-content {
        padding: 0 1rem 1rem 1rem !important;
    }

    .guide-header {
        padding: 1rem !important;
        gap: 0.75rem;
    }

    .guide-content .guide-section {
        margin: 0.75rem 0 0 0;
        width: 100%;
    }

    .guide-content .guide-content {
        padding: 0 0.75rem 0.75rem 0.75rem !important;
    }

    .guide-content .guide-header {
        padding: 0.75rem !important;
        gap: 0.5rem;
    }

    .guide-content p {
        word-wrap: break-word;
        overflow-wrap: break-word;
    }
}

.guide-content ul {
    margin: 0 0 var(--spacing-xl) 0;
    padding-left: 0;
    list-style: none;
}

.guide-content ul:last-child {
    margin-bottom: 0;
}

.guide-content li {
    margin-bottom: var(--spacing-lg);
    line-height: 1.7;
    position: relative;
    padding-left: var(--spacing-2xl);
}

.guide-content li:last-child {
    margin-bottom: 0;
}

.guide-content li::before {
    content: '•';
    position: absolute;
    left: var(--spacing-sm);
    top: 0;
    color: var(--accent-color);
    font-weight: 700;
    font-size: var(--spacing-xl);
    line-height: 1.7;
}

/* Shared two-column grid layout for calculators */
.calculator-layout,
.load-bank-layout {
    display: grid;
    grid-template-columns: 450px 1fr;
    gap: var(--spacing-3xl);
    align-items: start;
    width: 100%;
}

.inputs-section {
    padding: var(--spacing-3xl);
}

/* ============================================
   SHARED UTILITY CLASSES
   ============================================ */

/* Card/Section pattern - shared by multiple components */
.card {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* Section heading pattern - shared accent-colored headers */
.section-heading {
    color: var(--accent-color);
    font-weight: 700;
    margin: var(--spacing-2xl) 0 var(--spacing-md) 0;
}

/* First section heading shouldn't have top margin */
.inputs-section > .section-heading:first-child,
.guide-content > .section-heading:first-child,
.card > .section-heading:first-child {
    margin-top: 0;
}

/* Section heading followed by tabs should have no bottom margin */
.section-heading + .tab-radio {
    margin-bottom: 0;
}

.section-heading:has(+ .tab-radio) {
    margin-bottom: 0;
}

/* Scrollbar styling - shared pattern */
.custom-scrollbar::-webkit-scrollbar {
    width: 8px;
}

.custom-scrollbar::-webkit-scrollbar-track {
    background: transparent;
}

.custom-scrollbar::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

.custom-scrollbar::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Wide scrollbar variant for main content */
.custom-scrollbar-wide::-webkit-scrollbar {
    width: 12px;
}

.custom-scrollbar-wide::-webkit-scrollbar-track {
    background: transparent;
}

.custom-scrollbar-wide::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 6px;
}

.custom-scrollbar-wide::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* ============================================
   INPUT GROUPS (used across all calculators)
   ============================================ */
.input-group {
    margin-bottom: var(--spacing-2xl);
}

label {
    display: block;
    margin-bottom: var(--spacing-md);
    font-weight: 500;
    color: var(--text-secondary);
}

input {
    width: 100%;
    padding: var(--spacing-lg);
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: var(--spacing-xl);
    background-color: var(--input-bg);
    color: var(--text-primary);
    transition: border-color 0.2s, outline 0.2s;
    margin-bottom: var(--spacing-sm);
    outline: 2px solid transparent;
    outline-offset: 0px;
}

input:hover:not(:focus) {
    outline: 2px solid var(--accent-outline);
}

input.error {
    border-color: var(--error-color);
}

input::placeholder {
    color: var(--text-secondary);
    opacity: 0.6;
}

input:focus {
    outline: 2px solid var(--accent-color);
    border-color: var(--accent-color);
}

input.error {
    border-color: var(--error-color);
}

input.error:hover:not(:focus) {
    outline: 2px solid var(--error-outline);
}

input.error:focus {
    outline: 2px solid var(--error-color);
}

select {
    width: 100%;
    padding: var(--spacing-lg) 2.5rem var(--spacing-lg) var(--spacing-lg);
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: var(--spacing-xl);
    background-color: var(--input-bg);
    color: var(--text-primary);
    transition: border-color 0.2s, outline 0.2s;
    margin-bottom: var(--spacing-sm);
    cursor: pointer;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%236B6B6B' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right var(--spacing-lg) center;
    background-size: 12px;
    outline: 2px solid transparent;
    outline-offset: 0px;
}

select:hover:not(:focus) {
    outline: 2px solid var(--accent-outline);
}

select:focus {
    outline: 2px solid var(--accent-color);
    border-color: var(--accent-color);
}

/* WebKit/Blink specific option styling
   Note: Chrome/Safari don't support custom styling of the dropdown menu itself.
   The dropdown appearance is controlled by the OS. Only Firefox supports
   significant option styling. These rules provide basic cross-browser support. */
select option {
    padding: var(--spacing-md) var(--spacing-lg);
    background-color: var(--input-bg);
    color: var(--text-primary);
    font-size: var(--spacing-xl);
}

select option:checked {
    background: var(--accent-color);
    color: white;
    font-weight: 600;
}

select option:disabled {
    color: var(--text-secondary);
    font-weight: 700;
    font-style: italic;
}

/* ============================================
   ERROR MESSAGES
   ============================================ */
.error-message {
    color: var(--error-color);
    font-size: 0.875rem;
    margin-top: 0;
    margin-bottom: var(--spacing-sm);
    display: none;
    min-height: 1.2rem;
}

.error-message.show {
    display: block;
}

button {
    width: 100%;
    padding: 0.875rem;
    background-color: var(--accent-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: var(--spacing-xl);
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.2s;
    margin-top: var(--spacing-md);
}

button:hover {
    opacity: 0.9;
}

.show-more-btn {
    width: auto;
    min-width: 200px;
    margin: var(--spacing-2xl) auto 0 auto;
    display: block;
}

.results {
    display: none;
    padding: var(--spacing-3xl);
}

.results.show {
    display: block;
}

.results.fade-in {
    animation: fadeIn 0.2s ease-in-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.results h3 {
    margin-bottom: var(--spacing-2xl);
    color: var(--text-primary);
    font-size: var(--spacing-2xl);
}

.result-section-heading {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--accent-color);
    margin: var(--spacing-2xl) 0 var(--spacing-lg) 0;
    padding-bottom: var(--spacing-xs);
    border-bottom: 1px solid var(--border-color);
}

.result-section-heading:first-of-type {
    margin-top: 0;
}

.result-group {
    margin-bottom: var(--spacing-2xl);
}

.result-group:last-child {
    margin-bottom: 0;
}

.result-item {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    background-color: var(--bg-primary);
    border-radius: 6px;
    border-left: 4px solid var(--accent-color);
}

.result-description {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
    padding: 0 var(--spacing-xl) 0 var(--spacing-xl);
}

/* Shared label/value patterns for result displays */
.result-label,
.ratio-label {
    font-weight: 500;
    color: var(--text-secondary);
}

.result-value,
.ratio-value {
    color: var(--accent-color);
    font-weight: 700;
}

.result-value {
    font-size: 1.1rem;
}

.formula {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-family: 'SF Mono', 'Monaco', 'Consolas', 'Liberation Mono', 'Courier New', monospace;
    background-color: var(--bg-primary);
    padding: var(--spacing-md) var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    border-radius: 4px;
    border-left: 3px solid var(--border-color);
}

.result-formula {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.5;
    padding: 0 var(--spacing-xl);
    margin-top: 0;
    margin-bottom: var(--spacing-md);
}

.math {
    font-family: 'SF Mono', 'Monaco', 'Consolas', 'Liberation Mono', 'Courier New', monospace;
    font-size: 1em;
}

.about-content {
    padding: var(--spacing-3xl);
    line-height: 1.8;
    max-width: 900px;
}

.about-content p {
    margin-bottom: var(--spacing-xl);
}

a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 600;
    border-bottom: 2px solid transparent;
    transition: border-bottom-color 0.2s ease;
}

.about-content a:hover {
    border-bottom-color: var(--accent-color);
}

.guide-content a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 600;
    border-bottom: 2px solid transparent;
    transition: border-bottom-color 0.2s ease;
}

/* Contact Section */
.contact-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-3xl);
    max-width: 1200px;
}

.contact-form {
    padding: var(--spacing-3xl);
}

.contact-form textarea {
    width: 100%;
    padding: var(--spacing-lg);
    background-color: var(--input-bg);
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 1rem;
    color: var(--text-primary);
    font-family: inherit;
    resize: vertical;
    min-height: 150px;
    transition: border-color 0.2s, outline 0.2s;
    outline: 2px solid transparent;
    outline-offset: 0px;
}

.contact-form textarea:hover:not(:focus) {
    outline: 2px solid var(--accent-outline);
}

.contact-form textarea:focus {
    outline: none;
    border-color: var(--accent-color);
}

.contact-form textarea::placeholder {
    color: var(--text-secondary);
}

.contact-submit {
    width: 100%;
    padding: var(--spacing-xl) var(--spacing-2xl);
    background-color: var(--accent-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease;
    margin-top: var(--spacing-md);
}

.contact-submit:hover {
    background-color: var(--accent-hover);
}

.contact-submit:active {
    transform: scale(0.98);
}

.contact-info {
    padding: var(--spacing-2xl);
    line-height: 1.6;
}

.contact-info h3 {
    margin: 0 0 var(--spacing-md) 0;
    color: var(--accent-color);
}

.contact-info ul {
    margin: 0 0 var(--spacing-lg) 0;
    padding-left: var(--spacing-xl);
}

.contact-info li {
    margin-bottom: var(--spacing-sm);
}

.contact-response-note {
    margin: 0;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.guide-content a:hover {
    border-bottom-color: var(--accent-color);
}

/* Layout styles inherited from shared .calculator-layout rule above */

/* ============================================
   GEAR CALCULATOR LAYOUT
   ============================================ */
.gear-layout {
    display: block;
    max-width: 1200px;
    width: 100%;
}

/* Inputs section contains the three columns */
.gear-layout .inputs-section {
    background-color: transparent;
    padding: 0;
    box-shadow: none;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-3xl);
}

/* Each gear column is a card */
.gear-column {
    background-color: var(--bg-secondary);
    padding: var(--spacing-2xl);
    border-radius: 8px;
    box-shadow: 0 2px 8px var(--overlay-dark-medium);
    transition: box-shadow 0.2s ease;
}

.gear-column.error {
    box-shadow: 0 0 0 2px var(--error-color);
}

.gear-column .error-message {
    margin-top: var(--spacing-xl);
    text-align: center;
}

/* Planetary gear section styling */
.planetary-section {
    grid-column: 1 / -1;
    margin-top: var(--spacing-2xl);
    padding: var(--spacing-2xl);
}

.planetary-toggle {
    margin-bottom: var(--spacing-md);
}

.planetary-note {
    margin-bottom: var(--spacing-xl);
    padding-left: 0;
}

.planetary-inputs {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height 0.3s ease, opacity 0.3s ease, margin-top 0.3s ease;
}

.planetary-section:has(#include-planetary:checked) .planetary-inputs {
    max-height: 200px;
    opacity: 1;
    margin-top: var(--spacing-xl);
}

.planetary-section:has(#include-planetary:not(:checked)) .planetary-inputs input {
    pointer-events: none;
}

/* Planetary inputs in ratio calculator differential sections */
.ratio-section .planetary-inputs {
    grid-template-columns: 1fr 1fr 1fr;
    margin-top: 0;
}

.ratio-section:has(#center-planetary:checked) #center-planetary-inputs {
    max-height: 200px;
    opacity: 1;
    margin-top: var(--spacing-xl);
}

.ratio-section:has(#rear-planetary:checked) #rear-planetary-inputs {
    max-height: 200px;
    opacity: 1;
    margin-top: var(--spacing-xl);
}

.ratio-section:has(#front-planetary:checked) #front-planetary-inputs {
    max-height: 200px;
    opacity: 1;
    margin-top: var(--spacing-xl);
}

/* Section headers within each column */
.input-section-header {
    font-weight: 600;
    color: var(--accent-color);
    margin-top: 0;
    margin-bottom: var(--spacing-xl);
    font-size: 1.1rem;
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Lock control container */
.lock-control {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

/* Lock label */
.lock-label {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    min-width: 80px;
    text-align: right;
}

/* ============================================
   SHARED TOGGLE/SLIDER STYLES
   ============================================ */
/* Base slider appearance (shared by all toggle types) */
.toggle-slider,
.checkbox-slider {
    position: relative;
    width: 50px;
    height: 26px;
    background-color: var(--border-color);
    border-radius: 26px;
    transition: 0.3s;
    flex-shrink: 0;
}

.toggle-slider:before,
.checkbox-slider:before {
    content: "";
    position: absolute;
    height: 20px;
    width: 20px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    border-radius: 50%;
    transition: 0.3s;
}

/* Checked state (shared) */
input:checked + .toggle-slider,
input:checked + .checkbox-slider,
input[type="checkbox"]:checked + .checkbox-slider {
    background-color: var(--accent-color);
}

input:checked + .toggle-slider:before,
input:checked + .checkbox-slider:before,
input[type="checkbox"]:checked + .checkbox-slider:before {
    transform: translateX(24px);
}

/* Toggle Switch Container */
.toggle-switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 26px;
    margin: 0;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
    margin: 0;
    padding: 0;
}

.toggle-switch .toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
}

input:focus + .toggle-slider {
    box-shadow: 0 0 1px var(--accent-color);
}

/* Gear calculator specific field styling */
.calculated-field {
    font-style: normal;
}

.calculated-field::placeholder {
    font-style: italic;
    opacity: 0.5;
}

/* Button wrapper - center relative to pitch column on desktop */
.gear-button-wrapper {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-3xl);
    margin-top: var(--spacing-xl);
}

.gear-calculate-button {
    grid-column: 2;
    max-width: 100%;
}

/* Stack columns on mobile */
@media (max-width: 900px) {
    .gear-layout .inputs-section {
        grid-template-columns: 1fr;  /* Single column on mobile */
    }

    .gear-button-wrapper {
        grid-template-columns: 1fr;
    }

    .gear-calculate-button {
        grid-column: 1;
        max-width: 400px;
        margin: 0 auto;
    }
}

/* ============================================
   GEAR RATIO CALCULATOR LAYOUT
   ============================================ */
.gear-ratio-layout {
    max-width: 1200px;
    width: 100%;
}

.vehicle-presets {
    padding: var(--spacing-2xl);
    margin-bottom: var(--spacing-3xl);
}

.vehicle-presets h3 {
    margin-bottom: var(--spacing-xl);
    font-size: 1.2rem;
    padding-bottom: var(--spacing-md);
}

.preset-inputs {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
}

.gear-ratio-grid {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-3xl);
    margin-bottom: var(--spacing-3xl);
}

.ratio-section {
    padding: var(--spacing-2xl);
    transition: opacity 0.3s ease;
    position: relative;
}

.ratio-section:not(:first-child)::before {
    content: '↓';
    position: absolute;
    top: calc(var(--spacing-3xl) / -2);
    left: 50%;
    transform: translate(-50%, -60%);
    font-size: var(--spacing-2xl);
    line-height: 1;
    color: var(--accent-color);
    opacity: 0.5;
}

.ratio-section.disabled {
    opacity: 0.5;
}

.ratio-section.disabled .ratio-inputs,
.ratio-section.disabled .ratio-result,
.ratio-section.disabled .checkbox-option,
.ratio-section.disabled .radio-group {
    display: none;
}

.ratio-section.disabled .section-header-with-toggle {
    margin-bottom: 0;
    padding-bottom: 0;
}

.ratio-section.disabled h3 {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

/* CSS-only toggle for hiding sections when checkbox is not checked */
/* Consolidated pattern for all diff sections including transmission */
.ratio-section:has(#include-transmission:not(:checked)) .ratio-inputs,
.ratio-section:has(#include-transmission:not(:checked)) .ratio-result,
.ratio-section:has(#include-center-diff:not(:checked)) .ratio-inputs,
.ratio-section:has(#include-center-diff:not(:checked)) .ratio-result,
.ratio-section:has(#include-center-diff:not(:checked)) .checkbox-option,
.ratio-section:has(#include-center-diff:not(:checked)) .radio-group,
.ratio-section:has(#include-rear-diff:not(:checked)) .ratio-inputs,
.ratio-section:has(#include-rear-diff:not(:checked)) .ratio-result,
.ratio-section:has(#include-rear-diff:not(:checked)) .checkbox-option,
.ratio-section:has(#include-rear-diff:not(:checked)) .radio-group,
.ratio-section:has(#include-front-diff:not(:checked)) .ratio-inputs,
.ratio-section:has(#include-front-diff:not(:checked)) .ratio-result,
.ratio-section:has(#include-front-diff:not(:checked)) .checkbox-option,
.ratio-section:has(#include-front-diff:not(:checked)) .radio-group {
    display: none;
}

.ratio-section:has(#include-transmission:not(:checked)),
.ratio-section:has(#include-center-diff:not(:checked)),
.ratio-section:has(#include-rear-diff:not(:checked)),
.ratio-section:has(#include-front-diff:not(:checked)) {
    opacity: 0.5;
}

.ratio-section:has(#include-transmission:not(:checked)) .section-header-with-toggle,
.ratio-section:has(#include-center-diff:not(:checked)) .section-header-with-toggle,
.ratio-section:has(#include-rear-diff:not(:checked)) .section-header-with-toggle,
.ratio-section:has(#include-front-diff:not(:checked)) .section-header-with-toggle {
    margin-bottom: 0;
    padding-bottom: 0;
}

.ratio-section:has(#include-transmission:not(:checked)) h3,
.ratio-section:has(#include-center-diff:not(:checked)) h3,
.ratio-section:has(#include-rear-diff:not(:checked)) h3,
.ratio-section:has(#include-front-diff:not(:checked)) h3 {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.ratio-section .checkbox-option {
    margin-top: var(--spacing-xl);
}

.ratio-section h3 {
    margin-bottom: var(--spacing-xl);
    font-size: 1.2rem;
    padding-bottom: var(--spacing-md);
}

.section-header-with-toggle {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
}

.section-header-with-toggle h3 {
    margin: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.toggle-section {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    cursor: pointer;
}

.toggle-section input[type="checkbox"] {
    display: none;
}

/* Slider styles inherited from shared section above */

.toggle-section::after {
    content: 'Off';
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
    min-width: 2rem;
}

.toggle-section:has(input[type="checkbox"]:checked)::after {
    content: 'On';
    color: var(--accent-color);
}

.ratio-inputs {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    margin-bottom: 0;
}

.ratio-result {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-xl);
    background-color: var(--bg-primary);
    border-radius: 6px;
    border-left: 4px solid var(--accent-color);
}

/* Additional specific styling for ratio displays */
.ratio-label {
    font-weight: 600;
}

.ratio-value {
    font-size: 1.3rem;
    font-family: 'Courier New', monospace;
}

.overall-ratios {
    padding: var(--spacing-2xl);
    grid-column: 1 / -1;
}

.overall-ratios h3 {
    margin-bottom: var(--spacing-2xl);
    font-size: 1.3rem;
}

.gear-ratio-calculate-button {
    margin-top: var(--spacing-md);
    max-width: 400px;
    margin-left: auto;
    margin-right: auto;
    display: block;
}

/* Checkbox Option Styling (matches toggle switches) */
.checkbox-options {
    margin-bottom: var(--spacing-2xl);
}

.checkbox-option {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    padding: var(--spacing-lg);
    border-radius: 6px;
    margin-bottom: var(--spacing-md);
    cursor: pointer;
    transition: background-color 0.2s;
}

.checkbox-option:hover {
    background-color: var(--bg-primary);
}

.checkbox-option input[type="checkbox"] {
    display: none;
}

/* Slider styles inherited from shared section above */

.checkbox-label {
    font-size: 0.95rem;
    color: var(--text-primary);
    font-weight: 500;
}

/* Radio group styles */
.radio-group {
    display: flex;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
    margin-bottom: 0;
}

.radio-option {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.radio-option:hover {
    background-color: var(--bg-primary);
}

.radio-option input[type="radio"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--accent-color);
}

.radio-label {
    font-size: 0.95rem;
    color: var(--text-primary);
    font-weight: 500;
    cursor: pointer;
}

.calculator-layout .inputs-section {
    min-height: 0;
}

.load-bank-layout .results.show,
#gear-results.show {
    min-height: 400px;
}

.voltage-tables {
    visibility: hidden;
    opacity: 0;
    height: 0;
    overflow: hidden;
    margin-top: 0;
    transition: opacity 0.2s ease-in-out;
}

.voltage-tables.show {
    visibility: visible;
    opacity: 1;
    height: auto;
    margin-top: var(--spacing-3xl);
}

.voltage-table-container {
    margin-bottom: var(--spacing-4xl);
}

.voltage-table-container h3 {
    margin-bottom: var(--spacing-xl);
    color: var(--text-primary);
    font-size: 1.3rem;
}

.table-wrapper {
    overflow-x: auto;
    padding: var(--spacing-xl);
}

.voltage-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    font-size: 0.9rem;
    border: 3px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
}

.voltage-table th {
    background-color: #4A5F7A;
    color: white;
    font-weight: 600;
    padding: var(--spacing-lg) var(--spacing-md);
    text-align: center;
    border: 1px solid var(--border-color);
}

.voltage-table thead tr:first-child th {
    border-bottom: 3px solid var(--header-border);
    font-weight: 700;
    font-size: 1em;
}

.voltage-table thead tr:last-child th {
    background-color: #6B7F99;
    color: white;
    border-bottom: 3px solid var(--border-color);
    font-weight: 700;
    font-size: 0.95em;
}

/* Thicker borders between sections */
.voltage-table thead tr:first-child th:nth-child(1) {
    border-right: 4px solid var(--border-color);
}

.voltage-table thead tr:first-child th:nth-child(2) {
    border-right: 4px solid var(--border-color);
}

.voltage-table thead tr:last-child th:nth-child(2),
.voltage-table tbody td:nth-child(2) {
    border-right: 4px solid var(--border-color);
}

.voltage-table thead tr:last-child th:nth-child(5),
.voltage-table tbody td:nth-child(5) {
    border-right: 4px solid var(--border-color);
}

/* Regular borders for other columns */
.voltage-table thead tr:last-child th:not(:nth-child(2)):not(:nth-child(5)),
.voltage-table tbody td:not(:nth-child(2)):not(:nth-child(5)) {
    border-right: 1px solid var(--border-color);
}

.voltage-table td {
    padding: var(--spacing-lg) var(--spacing-md);
    text-align: center;
    border: 1px solid var(--border-color);
}

.voltage-table tbody tr:nth-child(even) {
    background-color: var(--bg-primary);
}

.voltage-table tbody tr:nth-child(odd) {
    background-color: var(--bg-secondary);
}

.watt-safe {
    color: var(--success-color);
    font-weight: 600;
    background-color: var(--success-bg);
}

.watt-danger {
    color: var(--error-color);
    font-weight: 600;
    background-color: var(--error-bg);
}

/* Tooltip for table headers - uses JS-positioned tooltip element */
.tooltip-header {
    position: relative;
    cursor: help;
    text-decoration: underline dotted;
    text-underline-offset: 2px;
}

/* Global tooltip element positioned via JavaScript */
.tooltip-popup {
    position: fixed;
    background-color: var(--text-primary);
    color: var(--bg-primary);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: normal;
    white-space: normal;
    max-width: 250px;
    text-align: left;
    z-index: 10000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.2s, visibility 0.2s;
    pointer-events: none;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    line-height: 1.4;
}

.tooltip-popup.visible {
    opacity: 1;
    visibility: visible;
}

/* Arrow for tooltip popup */
.tooltip-popup::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 6px solid transparent;
    border-top-color: var(--text-primary);
}

/* Mobile tooltip adjustments */
@media (max-width: 768px) {
    .tooltip-popup {
        position: fixed !important;
        max-width: calc(100vw - 20px);
        left: 10px !important;
        right: 10px !important;
        width: auto !important;
    }

    .tooltip-popup::after {
        display: none;
    }
}

.note-text {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: var(--spacing-sm);
    font-style: italic;
}

.config-section {
    margin-bottom: var(--spacing-2xl);
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
}

.config-section h4 {
    color: var(--accent-color);
    margin-bottom: var(--spacing-lg);
    font-size: 1.1rem;
    grid-column: 1 / -1;
}

/* Tablet - stack when word wrapping starts to occur */
@media (max-width: 1100px) {
    .calculator-layout {
        grid-template-columns: 1fr;
        gap: var(--spacing-2xl);
    }

    .results {
        position: static;
    }

    .load-bank-layout {
        grid-template-columns: 1fr;
    }

    .config-section {
        grid-template-columns: 1fr;
    }

    .contact-layout {
        grid-template-columns: 1fr;
    }
}

/* Split tables at larger breakpoint for better readability */
@media (max-width: 900px) {
    .voltage-table-container {
        margin-bottom: var(--spacing-3xl);
    }

    .mobile-table-split {
        margin-bottom: var(--spacing-3xl);
    }

    .mobile-table-split h4 {
        background-color: #4A5F7A;
        color: white;
        padding: var(--spacing-lg);
        margin: 0 0 var(--spacing-md) 0;
        border-radius: 6px 6px 0 0;
        font-size: var(--spacing-xl);
    }

    .mobile-table-split .table-wrapper {
        display: block !important;
        background-color: var(--bg-secondary);
    }

    .mobile-table-split table {
        width: 100%;
        display: table !important;
        font-size: 0.9rem;
    }

    .mobile-table-split .voltage-table th,
    .mobile-table-split .voltage-table td {
        padding: var(--spacing-lg) var(--spacing-md);
        font-size: 0.85rem;
    }

    /* Hide full table on mobile, show split version */
    .voltage-table-container > .table-wrapper:first-of-type {
        display: none !important;
    }

    .mobile-split-tables {
        display: block !important;
    }
}

/* Mobile Layout */
@media (max-width: 768px) {
    html, body {
        margin: 0 !important;
        padding: 0 !important;
        overflow-x: hidden;
    }

    body {
        flex-direction: column;
        padding-top: 4rem !important;
    }

    .sidebar {
        position: fixed;
        left: -100%;
        top: 4rem;
        height: calc(100dvh - 4rem);
        width: var(--sidebar-width);
        transition: left 0.3s ease;
        box-shadow: 2px 0 10px rgba(0, 0, 0, 0.1);
    }

    .hamburger:has(#menu-toggle:checked) ~ .sidebar {
        left: 0;
    }

    .hamburger {
        cursor: default;
        display: flex;
        flex-direction: row;
        align-items: center;
        justify-content: flex-start;
        position: fixed;
        top: 0 !important;
        left: 0 !important;
        right: 0;
        width: 100%;
        height: 4rem;
        background-color: var(--bg-secondary);
        border: none;
        border-bottom: 2px solid var(--border-color);
        border-radius: 0;
        padding: 0 0.5rem;
        margin: 0 !important;
        z-index: 101;
        transition: all 0.3s ease;
        pointer-events: auto;
    }

    .nav-header {
        display: none;
    }

    .hamburger .mobile-title {
        display: flex;
        align-items: baseline;
        font-size: 1.4rem;
        font-weight: 700;
        text-align: center;
        flex: 1;
        order: 2;
        justify-content: center;
    }

    .hamburger .mobile-title .logo-calc {
        color: var(--text-primary);
    }

    .hamburger .mobile-title .logo-labs {
        color: var(--accent-color);
    }

    .hamburger .mobile-title .mobile-subtitle {
        color: var(--text-secondary);
        font-weight: 600;
        font-size: 1.1rem;
        margin-left: 0.5rem;
        text-transform: uppercase;
        letter-spacing: 0.1em;
    }

    .hamburger::after {
        content: '';
        width: 2.5rem;
        flex-shrink: 0;
        order: 3;
    }

    .hamburger-icon {
        width: 2.5rem;
        height: 2.5rem;
        display: flex;
        flex-direction: column;
        justify-content: space-around;
        padding: 0.5rem;
        flex-shrink: 0;
        z-index: 1;
        pointer-events: auto;
        order: 1;
        cursor: pointer;
    }

    .hamburger:hover {
        background-color: var(--bg-secondary);
    }

    .hamburger-icon span {
        width: 100%;
        height: 3px;
        background-color: var(--text-primary);
        border-radius: 2px;
        transition: all 0.3s ease;
    }

    .hamburger #menu-toggle:checked ~ .hamburger-icon span:nth-child(1) {
        transform: rotate(45deg) translate(0.35rem, 0.35rem);
    }

    .hamburger #menu-toggle:checked ~ .hamburger-icon span:nth-child(2) {
        opacity: 0;
    }

    .hamburger #menu-toggle:checked ~ .hamburger-icon span:nth-child(3) {
        transform: rotate(-45deg) translate(0.35rem, -0.35rem);
    }

    /* Close menu when clicking on navigation links */
    .sidebar a {
        position: relative;
    }

    main {
        margin-left: 0;
        width: 100%;
        padding: var(--spacing-xl);
    }

    .calculator h2 {
        font-size: var(--spacing-2xl);
        margin-bottom: var(--spacing-md);
    }

    .calculator-description {
        font-size: 0.9rem;
        margin-bottom: var(--spacing-2xl);
    }

    .inputs-section,
    .results {
        padding: var(--spacing-2xl);
    }

    .ratio-inputs {
        grid-template-columns: 1fr;
    }

    .gear-ratio-grid {
        grid-template-columns: 1fr;
    }

    .contact-form,
    .contact-info {
        padding: var(--spacing-xl);
        width: 100%;
        max-width: 100%;
        box-sizing: border-box;
    }

    .contact-form .input-group {
        overflow: hidden;
    }

    .contact-form .cf-turnstile,
    .contact-form .cf-turnstile iframe {
        max-width: 100% !important;
        width: 100% !important;
    }
}

.mobile-split-tables {
    display: none;
}

/* Small Tablet Layout */
@media (min-width: 769px) and (max-width: 1024px) {
    :root {
        --sidebar-width: 200px;
    }

    .nav-header h1 {
        font-size: 2rem;
    }

    .sidebar a {
        padding: var(--spacing-lg) var(--spacing-xl);
        font-size: 0.9rem;
    }
}

/* =========================================
   TAB COMPONENTS (CSS-only with :checked)
   ========================================= */
.tab-container {
    margin-bottom: 0;
}

/* Section heading that precedes tabs should have minimal bottom margin */
.section-heading-with-tabs {
    margin-bottom: 0 !important;
}

/* Tab container that follows a heading should have minimal top margin */
.tab-container-after-heading {
    margin-top: var(--spacing-sm) !important;
}

/* Hide radio inputs */
.tab-radio {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.tab-buttons {
    display: flex;
    gap: 0;
    border: 1px solid var(--border-color);
    border-bottom: none;
    background-color: var(--bg-secondary);
    border-radius: 6px 6px 0 0;
}

.tab-button {
    flex: 1;
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-secondary);
    border: none;
    border-right: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    border-radius: 0;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    text-align: center;
    transition: background 0.15s ease, color 0.15s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.tab-button:first-child {
    border-radius: 6px 0 0 0;
}

.tab-button:last-child {
    border-right: none;
    border-radius: 0 6px 0 0;
}

.tab-button:hover {
    background: var(--card-bg);
    color: var(--text-primary);
}

/* Active tab styling via :checked - target by ID */
#speed-gear-tab-simple:checked ~ .tab-container .tab-button:first-child,
#speed-area-tab-dimensions:checked ~ .tab-container .tab-button:first-child {
    color: var(--accent-color);
    font-weight: 700;
    background: var(--card-bg);
    border-bottom: none;
}

#speed-gear-tab-advanced:checked ~ .tab-container .tab-button:last-child,
#speed-area-tab-direct:checked ~ .tab-container .tab-button:last-child {
    color: var(--accent-color);
    font-weight: 700;
    background: var(--card-bg);
    border-bottom: none;
}

/* Show/hide tab content based on :checked - using general sibling combinator */
.tab-content {
    display: none;
}

/* Show first tab content when first radio is checked */
#speed-gear-tab-simple:checked ~ #speed-gear-simple-inputs,
#speed-area-tab-dimensions:checked ~ #speed-area-dimensions-inputs {
    display: block;
}

/* Show second tab content when second radio is checked */
#speed-gear-tab-advanced:checked ~ #speed-gear-advanced-inputs,
#speed-area-tab-direct:checked ~ #speed-area-direct-inputs {
    display: block;
}

.tab-section-label {
    display: block;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    margin-top: 0;
}

/* When section-heading comes before tabs, remove its bottom margin */
.section-heading + .tab-section-label {
    margin-top: var(--spacing-sm);
}

/* =========================================
   SUBSECTION HEADINGS
   ========================================= */
.subsection-heading {
    font-size: 1rem;
    font-weight: 600;
    color: var(--accent-color);
    margin: var(--spacing-xl) 0 var(--spacing-md) 0;
    padding-bottom: var(--spacing-xs);
    border-bottom: 1px solid var(--border-color);
}

/* First subsection shouldn't have top margin */
.section-heading + .subsection-heading,
h3 + .subsection-heading {
    margin-top: var(--spacing-md);
}

/* Guide section headings (H3 within usage guides) */
.guide-section-heading {
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--accent-color);
    margin: var(--spacing-xl) 0 var(--spacing-md) 0;
    padding-bottom: 0;
    border-bottom: none;
}

.guide-content .guide-section-heading:first-child {
    margin-top: 0;
}

/* Input + select pattern (unit dropdown after input) */
.input-with-unit {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.input-with-unit input {
    flex: 1;
    margin-bottom: 0;
}

.input-with-unit select {
    width: 108px;
    flex-shrink: 0;
    margin-bottom: 0;
    padding: var(--spacing-lg);
}

/* Tab content boxes */
.tab-content {
    border: 1px solid var(--border-color);
    border-top: none;
    border-radius: 0 0 6px 6px;
    padding: var(--spacing-xl);
    margin-top: 0;
    margin-bottom: var(--spacing-xl);
    background-color: var(--card-bg);
}

/* Wrapper for inputs inside tab-content - removes bottom margin from last input */
.tab-inputs {
    margin-bottom: 0;
}

.tab-inputs .input-group:last-child {
    margin-bottom: 0;
}

/* When result shown, add margin to tab-inputs wrapper */
.tab-content.has-result .tab-inputs {
    margin-bottom: var(--spacing-2xl);
}

/* Hide calculated results by default */
#speed-calculated-ratio-display,
#speed-calculated-area-display {
    display: none;
}

/* Result groups have no margin - spacing comes from tab-inputs wrapper */
.tab-content .result-group {
    margin: 0;
}

/* Advanced Options - override padding from guide-content to match inputs-section */
#speed-advanced-options .guide-content {
    padding: 0 var(--spacing-3xl) 0 var(--spacing-3xl);
}