/* =====================================================
   Material Design 3 (Android 16) Theme - EveryCalc
   ===================================================== */

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* M3 Design Tokens - Light Theme */
:root {
    /* Primary */
    --md-primary: #6750A4;
    --md-on-primary: #FFFFFF;
    --md-primary-container: #EADDFF;
    --md-on-primary-container: #21005D;
    --md-primary-rgb: 103, 80, 164;

    /* Secondary */
    --md-secondary: #625B71;
    --md-on-secondary: #FFFFFF;
    --md-secondary-container: #E8DEF8;
    --md-on-secondary-container: #1D192B;

    /* Tertiary */
    --md-tertiary: #7D5260;
    --md-on-tertiary: #FFFFFF;
    --md-tertiary-container: #FFD8E4;
    --md-on-tertiary-container: #31111D;

    /* Error */
    --md-error: #B3261E;
    --md-on-error: #FFFFFF;
    --md-error-container: #F9DEDC;

    /* Surface & Background */
    --md-surface: #FEF7FF;
    --md-surface-dim: #DED8E1;
    --md-surface-bright: #FEF7FF;
    --md-surface-container-lowest: #FFFFFF;
    --md-surface-container-low: #F7F2FA;
    --md-surface-container: #F3EDF7;
    --md-surface-container-high: #ECE6F0;
    --md-surface-container-highest: #E6E0E9;
    --md-on-surface: #1D1B20;
    --md-on-surface-variant: #49454F;
    --md-on-surface-rgb: 29, 27, 32;

    /* Outline */
    --md-outline: #79747E;
    --md-outline-variant: #CAC4D0;

    /* Inverse */
    --md-inverse-surface: #322F35;
    --md-inverse-on-surface: #F5EFF7;
    --md-inverse-primary: #D0BCFF;

    /* Elevation & Shadows (M3 tonal elevation) */
    --md-elevation-1: 0px 1px 3px 1px rgba(0, 0, 0, 0.15), 0px 1px 2px 0px rgba(0, 0, 0, 0.3);
    --md-elevation-2: 0px 2px 6px 2px rgba(0, 0, 0, 0.15), 0px 1px 2px 0px rgba(0, 0, 0, 0.3);
    --md-elevation-3: 0px 4px 8px 3px rgba(0, 0, 0, 0.15), 0px 1px 3px 0px rgba(0, 0, 0, 0.3);
    --md-elevation-4: 0px 6px 10px 4px rgba(0, 0, 0, 0.15), 0px 2px 3px 0px rgba(0, 0, 0, 0.3);

    /* Shape (M3 Shape Scale) */
    --md-shape-none: 0px;
    --md-shape-xs: 4px;
    --md-shape-sm: 8px;
    --md-shape-md: 12px;
    --md-shape-lg: 16px;
    --md-shape-xl: 28px;
    --md-shape-full: 9999px;

    /* Motion */
    --md-motion-easing-standard: cubic-bezier(0.2, 0, 0, 1);
    --md-motion-easing-emphasized: cubic-bezier(0.2, 0, 0, 1);
    --md-motion-easing-decelerate: cubic-bezier(0, 0, 0, 1);
    --md-motion-easing-accelerate: cubic-bezier(0.3, 0, 1, 1);
    --md-motion-duration-short: 200ms;
    --md-motion-duration-medium: 300ms;
    --md-motion-duration-long: 500ms;

    /* State layers */
    --md-state-hover-opacity: 0.08;
    --md-state-focus-opacity: 0.12;
    --md-state-pressed-opacity: 0.12;

    /* Legacy aliases for backwards compat with calc pages */
    --primary-color: var(--md-primary);
    --primary-color-rgb: var(--md-primary-rgb);
    --primary-hover: #7F67BE;
    --secondary-color: var(--md-secondary);
    --success-color: #4CAF50;
    --warning-color: #FFC107;
    --danger-color: #F44336;
    --background-color: var(--md-surface);
    --card-background: var(--md-surface-container);
    --input-background: var(--md-surface-container-highest);
    --text-primary: var(--md-on-surface);
    --text-primary-rgb: var(--md-on-surface-rgb);
    --text-secondary: var(--md-on-surface-variant);
    --border-color: var(--md-outline-variant);
    --shadow-sm: var(--md-elevation-1);
    --shadow-md: var(--md-elevation-2);
    --shadow-lg: var(--md-elevation-3);
    --radius-sm: var(--md-shape-sm);
    --radius-md: var(--md-shape-md);
    --radius-lg: var(--md-shape-lg);
    --modal-backdrop: rgba(0, 0, 0, 0.4);
    --highlight-color: rgba(103, 80, 164, 0.2);
}

/* M3 Dark Theme */
[data-theme="dark"] {
    --md-primary: #D0BCFF;
    --md-on-primary: #381E72;
    --md-primary-container: #4F378B;
    --md-on-primary-container: #EADDFF;
    --md-primary-rgb: 208, 188, 255;

    --md-secondary: #CCC2DC;
    --md-on-secondary: #332D41;
    --md-secondary-container: #4A4458;
    --md-on-secondary-container: #E8DEF8;

    --md-tertiary: #EFB8C8;
    --md-on-tertiary: #492532;
    --md-tertiary-container: #633B48;
    --md-on-tertiary-container: #FFD8E4;

    --md-error: #F2B8B5;
    --md-on-error: #601410;
    --md-error-container: #8C1D18;

    --md-surface: #141218;
    --md-surface-dim: #141218;
    --md-surface-bright: #3B383E;
    --md-surface-container-lowest: #0F0D13;
    --md-surface-container-low: #1D1B20;
    --md-surface-container: #211F26;
    --md-surface-container-high: #2B2930;
    --md-surface-container-highest: #36343B;
    --md-on-surface: #E6E0E9;
    --md-on-surface-variant: #CAC4D0;
    --md-on-surface-rgb: 230, 224, 233;

    --md-outline: #938F99;
    --md-outline-variant: #49454F;

    --md-inverse-surface: #E6E0E9;
    --md-inverse-on-surface: #322F35;
    --md-inverse-primary: #6750A4;

    --md-elevation-1: 0px 1px 3px 1px rgba(0, 0, 0, 0.3), 0px 1px 2px 0px rgba(0, 0, 0, 0.45);
    --md-elevation-2: 0px 2px 6px 2px rgba(0, 0, 0, 0.3), 0px 1px 2px 0px rgba(0, 0, 0, 0.45);
    --md-elevation-3: 0px 4px 8px 3px rgba(0, 0, 0, 0.3), 0px 1px 3px 0px rgba(0, 0, 0, 0.45);
    --md-elevation-4: 0px 6px 10px 4px rgba(0, 0, 0, 0.3), 0px 2px 3px 0px rgba(0, 0, 0, 0.45);

    /* Legacy dark aliases */
    --primary-color: var(--md-primary);
    --primary-color-rgb: var(--md-primary-rgb);
    --primary-hover: #E8DEF8;
    --secondary-color: var(--md-secondary);
    --success-color: #66BB6A;
    --warning-color: #FFD54F;
    --danger-color: #EF5350;
    --background-color: var(--md-surface);
    --card-background: var(--md-surface-container);
    --input-background: var(--md-surface-container-highest);
    --text-primary: var(--md-on-surface);
    --text-primary-rgb: var(--md-on-surface-rgb);
    --text-secondary: var(--md-on-surface-variant);
    --border-color: var(--md-outline-variant);
    --modal-backdrop: rgba(0, 0, 0, 0.6);
    --highlight-color: rgba(208, 188, 255, 0.2);
}

[data-theme="dark"] .input-group input,
[data-theme="dark"] .input-group select {
    background: var(--md-surface-container-high);
    color: var(--md-on-surface);
}

[data-theme="dark"] .gpa-course-row input,
[data-theme="dark"] .gpa-course-row select {
    background: var(--md-surface-container-high);
    color: var(--md-on-surface);
}

/* ==================== BASE STYLES ==================== */

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--md-surface);
    color: var(--md-on-surface);
    line-height: 1.5;
    font-size: 1rem;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ==================== HEADER (Index page only) ==================== */

header:not([class]) {
    background: var(--md-surface-container);
    padding: 32px 0 16px;
    text-align: center;
    border-bottom: none;
    position: sticky;
    top: 0;
    z-index: 100;
    transition: box-shadow var(--md-motion-duration-medium) var(--md-motion-easing-standard);
}

header:not([class]).scrolled {
    box-shadow: var(--md-elevation-2);
}

header:not([class]) h1 {
    font-size: 2rem;
    font-weight: 600;
    color: var(--md-primary);
    margin-bottom: 0;
    letter-spacing: -0.02em;
}

.tagline {
    font-size: 0.95rem;
    color: var(--md-on-surface-variant);
    margin-bottom: 20px;
    margin-top: 4px;
}

.header-top {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 12px;
    margin-bottom: 4px;
    position: relative;
    padding: 0 20px;
}

.header-controls {
    display: flex;
    gap: 8px;
    align-items: center;
    position: static;
    width: auto;
    margin-left: 12px;
}

/* M3 Search Bar */
.search-bar-wrapper {
    position: relative;
    flex-grow: 1;
    max-width: 480px;
    display: flex;
    align-items: center;
}

.search-bar-wrapper .search-icon {
    position: absolute;
    left: 16px;
    color: var(--md-on-surface-variant);
    font-size: 20px;
    pointer-events: none;
}

#header-search-input {
    width: 100%;
    padding: 12px 16px 12px 48px;
    border: none;
    border-radius: var(--md-shape-full);
    font-size: 0.95rem;
    font-family: inherit;
    background: var(--md-surface-container-highest);
    color: var(--md-on-surface);
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
    box-shadow: none;
    outline: none;
}

#header-search-input::placeholder {
    color: var(--md-on-surface-variant);
}

#header-search-input:focus {
    background: var(--md-surface-container-lowest);
    box-shadow: var(--md-elevation-2);
    outline: 2px solid var(--md-primary);
    outline-offset: 0;
}

/* M3 Icon Buttons */
.icon-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: none;
    border-radius: var(--md-shape-full);
    background: transparent;
    color: var(--md-on-surface-variant);
    cursor: pointer;
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
    position: relative;
    overflow: hidden;
}

.icon-btn::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: inherit;
    background: currentColor;
    opacity: 0;
    transition: opacity var(--md-motion-duration-short) var(--md-motion-easing-standard);
}

.icon-btn:hover::before {
    opacity: var(--md-state-hover-opacity);
}

.icon-btn:active::before {
    opacity: var(--md-state-pressed-opacity);
}

.icon-btn:hover {
    color: var(--md-on-surface);
}

[data-theme="dark"] .icon-btn {
    background: transparent;
    box-shadow: none;
}

.sun-icon, .moon-icon {
    display: block;
    position: relative;
    z-index: 1;
}

.icon-btn .moon-icon {
    display: none;
}

.icon-btn[data-theme="dark"] .sun-icon {
    display: none;
}

.icon-btn[data-theme="dark"] .moon-icon {
    display: block;
}

/* ==================== NAVIGATION (M3 Chips) ==================== */

nav {
    display: flex;
    justify-content: center;
    margin-top: 12px;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: center;
    padding: 0 16px;
}

.nav-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    background: var(--md-surface-container-low);
    color: var(--md-on-surface-variant);
    text-decoration: none;
    border-radius: var(--md-shape-sm);
    font-weight: 500;
    font-size: 0.85rem;
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
    border: 1px solid var(--md-outline-variant);
    position: relative;
    overflow: hidden;
}

.nav-link .material-symbols-outlined {
    font-size: 18px;
}

.nav-link::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: inherit;
    background: var(--md-primary);
    opacity: 0;
    transition: opacity var(--md-motion-duration-short) var(--md-motion-easing-standard);
}

.nav-link:hover::before {
    opacity: var(--md-state-hover-opacity);
}

.nav-link:hover {
    color: var(--md-on-surface);
    border-color: var(--md-outline);
}

.nav-link:active {
    transform: scale(0.97);
}

[data-theme="dark"] .nav-link {
    background: var(--md-surface-container-high);
    border-color: var(--md-outline-variant);
}

/* ==================== CONTAINER ==================== */

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ==================== FEATURED SECTION ==================== */

.featured-section {
    padding: 48px 0;
    background: var(--md-primary-container);
    color: var(--md-on-primary-container);
    text-align: center;
    margin-bottom: 0;
}

.featured-section h2 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 28px;
    color: var(--md-on-primary-container);
    letter-spacing: -0.01em;
}

.featured-grid {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    justify-content: center;
    max-width: 960px;
    margin: 0 auto;
}

.featured-section .calculator-card-link {
    background: var(--md-surface-container-lowest);
    color: var(--md-on-surface);
    box-shadow: var(--md-elevation-1);
    border: none;
}

.featured-section .calculator-card-link:hover {
    background: var(--md-surface-container-lowest);
    transform: translateY(-4px);
    box-shadow: var(--md-elevation-3);
}

.featured-section .calculator-card-link h3,
.featured-section .calculator-card-link p {
    color: var(--md-on-surface);
}

.featured-section .calculator-card-link::after {
    color: var(--md-primary);
}

[data-theme="dark"] .featured-section {
    background: var(--md-primary-container);
    color: var(--md-on-primary-container);
}

[data-theme="dark"] .featured-section h2 {
    color: var(--md-on-primary-container);
}

[data-theme="dark"] .featured-section .calculator-card-link {
    background: var(--md-surface-container-high);
}

[data-theme="dark"] .featured-section .calculator-card-link:hover {
    background: var(--md-surface-container-highest);
}

/* ==================== MAIN CONTENT ==================== */

main {
    padding: 32px 0 48px;
}

/* ==================== CALCULATOR SECTIONS ==================== */

.calculator-section {
    margin-bottom: 32px;
    padding: 28px;
    background: var(--md-surface-container-low);
    border-radius: var(--md-shape-xl);
    border: none;
}

.calculator-section h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--md-on-surface);
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: none;
    display: flex;
    align-items: center;
    gap: 10px;
}

.section-icon {
    font-size: 28px;
    color: var(--md-primary);
}

[data-theme="dark"] .calculator-section {
    background: var(--md-surface-container-low);
}

/* ==================== CALCULATOR GRID ==================== */

.calculator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 16px;
}

/* ==================== CALCULATOR CARDS (M3 Filled Card) ==================== */

.calculator-card {
    background: var(--md-surface-container-highest);
    border-radius: var(--md-shape-md);
    padding: 20px;
    box-shadow: none;
    border: none;
    transition: all var(--md-motion-duration-medium) var(--md-motion-easing-standard);
    position: relative;
    overflow: hidden;
}

.calculator-card::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: inherit;
    background: var(--md-primary);
    opacity: 0;
    transition: opacity var(--md-motion-duration-short) var(--md-motion-easing-standard);
    pointer-events: none;
}

.calculator-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--md-elevation-1);
}

.calculator-card:hover::before {
    opacity: var(--md-state-hover-opacity);
}

.calculator-card:focus-within {
    outline: 2px solid var(--md-primary);
    outline-offset: 2px;
}

.calculator-card h3 {
    font-size: 1rem;
    font-weight: 500;
    color: var(--md-on-surface);
    margin-bottom: 6px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.calculator-card h3 .material-symbols-outlined {
    font-size: 22px;
    color: var(--md-primary);
}

.calculator-description {
    font-size: 0.875rem;
    color: var(--md-on-surface-variant);
    margin-bottom: 16px;
    line-height: 1.4;
}

/* Highlight for search results */
.calculator-card.highlight-search {
    outline: 2px solid var(--md-primary);
    outline-offset: 0;
    box-shadow: 0 0 0 4px var(--highlight-color);
}

/* Clickable Calculator Card Links */
.calculator-card-link {
    display: block;
    text-decoration: none;
    color: inherit;
    cursor: pointer;
    min-height: 100px;
}

.calculator-card-link .calculator-description {
    margin-bottom: 0;
}

.calculator-card-link:hover {
    text-decoration: none;
}

.calculator-card-link:hover h3 {
    color: var(--md-primary);
}

.calculator-card-link::after {
    content: '\e5e1';
    font-family: 'Material Symbols Outlined';
    position: absolute;
    bottom: 16px;
    right: 16px;
    font-size: 20px;
    color: var(--md-on-surface-variant);
    opacity: 0;
    transform: translateX(-8px);
    transition: all var(--md-motion-duration-medium) var(--md-motion-easing-standard);
}

.calculator-card-link:hover::after {
    opacity: 1;
    transform: translateX(0);
    color: var(--md-primary);
}

[data-theme="dark"] .calculator-card {
    background: var(--md-surface-container-high);
}

/* ==================== INPUTS (M3 Filled Text Field) ==================== */

.calculator-content {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.input-group label {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--md-on-surface-variant);
    letter-spacing: 0.02em;
}

.input-group input,
.input-group select {
    padding: 14px 16px;
    border: none;
    border-bottom: 2px solid var(--md-outline-variant);
    border-radius: var(--md-shape-xs) var(--md-shape-xs) 0 0;
    font-size: 1rem;
    font-family: inherit;
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
    background: var(--md-surface-container-highest);
    color: var(--md-on-surface);
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-bottom-color: var(--md-primary);
    border-bottom-width: 2px;
    background: var(--md-surface-container-highest);
}

.input-group input::placeholder {
    color: var(--md-on-surface-variant);
}

/* ==================== BUTTONS (M3 Filled / Outlined / Text) ==================== */

.calculate-btn,
.add-btn,
.toggle-btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--md-shape-full);
    font-size: 0.875rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
    letter-spacing: 0.02em;
    position: relative;
    overflow: hidden;
}

/* M3 Filled Button */
.calculate-btn {
    background: var(--md-primary);
    color: var(--md-on-primary);
    box-shadow: none;
}

.calculate-btn:hover {
    box-shadow: var(--md-elevation-1);
}

.calculate-btn:active {
    box-shadow: none;
}

/* M3 Outlined Button */
.add-btn {
    background: transparent;
    color: var(--md-primary);
    border: 1px solid var(--md-outline);
    margin-top: 12px;
    box-shadow: none;
}

.add-btn:hover {
    background: rgba(var(--md-primary-rgb), 0.08);
    border-color: var(--md-outline);
}

/* M3 Text Button */
.toggle-btn {
    background: transparent;
    color: var(--md-primary);
    font-size: 0.875rem;
    padding: 8px 12px;
    margin-top: 8px;
    font-weight: 500;
}

.toggle-btn:hover {
    background: rgba(var(--md-primary-rgb), 0.08);
}

/* ==================== RESULT DISPLAY ==================== */

.result {
    margin-top: 16px;
    padding: 20px;
    background: var(--md-secondary-container);
    border-radius: var(--md-shape-md);
    border-left: none;
    display: none;
}

.result.show {
    display: block;
    animation: fadeIn var(--md-motion-duration-medium) var(--md-motion-easing-decelerate);
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.result-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--md-on-secondary-container);
    margin-bottom: 8px;
}

.result-detail {
    font-size: 0.875rem;
    color: var(--md-on-secondary-container);
    opacity: 0.8;
}

/* ==================== GPA CALCULATOR ==================== */

.gpa-course-row {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 8px;
    margin-bottom: 8px;
}

.gpa-course-row input,
.gpa-course-row select {
    padding: 10px 12px;
    border: none;
    border-bottom: 1px solid var(--md-outline-variant);
    border-radius: var(--md-shape-xs) var(--md-shape-xs) 0 0;
    font-size: 0.875rem;
    font-family: inherit;
    background: var(--md-surface-container-highest);
    color: var(--md-on-surface);
}

.gpa-course-row input:focus,
.gpa-course-row select:focus {
    outline: none;
    border-bottom-color: var(--md-primary);
    border-bottom-width: 2px;
}

/* ==================== EXCHANGE RATE INFO ==================== */

.exchange-rate-info,
.crypto-rate-info {
    font-size: 0.8rem;
    color: var(--md-on-surface-variant);
    font-style: italic;
}

/* ==================== MODALS (M3 Dialog) ==================== */

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--modal-backdrop);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--md-motion-duration-medium) var(--md-motion-easing-standard),
                visibility var(--md-motion-duration-medium) var(--md-motion-easing-standard);
}

.modal.show {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background-color: var(--md-surface-container-high);
    padding: 28px;
    border-radius: var(--md-shape-xl);
    box-shadow: var(--md-elevation-3);
    max-width: 500px;
    width: 90%;
    transform: scale(0.9) translateY(20px);
    transition: transform var(--md-motion-duration-medium) var(--md-motion-easing-emphasized);
    position: relative;
    max-height: 90vh;
    overflow-y: auto;
}

.modal.show .modal-content {
    transform: scale(1) translateY(0);
}

.modal-content h3 {
    font-size: 1.25rem;
    margin-bottom: 20px;
    color: var(--md-on-surface);
    font-weight: 500;
}

.close-modal-btn {
    background: var(--md-primary);
    color: var(--md-on-primary);
    padding: 10px 24px;
    border: none;
    border-radius: var(--md-shape-full);
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 500;
    margin-top: 20px;
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
    box-shadow: none;
    letter-spacing: 0.02em;
}

.close-modal-btn:hover {
    box-shadow: var(--md-elevation-1);
}

/* Help Modal */
.help-modal-content .shortcut {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    border-bottom: 1px solid var(--md-outline-variant);
}

.help-modal-content .shortcut:last-child {
    border-bottom: none;
}

.help-modal-content .shortcut kbd {
    background: var(--md-surface-container-highest);
    color: var(--md-on-surface);
    padding: 4px 10px;
    border-radius: var(--md-shape-sm);
    font-family: 'Inter', monospace;
    font-size: 0.8rem;
    border: 1px solid var(--md-outline-variant);
    font-weight: 500;
}

/* ==================== FOOTER ==================== */

footer {
    background: var(--md-surface-container);
    padding: 48px 0 24px;
    margin-top: 0;
    border-top: none;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 32px;
    margin-bottom: 32px;
}

.footer-section h4 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--md-on-surface);
    margin-bottom: 12px;
}

.footer-section p {
    font-size: 0.875rem;
    color: var(--md-on-surface-variant);
    line-height: 1.6;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 8px;
}

.footer-section ul li a {
    color: var(--md-on-surface-variant);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color var(--md-motion-duration-short) var(--md-motion-easing-standard);
    position: relative;
}

.footer-section ul li a:hover {
    color: var(--md-primary);
}

.footer-bottom {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid var(--md-outline-variant);
}

.footer-bottom p {
    font-size: 0.8rem;
    color: var(--md-on-surface-variant);
}

/* ==================== RESPONSIVE DESIGN ==================== */

@media (max-width: 768px) {
    header {
        padding: 20px 0 12px;
        position: sticky;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .header-top {
        flex-direction: column;
        gap: 10px;
    }

    .header-controls {
        position: static;
        margin-left: 0;
        width: 100%;
        justify-content: center;
    }

    .search-bar-wrapper {
        max-width: 100%;
        width: 100%;
    }

    #header-search-input {
        max-width: 100%;
    }

    .nav-links {
        gap: 6px;
        padding: 0 12px;
    }

    .nav-link {
        padding: 6px 12px;
        font-size: 0.8rem;
    }

    .calculator-grid {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .calculator-section {
        padding: 20px 16px;
        margin-bottom: 20px;
        border-radius: var(--md-shape-lg);
    }

    .featured-section {
        padding: 32px 0;
    }

    .featured-section h2 {
        font-size: 1.5rem;
    }

    .featured-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .fraction-row {
        flex-direction: column;
        gap: 12px;
    }

    .frac-op {
        transform: rotate(90deg);
    }
}

@media (min-width: 769px) and (max-width: 1024px) {
    .calculator-grid {
        grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    }
}

/* ==================== FUN & LIFESTYLE CALCULATORS ==================== */

.full-page-link {
    display: inline-block;
    margin-top: 16px;
    color: var(--md-primary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.875rem;
    transition: color var(--md-motion-duration-short) var(--md-motion-easing-standard);
}

.full-page-link:hover {
    text-decoration: underline;
}

.calculator-card.coming-soon {
    opacity: 0.6;
    position: relative;
}

.calculator-card.coming-soon::after {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--md-surface-container);
    opacity: 0.3;
    border-radius: inherit;
    pointer-events: none;
}

.coming-soon-text {
    text-align: center;
    color: var(--md-tertiary);
    font-weight: 600;
    font-size: 1rem;
    padding: 30px 0;
}

/* Love/fun result styling */
.love-result-display {
    text-align: center;
    padding: 20px;
    background: var(--md-tertiary-container);
    border-radius: var(--md-shape-md);
    margin-top: 16px;
}

.love-score {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--md-on-tertiary-container);
    margin-bottom: 8px;
}

.love-message {
    color: var(--md-on-tertiary-container);
    font-size: 0.95rem;
}

.love-hearts {
    font-size: 1.5rem;
    margin-top: 10px;
}

/* ==================== UNIT TOGGLE ==================== */

.unit-toggle {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
    background: var(--md-surface-container-highest);
    border-radius: var(--md-shape-full);
    padding: 4px;
}

.unit-btn {
    flex: 1;
    padding: 8px 16px;
    border: none;
    background: transparent;
    color: var(--md-on-surface-variant);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    border-radius: var(--md-shape-full);
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
}

.unit-btn.active {
    background-color: var(--md-secondary-container);
    color: var(--md-on-secondary-container);
}

/* ==================== RELATED CALCULATORS ==================== */

.related-calculators {
    max-width: 700px;
    margin: 48px auto;
    padding: 0 24px;
}

.related-calculators h3 {
    text-align: center;
    font-size: 1.5rem;
    margin-bottom: 24px;
    color: var(--md-on-surface);
    font-weight: 500;
}

.related-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 16px;
}

.related-card {
    background: var(--md-surface-container-high);
    padding: 20px;
    border-radius: var(--md-shape-md);
    text-align: center;
    text-decoration: none;
    color: var(--md-on-surface);
    border: none;
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
    box-shadow: none;
}

.related-card:hover {
    box-shadow: var(--md-elevation-1);
    transform: translateY(-2px);
}

.related-card .icon {
    font-size: 2rem;
    margin-bottom: 10px;
}

.related-card .title {
    font-weight: 500;
    margin-bottom: 6px;
    font-size: 0.95rem;
}

.related-card .desc {
    font-size: 0.8rem;
    color: var(--md-on-surface-variant);
}

/* ==================== RIPPLE EFFECT (M3) ==================== */

.ripple-effect {
    position: relative;
    overflow: hidden;
    transform: translate3d(0, 0, 0);
}

.ripple-effect .ripple {
    display: block;
    position: absolute;
    border-radius: 50%;
    background: rgba(var(--md-on-surface-rgb), 0.12);
    transform: scale(0);
    opacity: 1;
    animation: ripple-animation 0.6s linear;
    pointer-events: none;
}

@keyframes ripple-animation {
    from {
        transform: scale(0);
        opacity: 1;
    }
    to {
        transform: scale(4);
        opacity: 0;
    }
}

/* M3 icon sizing in card headers */
.calculator-card h3 .material-symbols-outlined {
    vertical-align: middle;
    font-size: 22px;
    margin-right: 6px;
}

/* ==================== SCROLLBAR (M3 Style) ==================== */

::-webkit-scrollbar {
    width: 8px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--md-outline-variant);
    border-radius: var(--md-shape-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--md-outline);
}

/* ==================== SELECTION ==================== */

::selection {
    background: var(--md-primary-container);
    color: var(--md-on-primary-container);
}

/* ==================== FOCUS VISIBLE (Accessibility) ==================== */

:focus-visible {
    outline: 2px solid var(--md-primary);
    outline-offset: 2px;
}

button:focus-visible,
a:focus-visible {
    outline: 2px solid var(--md-primary);
    outline-offset: 2px;
}

/* =====================================================
   SUBPAGE COMPONENTS (M3 Design Language)
   Applied to all calculator/info pages
   ===================================================== */

/* ==================== SITE HEADER (Subpages) ==================== */

.site-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 24px;
    background: var(--md-surface-container);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: box-shadow var(--md-motion-duration-medium) var(--md-motion-easing-standard);
}

.site-header.scrolled {
    box-shadow: var(--md-elevation-2);
}

.site-header .logo {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--md-primary);
    text-decoration: none;
    letter-spacing: -0.01em;
}

.site-header .logo:hover {
    opacity: 0.85;
}

.site-header .header-controls {
    display: flex;
    gap: 4px;
    align-items: center;
    margin-left: 0;
}

/* ==================== BREADCRUMB (M3 Style) ==================== */

.breadcrumb {
    padding: 12px 24px;
    background: var(--md-surface-container-low);
    border-bottom: none;
    font-size: 0.85rem;
}

.breadcrumb a {
    color: var(--md-primary);
    text-decoration: none;
    font-weight: 500;
}

.breadcrumb a:hover {
    text-decoration: underline;
}

.breadcrumb span {
    color: var(--md-on-surface-variant);
    margin: 0 8px;
}

/* ==================== HERO SECTION (Subpages - M3 Tonal) ==================== */

.hero,
.page-header,
.about-hero,
.privacy-hero,
.article-header {
    text-align: center;
    padding: 48px 24px;
    background: var(--md-primary-container);
    color: var(--md-on-primary-container);
    position: static;
    z-index: auto;
}

.hero h1,
.page-header h1,
.about-hero h1 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--md-on-primary-container);
    letter-spacing: -0.02em;
}

.hero p,
.page-header p,
.about-hero p {
    font-size: 1rem;
    opacity: 0.85;
    max-width: 600px;
    margin: 0 auto;
    color: var(--md-on-primary-container);
}

/* ==================== CALCULATOR CONTAINER (Subpages) ==================== */

.calculator-container {
    max-width: 560px;
    margin: -32px auto 40px;
    padding: 0 20px;
    position: relative;
    z-index: 10;
}

.calculator-container .calculator-card {
    background: var(--md-surface-container-low);
    border-radius: var(--md-shape-xl);
    box-shadow: var(--md-elevation-2);
    padding: 32px;
    border: none;
    overflow: visible;
}

.calculator-container .calculator-card::before {
    display: none;
}

.calculator-container .calculator-card .input-group {
    margin-bottom: 16px;
}

.calculator-container .calculator-card .input-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 6px;
    color: var(--md-on-surface-variant);
    font-size: 0.85rem;
    letter-spacing: 0.02em;
}

.calculator-container .calculator-card .input-group input,
.calculator-container .calculator-card .input-group select {
    width: 100%;
    padding: 14px 16px;
    border: none;
    border-bottom: 2px solid var(--md-outline-variant);
    border-radius: var(--md-shape-xs) var(--md-shape-xs) 0 0;
    background: var(--md-surface-container-highest);
    color: var(--md-on-surface);
    font-size: 1rem;
    font-family: inherit;
    transition: border-color var(--md-motion-duration-short) var(--md-motion-easing-standard);
}

.calculator-container .calculator-card .input-group input:focus,
.calculator-container .calculator-card .input-group select:focus {
    outline: none;
    border-bottom-color: var(--md-primary);
}

.calculator-container .calculate-btn {
    width: 100%;
    padding: 14px 24px;
    font-size: 1rem;
    font-weight: 500;
    background: var(--md-primary);
    color: var(--md-on-primary);
    border: none;
    border-radius: var(--md-shape-full);
    cursor: pointer;
    letter-spacing: 0.02em;
    transition: box-shadow var(--md-motion-duration-short) var(--md-motion-easing-standard);
    margin-top: 8px;
}

.calculator-container .calculate-btn:hover {
    box-shadow: var(--md-elevation-1);
}

.calculator-container .result-container {
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--md-outline-variant);
}

.calculator-container .result-container.show {
    display: block;
    animation: fadeIn var(--md-motion-duration-medium) var(--md-motion-easing-decelerate);
}

/* ==================== INPUT ROW (Multi-field layout) ==================== */

.input-row {
    display: flex;
    gap: 12px;
    margin-bottom: 16px;
}

.input-row .input-group {
    flex: 1;
    margin-bottom: 0;
}

/* ==================== CONTENT SECTIONS (Educational content) ==================== */

.content-section {
    max-width: 840px;
    margin: 48px auto;
    padding: 0 24px;
}

.content-section h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--md-on-surface);
    border-bottom: none;
    padding-bottom: 0;
}

.content-section h3 {
    font-size: 1.15rem;
    font-weight: 500;
    margin: 28px 0 12px;
    color: var(--md-on-surface);
}

.content-section p {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--md-on-surface-variant);
    margin-bottom: 12px;
}

.content-section ul,
.content-section ol {
    margin: 12px 0;
    padding-left: 24px;
}

.content-section li {
    margin-bottom: 8px;
    line-height: 1.6;
    color: var(--md-on-surface-variant);
    font-size: 0.95rem;
}

.content-section li strong {
    color: var(--md-on-surface);
}

/* ==================== INFO GRID & CARDS ==================== */

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 16px;
    margin: 24px 0;
}

.info-card {
    background: var(--md-surface-container);
    border-radius: var(--md-shape-md);
    padding: 20px;
    border: none;
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
}

.info-card:hover {
    box-shadow: var(--md-elevation-1);
    transform: translateY(-2px);
}

.info-card h4 {
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 10px;
    color: var(--md-on-surface);
    display: flex;
    align-items: center;
    gap: 8px;
}

.info-card p {
    font-size: 0.875rem;
    color: var(--md-on-surface-variant);
    line-height: 1.6;
}

/* ==================== HIGHLIGHT BOX (M3 Tonal) ==================== */

.highlight-box {
    background: var(--md-tertiary-container);
    border-left: none;
    padding: 20px 24px;
    border-radius: var(--md-shape-md);
    margin: 24px 0;
}

.highlight-box h4 {
    color: var(--md-on-tertiary-container);
    margin-bottom: 8px;
    font-weight: 500;
}

.highlight-box p {
    color: var(--md-on-tertiary-container);
    opacity: 0.9;
}

/* ==================== FAQ ITEMS (M3 Style) ==================== */

.faq-section {
    max-width: 700px;
    margin: 48px auto;
    padding: 0 24px;
}

.faq-item {
    margin-bottom: 12px;
    padding: 20px;
    background: var(--md-surface-container);
    border-radius: var(--md-shape-md);
    border: none;
    border-bottom: none;
    padding-bottom: 20px;
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-item h4 {
    font-size: 1rem;
    font-weight: 500;
    color: var(--md-on-surface);
    margin-bottom: 8px;
}

.faq-item p {
    font-size: 0.875rem;
    color: var(--md-on-surface-variant);
    line-height: 1.6;
}

/* ==================== TIPS LIST ==================== */

.tips-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
    margin: 24px 0;
}

.tip-item {
    background: var(--md-surface-container);
    padding: 20px;
    border-radius: var(--md-shape-md);
    border: none;
    font-size: 0.875rem;
    color: var(--md-on-surface-variant);
    line-height: 1.6;
}

.tip-item strong {
    color: var(--md-on-surface);
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
}

/* ==================== DATA TABLES (M3 Style) ==================== */

.bmi-table,
.mortgage-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    margin: 20px 0;
    background: var(--md-surface-container);
    border-radius: var(--md-shape-md);
    overflow: hidden;
    font-size: 0.9rem;
}

.bmi-table th,
.mortgage-table th {
    padding: 14px 16px;
    text-align: left;
    background: var(--md-primary);
    color: var(--md-on-primary);
    font-weight: 500;
    font-size: 0.85rem;
    letter-spacing: 0.02em;
}

.bmi-table td,
.mortgage-table td {
    padding: 12px 16px;
    border-bottom: 1px solid var(--md-outline-variant);
    color: var(--md-on-surface-variant);
}

.bmi-table tr:last-child td,
.mortgage-table tr:last-child td {
    border-bottom: none;
}

.bmi-table tr:hover td,
.mortgage-table tr:hover td {
    background: var(--md-surface-container-high);
}

/* ==================== FEEDBACK SECTION ==================== */

.feedback-section {
    max-width: 560px;
    margin: 40px auto;
    padding: 28px;
    background: var(--md-surface-container);
    border-radius: var(--md-shape-xl);
    text-align: center;
    border: none;
}

.feedback-section h4 {
    margin-bottom: 12px;
    color: var(--md-on-surface);
    font-weight: 500;
}

.rating-stars {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin: 12px 0;
    font-size: 1.5rem;
    cursor: pointer;
}

.rating-stars span {
    color: var(--md-outline);
    transition: color var(--md-motion-duration-short) var(--md-motion-easing-standard);
}

.rating-stars span:hover,
.rating-stars span.active {
    color: #FFC107;
}

/* ==================== HOW IT WORKS SECTION ==================== */

.how-it-works {
    max-width: 1200px;
    margin: 48px auto;
    padding: 0 24px;
}

.how-it-works h2 {
    text-align: center;
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 24px;
    color: var(--md-on-surface);
}

.how-it-works-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
}

.how-card {
    background: var(--md-surface-container);
    border-radius: var(--md-shape-md);
    padding: 24px;
    border: none;
    transition: all var(--md-motion-duration-short) var(--md-motion-easing-standard);
}

.how-card:hover {
    box-shadow: var(--md-elevation-1);
    transform: translateY(-2px);
}

.how-icon {
    font-size: 2rem;
    margin-bottom: 12px;
}

.how-card h3 {
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 10px;
    color: var(--md-on-surface);
    text-align: left;
}

.how-card p {
    font-size: 0.85rem;
    line-height: 1.6;
    color: var(--md-on-surface-variant);
}

/* ==================== BMI DISPLAY (Result display) ==================== */

.bmi-display {
    text-align: center;
    padding: 32px;
    background: var(--md-primary-container);
    color: var(--md-on-primary-container);
    border-radius: var(--md-shape-lg);
    margin-bottom: 16px;
}

.bmi-value {
    font-size: 3rem;
    font-weight: 700;
    color: var(--md-on-primary-container);
}

.bmi-category {
    font-size: 1.25rem;
    opacity: 0.85;
    margin-top: 8px;
    color: var(--md-on-primary-container);
}

.category-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
    margin-top: 16px;
}

.cat-item {
    padding: 12px;
    background: var(--md-surface-container-highest);
    border-radius: var(--md-shape-sm);
    text-align: center;
    font-size: 0.85rem;
    color: var(--md-on-surface-variant);
}

.cat-value {
    font-weight: 600;
    color: var(--md-primary);
    margin-bottom: 4px;
}

/* ==================== SEARCH MODAL (Subpages) ==================== */

.search-modal-content {
    padding: 16px;
}

.search-modal-content input {
    width: 100%;
    padding: 14px 16px;
    border: none;
    border-bottom: 2px solid var(--md-outline-variant);
    border-radius: var(--md-shape-xs) var(--md-shape-xs) 0 0;
    background: var(--md-surface-container-highest);
    color: var(--md-on-surface);
    font-size: 1rem;
    font-family: inherit;
}

.search-modal-content input:focus {
    outline: none;
    border-bottom-color: var(--md-primary);
}

.search-hint {
    text-align: center;
    font-size: 0.8rem;
    color: var(--md-on-surface-variant);
    margin-top: 12px;
}

.search-hint kbd {
    background: var(--md-surface-container-highest);
    padding: 2px 6px;
    border-radius: var(--md-shape-xs);
    font-size: 0.75rem;
    border: 1px solid var(--md-outline-variant);
}

/* ==================== SUBPAGE RESPONSIVE ==================== */

@media (max-width: 768px) {
    .site-header {
        padding: 10px 16px;
    }

    .site-header .logo {
        font-size: 1.1rem;
    }

    .hero,
    .page-header,
    .about-hero {
        padding: 36px 20px;
    }

    .hero h1,
    .page-header h1,
    .about-hero h1 {
        font-size: 1.5rem;
    }

    .calculator-container {
        margin: -20px auto 30px;
    }

    .calculator-container .calculator-card {
        padding: 24px;
        border-radius: var(--md-shape-lg);
    }

    .content-section {
        margin: 32px auto;
    }

    .info-grid {
        grid-template-columns: 1fr;
    }

    .input-row {
        flex-direction: column;
        gap: 8px;
    }

    .category-grid {
        grid-template-columns: 1fr 1fr;
    }

    .bmi-value {
        font-size: 2.5rem;
    }
}