/*
    Handbook CSS - A Professional Refactor
    ---------------------------------------------
    This stylesheet has been completely rewritten with a modern,
    component-based architecture using CSS Custom Properties for a
    scalable and maintainable design system. The visual and
    interactive experience remains identical to the original, with
    key improvements to UI and readability.
*/

/* ==========================================================================
   1. FOUNDATION & DESIGN TOKENS
   ========================================================================== */

/* --- Font Import --- */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;600;700&display=swap');

:root {
    /* Base Palette (Light Mode) */
    --c-bg: #EFF2F5; /* Darkened */
    --c-surface: #FFFFFF;
    --c-text-primary: #1a1a1a;
    --c-text-secondary: #5a646e;
    --c-accent: #0077ff;
    --c-border: #e9ecef;
    --c-shadow-color: rgba(0, 4, 48, 0.05);

    /* UI Feedback Colors */
    --c-success: #28a745;
    --c-error: #dc3545;
    --c-info: #17a2b8;
    --c-light-text-on-accent: #ffffff;
    
    /* Typography */
    --font-primary: 'Poppins', sans-serif;
    --fw-regular: 400;
    --fw-semibold: 600;
    --fw-bold: 700;

    /* Spacing & Sizing */
    --space-xs: 0.5rem;   /* 8px */
    --space-sm: 0.75rem;  /* 12px */
    --space-md: 1rem;     /* 16px */
    --space-lg: 1.5rem;   /* 24px */
    --space-xl: 2rem;     /* 32px */
    --space-xxl: 2.5rem;  /* 40px */
    
    /* Borders & Radii */
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-full: 50px;
    --border-width: 1px;

    /* Shadows */
    --shadow-sm: 0 4px 15px var(--c-shadow-color);
    --shadow-md: 0 8px 30px var(--c-shadow-color);
    --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.2);

    /* Transitions */
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-medium: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-playful: 0.5s cubic-bezier(0.34, 1.56, 0.64, 1); /* Faster */
}

/* --- Global Styles --- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    background: var(--c-bg);
    color: var(--c-text-primary);
    transition: background 0.5s ease, color 0.5s ease, background-image 0.5s ease;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background-attachment: fixed;
    padding-bottom: calc(60px + env(safe-area-inset-bottom)); /* Space for fixed footer */
}

h1, h2, h3 {
    font-weight: var(--fw-bold);
    color: var(--c-text-primary);
}

p {
    color: var(--c-text-secondary);
    line-height: 1.6;
}

a {
    color: var(--c-accent);
    text-decoration: none;
    transition: opacity var(--transition-fast);
}

a:hover {
    opacity: 0.8;
}

input, button {
    font-family: inherit;
    font-size: inherit;
    color: inherit;
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible {
    outline: 3px solid color-mix(in srgb, var(--c-accent) 70%, white 10%);
    outline-offset: 2px;
}

/* ==========================================================================
   2. THEMES (REFINED & DARKENED)
   ========================================================================== */

body.dark-mode {
    --c-bg: #0d0d0d; --c-surface: #222222; --c-text-primary: #EAEAEA;
    --c-text-secondary: #888888; --c-accent: #00A6ED; --c-border: #333333;
    --c-shadow-color: rgba(0, 0, 0, 0.2);
}
body.cream-mode {
    --c-bg: #F1ECCD; --c-surface: #FFF9E7; --c-text-primary: #6B4F4F;
    --c-text-secondary: #9E8B7D; --c-accent: #C19A6B; --c-border: #EFE8D0;
    --c-shadow-color: rgba(107, 79, 79, 0.08);
}
body.pop-blue-mode {
    --c-bg: #DDEBE8; --c-surface: #ffffff; --c-text-primary: #1D3557;
    --c-text-secondary: #457B9D; --c-accent: #E63946; --c-border: #a8dadc4d;
    --c-shadow-color: rgba(29, 53, 87, 0.08);
}
body.pop-green-mode {
    --c-bg: #D9F2E1; --c-surface: #ffffff; --c-text-primary: #004D40;
    --c-text-secondary: #006A57; --c-accent: #FF6B6B; --c-border: #b2f7c24d;
    --c-shadow-color: rgba(0, 77, 64, 0.08);
}
body.sunset-mode {
    --c-bg: #F5E8DA; --c-surface: #ffffff; --c-text-primary: #5E376D;
    --c-text-secondary: #A16A70; --c-accent: #FF7B54; --c-border: #ffecd94d;
    --c-shadow-color: rgba(94, 55, 109, 0.08);
}
body.midnight-mode {
    --c-bg: #0B111F; --c-surface: #1E293B; --c-text-primary: #E2E8F0;
    --c-text-secondary: #94A3B8; --c-accent: #818CF8; --c-border: #334155;
    --c-shadow-color: rgba(0, 0, 0, 0.2);
}

/* --- Gradient Themes --- */
body.sunny-meadow-mode {
    --c-bg: #F5EDD8;
    --c-surface: #FFFFFF;
    --c-text-primary: #5c5221;
    --c-text-secondary: #857c58;
    --c-accent: #E07A5F;
    --c-border: #f2e9c2;
    --c-shadow-color: rgba(107, 79, 79, 0.08);
    background-image: linear-gradient(160deg, rgba(246, 211, 101, 0.2) 0%, rgba(253, 160, 133, 0.15) 100%);
}
body.ocean-breeze-mode {
    --c-bg: #D9EFF1;
    --c-surface: #FFFFFF;
    --c-text-primary: #0b4f6c;
    --c-text-secondary: #247b7b;
    --c-accent: #17A2B8;
    --c-border: #cceef2;
    --c-shadow-color: rgba(29, 53, 87, 0.08);
    background-image: linear-gradient(160deg, rgba(91, 36, 122, 0.1) 0%, rgba(27, 206, 223, 0.15) 100%);
}
body.starry-night-mode {
    --c-bg: #15252b;
    --c-surface: rgba(255, 255, 255, 0.08);
    --c-text-primary: #ffffff;
    --c-text-secondary: rgba(255, 255, 255, 0.7);
    --c-border: rgba(255, 255, 255, 0.15);
    --c-shadow-color: rgba(0, 0, 0, 0.25);
    --c-accent: #a3bded;
    background-image: linear-gradient(135deg, rgba(15, 32, 39, 0.5) 0%, rgba(32, 58, 67, 0.7) 50%, rgba(44, 83, 100, 0.7) 100%);
}


/* ==========================================================================
   3. LAYOUT
   ========================================================================== */
.page-container {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    animation: fadeIn 0.5s ease-in-out;
}

.page-main-content {
    padding: 100px var(--space-xl) var(--space-xl) var(--space-xl);
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--space-xxl);
}

.page-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: var(--space-md);
}

#home-page main {
    flex-grow: 1;
    display: flex;
    justify-content: center;
    text-align: center;
    padding: 100px var(--space-xl) var(--space-xl);
}

.home-content {
    width: min(100%, 760px);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xl);
    transition: transform 760ms cubic-bezier(0.19, 0.86, 0.28, 1);
}

#home-page footer {
    padding: var(--space-xl);
    width: 100%;
    max-width: 880px;
    margin: 0 auto;
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

#home-page.results-visible .home-content {
    transform: translateY(-52px);
}

/* ==========================================================================
   4. COMPONENTS
   ========================================================================== */

/* --- Header & Theme Manager --- */
header {
    position: fixed;
    top: 20px;
    left: 20px;
    right: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 44px;
    z-index: 100;
    transition: transform var(--transition-medium);
}
header.header-hidden {
    transform: translateY(calc(-100% - 30px));
}
.header-nav {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    background-color: color-mix(in srgb, var(--c-surface) 80%, transparent);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-full);
    box-shadow: var(--shadow-sm);
    border: var(--border-width) solid var(--c-border);
    padding: 4px;
}
#theme-manager {
    display: flex;
    align-items: center;
    background-color: color-mix(in srgb, var(--c-surface) 80%, transparent);
    backdrop-filter: blur(10px);
    border-radius: var(--radius-full);
    box-shadow: var(--shadow-sm);
    border: var(--border-width) solid var(--c-border);
    transition: all var(--transition-playful);
}
.theme-switcher {
    display: flex;
    gap: var(--space-xs);
    padding: 0 var(--space-xs);
    max-width: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-width var(--transition-medium), opacity 0.2s ease, padding var(--transition-medium);
}
#theme-manager.themes-visible .theme-switcher {
    max-width: 450px;
    opacity: 1;
    padding: var(--space-xs);
}
.theme-switcher button {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: 2px solid var(--c-border);
    cursor: pointer;
    transition: all var(--transition-playful);
    flex-shrink: 0;
}
.theme-switcher button:hover {
    transform: scale(1.15) rotate(15deg);
}
.theme-switcher button.active {
    border-color: var(--c-accent);
    transform: scale(1.25) rotate(-5deg);
    box-shadow: 0 0 12px color-mix(in srgb, var(--c-accent) 60%, transparent);
}
#toggle-themes-btn .arrow-icon {
    transition: transform var(--transition-medium);
}
#theme-manager.themes-visible .arrow-icon {
    transform: rotate(180deg);
}
#light-btn { background-color: #EFF2F5; }
#dark-btn  { background-color: #0d0d0d; }
#cream-btn { background-color: #F1ECCD; }
#pop-blue-btn { background-color: #DDEBE8; }
#pop-green-btn { background-color: #D9F2E1; }
#sunset-btn { background-color: #F5E8DA; }
#midnight-btn { background-color: #0B111F; }
#sunny-meadow-btn { background: linear-gradient(160deg, rgba(246, 211, 101, 0.8), rgba(253, 160, 133, 0.8)); }
#ocean-breeze-btn { background: linear-gradient(160deg, rgba(91, 36, 122, 0.8), rgba(27, 206, 223, 0.8)); }
#starry-night-btn { background: linear-gradient(135deg, #0f2027, #2c5364); }

/* --- Buttons --- */
.icon-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    color: var(--c-text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color var(--transition-fast), transform var(--transition-fast);
}
.icon-btn svg {
    stroke: currentColor;
}
.icon-btn:hover {
    color: var(--c-accent);
    transform: scale(1.1);
}
.icon-btn:active {
    transform: scale(1);
}
.icon-btn:focus-visible {
    border-radius: 999px;
}

/* --- Card --- */
.card {
    background-color: var(--c-surface);
    border-radius: var(--radius-lg);
    border: var(--border-width) solid var(--c-border);
    padding: var(--space-lg);
    transition: all var(--transition-medium);
}

/* --- Logo & SOTD --- */
.logo-container {
    cursor: pointer;
    transition: transform var(--transition-playful);
    animation: popIn 0.8s var(--transition-playful) backwards;
    margin-bottom: var(--space-xl);
}
.logo-container:active {
    transform: scale(0.95) rotate(-3deg);
}
.main-icon {
    fill: var(--c-accent);
    transition: fill var(--transition-medium);
    margin-bottom: var(--space-xs);
}
.logo-container h1 {
    font-size: clamp(2.5rem, 8vw, 3.5rem);
    font-weight: var(--fw-bold);
}
.logo-container:hover .main-icon {
    fill: var(--c-text-primary);
}
.sotd-wrapper {
    margin-top: -1rem;
    margin-bottom: var(--space-xl);
    display: grid;
    place-items: center;
    animation: fadeIn 1s 0.5s ease backwards;
    transition: transform 760ms cubic-bezier(0.19, 0.86, 0.28, 1);
}
.sotd-label {
    font-size: 0.8rem;
    font-weight: var(--fw-semibold);
    color: var(--c-text-secondary);
    margin-bottom: var(--space-xs);
    letter-spacing: 0.5px;
}
#sotd-card, .flashcard-container {
    width: 100%;
    perspective: 1500px;
    cursor: pointer;
}
#sotd-card:focus-visible {
    outline: none;
}
#sotd-card:focus-visible .sotd-card-inner {
    box-shadow: 0 0 0 3px color-mix(in srgb, var(--c-accent) 50%, transparent);
    border-radius: var(--radius-lg);
}
#sotd-card { max-width: 320px; height: 80px; }
#sotd-card .sotd-card-inner, .flashcard-container .flashcard {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.6s cubic-bezier(0.45, 0, 0.55, 1); /* Faster, smoother flip */
    transform-style: preserve-3d;
}
#sotd-card.is-flipped .sotd-card-inner, .flashcard-container.is-flipped .flashcard {
    transform: rotateY(180deg);
}
.sotd-front, .sotd-back, .flashcard-front, .flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    inset: 0;
    backface-visibility: hidden;
    display: grid;
    place-content: center;
    padding: var(--space-xl);
    border-radius: var(--radius-lg);
    background: var(--c-surface);
    border: var(--border-width) solid var(--c-border);
    box-shadow: var(--shadow-md);
    text-align: center;
}
.sotd-back, .flashcard-back {
    transform: rotateY(180deg);
}
#sotd-name { font-size: 1.2rem; font-weight: var(--fw-semibold); }
#sotd-desc { font-size: 0.9rem; }

/* --- ASL Recognizer --- */
.asl-recognizer {
    width: 100%;
    max-width: 680px;
    text-align: left;
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    animation: fadeIn 0.8s 0.3s ease backwards;
}

.recognizer-header h2 {
    font-size: 1.35rem;
    margin-bottom: 0.2rem;
}

.recognizer-header p {
    font-size: 0.92rem;
}

.recognizer-stage {
    position: relative;
    width: 100%;
    aspect-ratio: 4 / 3;
    border-radius: var(--radius-md);
    border: var(--border-width) solid var(--c-border);
    overflow: hidden;
    background: radial-gradient(circle at 20% 20%, color-mix(in srgb, var(--c-accent) 12%, var(--c-surface)), var(--c-surface));
}

#asl-video {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transform: scaleX(-1);
}

#asl-overlay-canvas {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    transform: scaleX(-1);
}

.recognizer-placeholder {
    position: absolute;
    inset: 0;
    display: grid;
    place-items: center;
    color: var(--c-text-secondary);
    font-weight: var(--fw-semibold);
    background-color: color-mix(in srgb, var(--c-surface) 88%, transparent);
    transition: opacity var(--transition-fast);
}

.recognizer-placeholder.hidden {
    opacity: 0;
    pointer-events: none;
}

#asl-preview-canvas {
    display: none;
}

.recognizer-status {
    font-size: 0.9rem;
    color: var(--c-text-secondary);
    min-height: 1.4em;
}

.recognizer-status[data-kind="success"] {
    color: var(--c-success);
}

.recognizer-status[data-kind="error"] {
    color: var(--c-error);
}

.recognizer-result {
    font-size: 1.05rem;
    font-weight: var(--fw-semibold);
    color: var(--c-text-primary);
    min-height: 1.4em;
}

.recognizer-controls {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: var(--space-sm);
}

.recognizer-topk {
    border: var(--border-width) solid color-mix(in srgb, var(--c-border) 80%, transparent);
    border-radius: var(--radius-md);
    padding: 0.65rem 0.8rem;
    background-color: color-mix(in srgb, var(--c-surface) 88%, transparent);
}

.topk-title {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-weight: var(--fw-bold);
    margin-bottom: 0.45rem;
}

.topk-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    margin: 0;
    padding: 0;
}

.topk-item {
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: center;
    gap: 0.6rem;
    font-size: 0.86rem;
}

.topk-label {
    min-width: 0;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.topk-value {
    color: var(--c-text-secondary);
    font-variant-numeric: tabular-nums;
}

.recognizer-calibration {
    margin-top: 0.25rem;
    padding-top: 0.75rem;
    border-top: 1px dashed color-mix(in srgb, var(--c-border) 70%, transparent);
    display: flex;
    flex-direction: column;
    gap: 0.55rem;
}

.recognizer-mode {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.mode-label {
    font-size: 0.82rem;
    color: var(--c-text-secondary);
    font-weight: var(--fw-semibold);
}

.calibration-title {
    font-size: 0.82rem;
    font-weight: var(--fw-bold);
    letter-spacing: 0.02em;
    text-transform: uppercase;
}

.calibration-controls {
    display: flex;
    gap: var(--space-sm);
    flex-wrap: wrap;
}

.calibration-select {
    min-width: 160px;
    border: var(--border-width) solid var(--c-border);
    border-radius: var(--radius-full);
    background-color: var(--c-surface);
    color: var(--c-text-primary);
    padding: 0.55rem 0.95rem;
    font-size: 0.9rem;
    outline: none;
}

.calibration-select:focus {
    border-color: var(--c-accent);
    box-shadow: 0 0 0 3px color-mix(in srgb, var(--c-accent) 20%, transparent);
}

.calibration-status {
    font-size: 0.82rem;
    color: var(--c-text-secondary);
}

.recognizer-btn {
    border: var(--border-width) solid var(--c-border);
    background-color: var(--c-surface);
    color: var(--c-text-primary);
    border-radius: var(--radius-full);
    padding: 0.7rem 1rem;
    font-size: 0.9rem;
    font-weight: var(--fw-semibold);
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 2.6rem;
}

.recognizer-btn.primary {
    background-color: var(--c-accent);
    border-color: var(--c-accent);
    color: var(--c-light-text-on-accent);
}

.recognizer-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
    border-color: var(--c-accent);
}

.recognizer-btn:disabled {
    opacity: 0.55;
    cursor: not-allowed;
    box-shadow: none;
    transform: none;
}

.recognizer-btn.hidden {
    display: none;
}


/* --- Search --- */
.search-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-sm);
}
.search-helper {
    font-size: 0.9rem;
    color: var(--c-text-secondary);
    margin-bottom: var(--space-xs);
    transition: all var(--transition-fast);
}
.search-helper.hidden {
    opacity: 0;
}
.search-form {
    position: relative;
    width: 100%;
}
.search-form input, .language-search-container input {
    width: 100%;
    padding: var(--space-md) 1.75rem;
    font-size: 1rem;
    background-color: var(--c-surface);
    border: var(--border-width) solid var(--c-border);
    border-radius: var(--radius-full);
    outline: none;
    transition: all var(--transition-medium);
}
.search-form input {
    padding-right: 10.4rem;
}
.search-form input::placeholder, .language-search-container input::placeholder {
    color: var(--c-text-secondary);
    opacity: 0.7;
}
.search-form input:focus, .language-search-container input:focus {
    border-color: var(--c-accent);
    box-shadow: 0 0 0 4px color-mix(in srgb, var(--c-accent) 20%, transparent);
}
.search-clear-btn {
    position: absolute;
    right: 6rem;
    top: 50%;
    transform: translateY(-50%);
    opacity: 0;
    pointer-events: none;
    transition: all var(--transition-fast);
}
.search-clear-btn.visible {
    opacity: 1;
    transform: translateY(-50%) scale(1);
    pointer-events: auto;
}
.language-search-container {
    width: 100%;
    max-height: 0;
    opacity: 0;
    transform: translateY(-10px);
    transition: all var(--transition-medium);
    overflow: hidden;
}
.language-search-container.visible {
    max-height: 100px;
    opacity: 1;
    transform: translateY(0);
}

.search-submit-btn {
    position: absolute;
    right: 0.45rem;
    top: 50%;
    transform: translateY(-50%);
    border: none;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--c-accent), color-mix(in srgb, var(--c-accent) 65%, black 12%));
    color: var(--c-light-text-on-accent);
    font-size: 0.85rem;
    font-weight: var(--fw-semibold);
    letter-spacing: 0.01em;
    padding: 0.56rem 1.02rem;
    cursor: pointer;
    transition: transform var(--transition-fast), box-shadow var(--transition-fast), opacity var(--transition-fast);
}

.search-submit-btn:hover {
    transform: translateY(-50%) translateX(-1px);
    box-shadow: 0 8px 16px -10px color-mix(in srgb, var(--c-accent) 85%, black 10%);
}

.search-submit-btn:active {
    transform: translateY(-50%);
}

.search-demo-results {
    width: 100%;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
    gap: var(--space-md);
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    transform: translateY(20px);
    transition:
        max-height 760ms cubic-bezier(0.19, 0.86, 0.28, 1),
        opacity 420ms ease,
        transform 760ms cubic-bezier(0.19, 0.86, 0.28, 1);
}

.search-demo-results.is-populated {
    max-height: 1100px;
    opacity: 1;
    transform: translateY(0);
}

.search-demo-card {
    position: relative;
    border-radius: var(--radius-md);
    border: var(--border-width) solid var(--c-border);
    background-color: var(--c-surface);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    min-height: 250px;
    opacity: 0;
    transform: translateY(24px);
}

.search-demo-results.is-populated .search-demo-card {
    animation: cardReveal 760ms cubic-bezier(0.16, 0.84, 0.27, 1) both;
    animation-delay: calc(var(--card-index, 0) * 95ms);
}

.search-demo-results.is-populated .search-demo-card::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(
        112deg,
        transparent 0%,
        color-mix(in srgb, var(--c-accent) 34%, transparent) 45%,
        transparent 100%
    );
    transform: translateX(-120%);
    animation: cardSweep 700ms ease-out both;
    animation-delay: calc(var(--card-index, 0) * 95ms + 120ms);
    pointer-events: none;
}

.search-demo-media {
    aspect-ratio: 16 / 10;
    background: radial-gradient(circle at 20% 20%, color-mix(in srgb, var(--c-accent) 24%, var(--c-surface)), var(--c-surface));
}

.search-demo-video {
    width: 100%;
    height: 100%;
    display: block;
    object-fit: cover;
    background-color: #111827;
}

.search-demo-lower {
    border-top: var(--border-width) solid color-mix(in srgb, var(--c-border) 70%, transparent);
    background: linear-gradient(
        180deg,
        color-mix(in srgb, var(--c-surface) 100%, transparent) 0%,
        color-mix(in srgb, var(--c-bg) 55%, var(--c-surface) 45%) 100%
    );
    padding: 0.75rem 0.85rem 0.95rem;
    min-height: 110px;
}

.search-demo-title {
    font-size: 0.82rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 0.35rem;
}

.search-demo-text {
    font-size: 0.85rem;
    line-height: 1.4;
}

/* --- Footer Links --- */
.footer-links {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--space-md);
    margin-top: var(--space-xl);
}
.footer-link-btn {
    font-size: 0.8rem;
    font-weight: var(--fw-semibold);
    padding: 0.6rem 1.2rem;
    border-radius: var(--radius-full);
    background-color: var(--c-surface);
    color: var(--c-text-secondary);
    border: var(--border-width) solid var(--c-border);
    transition: all var(--transition-fast);
}
.footer-link-btn:hover {
    background-color: var(--c-accent);
    color: var(--c-light-text-on-accent);
    border-color: var(--c-accent);
    transform: translateY(-2px);
    box-shadow: 0 4px 10px var(--c-shadow-color);
}
.footer-link-btn:active {
    transform: translateY(-1px);
}

/* --- Account Page Components --- */
.account-profile { display: flex; align-items: center; gap: var(--space-lg); }
.account-avatar {
    width: 80px; height: 80px;
    border-radius: 50%; background-color: var(--c-accent);
    color: var(--c-light-text-on-accent); display: grid; place-content: center;
    font-size: 2rem; font-weight: var(--fw-bold); flex-shrink: 0;
    transition: background-color var(--transition-medium);
}
.account-name { font-size: 2.25rem; margin-bottom: 0.25rem; }
.membership-date { font-size: 0.9rem; }

.subscription-box-link { display: flex; justify-content: space-between; align-items: center; }
.manage-sub-button {
    font-weight: var(--fw-semibold); font-size: 0.9rem;
    padding: 0.75rem 1.25rem; border-radius: var(--radius-full);
    color: var(--c-accent); border: var(--border-width) solid var(--c-accent);
}
.manage-sub-button:hover { background-color: var(--c-accent); color: var(--c-light-text-on-accent); opacity: 1; }
.manage-sub-button:active { transform: scale(0.97); }

.stats-container { display: flex; justify-content: center; gap: clamp(2rem, 10vw, 4rem); text-align: center; }
.stat-item { cursor: pointer; transition: transform var(--transition-fast); }
.stat-item:hover { transform: translateY(-5px); }
.stat-number { font-size: 2.5rem; font-weight: var(--fw-bold); color: var(--c-accent); transition: color var(--transition-medium); }
.stat-item:hover .stat-number { color: var(--c-text-primary); }
.stat-label { font-size: 0.9rem; }

/* --- [MODERNIZED] Group Management --- */
.group-management-container h3 { font-size: 1.75rem; margin-bottom: var(--space-lg); text-align: center; }
.member-list { display: flex; flex-direction: column; gap: 0.75rem; margin-bottom: var(--space-xl); }
.member-item {
    display: flex; justify-content: space-between; align-items: center; padding: var(--space-sm) var(--space-md);
    background-color: color-mix(in srgb, var(--c-surface) 50%, transparent);
    backdrop-filter: blur(5px);
    border-radius: var(--radius-md); 
    border: var(--border-width) solid color-mix(in srgb, var(--c-border) 40%, transparent);
    box-shadow: inset 0 1px 1px color-mix(in srgb, var(--c-surface) 50%, transparent);
    transition: all 0.3s ease, opacity 0.5s ease; 
    opacity: 0; transform: translateY(10px);
    animation: fadeIn 0.5s ease forwards;
}
.member-item:hover { 
    transform: translateY(-4px); 
    box-shadow: 0 8px 25px -5px var(--c-shadow-color); 
    border-color: var(--c-accent);
}
.member-item.removing { opacity: 0; transform: translateX(-20px); }
.member-actions { display: flex; align-items: center; gap: var(--space-md); }
.member-role { font-size: 0.8rem; font-weight: var(--fw-semibold); padding: 0.3rem 0.6rem; border-radius: var(--radius-sm); background-color: color-mix(in srgb, var(--c-bg) 50%, var(--c-surface)); color: var(--c-text-secondary); }
.member-role.admin { background-color: var(--c-accent); color: var(--c-light-text-on-accent); }
.remove-member-btn { 
    color: var(--c-text-secondary);
    border-radius: 50%;
    width: 32px;
    height: 32px;
    transition: all var(--transition-fast);
}
.remove-member-btn:hover { 
    color: var(--c-error); 
    background-color: color-mix(in srgb, var(--c-error) 15%, transparent); 
    transform: scale(1.1);
}

.add-member-form { display: flex; gap: var(--space-md); }
.add-member-form input { 
    flex-grow: 1; 
    border-radius: var(--radius-md); 
    padding: 0.85rem 1.1rem; 
    background-color: color-mix(in srgb, var(--c-surface) 50%, transparent);
    border: 1px solid color-mix(in srgb, var(--c-border) 40%, transparent);
}
.add-member-form input:focus {
    border-color: var(--c-accent);
    box-shadow: 0 0 0 4px color-mix(in srgb, var(--c-accent) 20%, transparent);
}
.add-member-form input.error { animation: shake 0.5s ease-in-out; border-color: var(--c-error); }
.add-member-form button {
    font-weight: var(--fw-semibold); 
    font-size: 1rem; 
    padding: 0.75rem var(--space-lg); 
    border: none;
    border-radius: var(--radius-md); 
    background: linear-gradient(45deg, var(--c-accent), color-mix(in srgb, var(--c-accent) 80%, black 10%));
    color: var(--c-light-text-on-accent);
    cursor: pointer; 
    transition: all var(--transition-fast);
    box-shadow: 0 4px 15px -5px color-mix(in srgb, var(--c-accent) 50%, transparent);
}
.add-member-form button:hover { 
    opacity: 1; 
    transform: translateY(-3px); 
    box-shadow: 0 6px 20px -5px color-mix(in srgb, var(--c-accent) 50%, transparent);
}
.add-member-form button:active { transform: translateY(0); opacity: 0.9; }
.add-member-form button:disabled { opacity: 0.6; cursor: wait; background: var(--c-border); box-shadow: none; transform: none; }
/* --- End Modernized Section --- */

.account-actions { display: flex; justify-content: center; }
.logout-button {
    color: var(--c-text-secondary); font-size: 1rem; cursor: pointer; padding: var(--space-xs) var(--space-md);
    border-radius: var(--radius-md); transition: all var(--transition-fast);
    background: none; border: none; font-weight: var(--fw-regular);
}
.logout-button:hover { color: var(--c-error); background-color: color-mix(in srgb, var(--c-error) 10%, transparent); }

/* --- Toasts --- */
#toast-container {
    position: fixed;
    bottom: calc(70px + env(safe-area-inset-bottom));
    right: 20px;
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.toast {
    padding: 14px 22px; border-radius: var(--radius-md); font-weight: var(--fw-semibold);
    color: var(--c-light-text-on-accent); box-shadow: 0 5px 25px rgba(0,0,0,0.15);
    opacity: 0; transform: translateX(calc(100% + 20px));
    transition: all 0.6s cubic-bezier(0.68, -0.6, 0.27, 1.55);
}
.toast.show { opacity: 1; transform: translateX(0); }
.toast.toast-success { background-color: var(--c-success); }
.toast.toast-error { background-color: var(--c-error); }
.toast.toast-info { background-color: var(--c-info); }

/* --- Practice Page --- */
.practice-container {
    display: flex; flex-direction: column; align-items: center; justify-content: center;
    gap: var(--space-xxl); width: 100%; max-width: 500px; flex-grow: 1; padding: var(--space-xl); margin: 0 auto;
}
.flashcard-container { height: 280px; }
.flashcard-term { font-size: 2.25rem; font-weight: var(--fw-bold); min-height: 44px; }
.flashcard-definition { font-size: 1.25rem; min-height: 30px; }
.practice-controls { display: flex; gap: var(--space-sm); align-items: center; justify-content: center; flex-wrap: wrap; }
.practice-btn {
    font-size: 1rem; font-weight: var(--fw-semibold);
    padding: 0.75rem var(--space-lg); border-radius: var(--radius-full);
    border: var(--border-width) solid var(--c-border); background-color: var(--c-surface);
    color: var(--c-text-primary); cursor: pointer; transition: all var(--transition-fast);
}
.practice-btn:hover { transform: translateY(-3px); border-color: var(--c-accent); box-shadow: var(--shadow-sm); }
.practice-btn:active { transform: translateY(0); }
.practice-btn.shuffle { background-color: var(--c-accent); color: var(--c-light-text-on-accent); border-color: var(--c-accent); }
.practice-btn.known { background-color: var(--c-success); color: var(--c-light-text-on-accent); border-color: var(--c-success); }
.card-counter { color: var(--c-text-secondary); font-weight: var(--fw-semibold); }

/* --- Subscription Page --- */
.subscription-page-main { padding: 120px 0 60px 0; }
.subscription-container { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: var(--space-xxl); max-width: 1100px; margin: 0 auto 3rem; padding: 0 var(--space-xl); }
.tier-box {
    background-color: var(--c-surface); border: var(--border-width) solid var(--c-border);
    border-radius: var(--radius-lg); padding: var(--space-xxl) var(--space-xl); display: flex;
    flex-direction: column; transition: all var(--transition-medium);
    box-shadow: 0 4px 20px var(--c-shadow-color); position: relative;
}
.tier-box:hover { transform: translateY(-8px); box-shadow: var(--shadow-md); }
.tier-box.recommended { border-color: var(--c-accent); }
.tier-badge {
    position: absolute; top: var(--space-lg); right: var(--space-lg);
    background-color: var(--c-accent); color: var(--c-light-text-on-accent);
    padding: 0.3rem var(--space-xs); font-size: 0.8rem; font-weight: var(--fw-bold);
    border-radius: var(--radius-full);
}
.tier-header { text-align: center; margin-bottom: var(--space-lg); }
.tier-name { font-size: 1.75rem; }
.tier-price { font-size: 1.25rem; color: var(--c-text-secondary); }
.tier-price span { font-size: 3.5rem; color: var(--c-text-primary); }
.tier-description { text-align: center; color: var(--c-text-secondary); margin-bottom: var(--space-xl); min-height: 40px; font-size: 0.9rem; }
.tier-perks { list-style: none; margin-bottom: var(--space-xl); flex-grow: 1; padding: 0; }
.tier-perks li {
    padding: 0.85rem 0; border-bottom: var(--border-width) solid var(--c-border);
    color: var(--c-text-primary); font-size: 0.95rem;
    opacity: 0; transform: translateY(10px); animation: fadeIn 0.5s ease forwards;
}
.tier-perks li::before { content: '✓'; color: var(--c-accent); margin-right: var(--space-sm); font-weight: var(--fw-bold); }
.tier-button {
    width: 100%; padding: 1.1rem; font-size: 1rem; font-weight: var(--fw-semibold);
    color: var(--c-light-text-on-accent); background-color: var(--c-text-primary);
    border: none; border-radius: var(--radius-full); cursor: pointer;
    transition: all var(--transition-fast); margin-top: auto;
}
.tier-button:hover { opacity: 0.85; transform: translateY(-3px); box-shadow: 0 6px 20px color-mix(in srgb, var(--c-text-primary) 30%, transparent); }
.tier-button:active { transform: translateY(0); opacity: 1; }
.tier-button:disabled { background-color: var(--c-border); color: var(--c-text-secondary); cursor: not-allowed; }
.tier-button:disabled:hover { transform: none; box-shadow: none; opacity: 1; }
.tier-box.recommended .tier-button { background-color: var(--c-accent); }
.tier-box.recommended .tier-button:hover { box-shadow: 0 6px 20px color-mix(in srgb, var(--c-accent) 30%, transparent); }


/* --- [NEW] Site Footer with Depth --- */
.site-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    padding: var(--space-sm) var(--space-md);
    text-align: center;
    font-size: 0.85rem;
    color: var(--c-text-secondary);
    z-index: 50;
    transition: background-color var(--transition-medium);
    /* Depth styles */
    box-shadow: 0 -4px 30px rgba(0,0,0,0.1);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    background-color: color-mix(in srgb, var(--c-surface) 80%, transparent);
    border-top: 1px solid color-mix(in srgb, var(--c-border) 50%, transparent);
}

/* ==========================================================================
   5. ANIMATIONS & MEDIA QUERIES
   ========================================================================== */
@keyframes fadeIn { from { opacity: 0; transform: translateY(15px); } to { opacity: 1; transform: translateY(0); } }
@keyframes popIn { from { opacity: 0; transform: scale(0.8); } to { opacity: 1; transform: scale(1); } }
@keyframes shake { 0%, 100% { transform: translateX(0); } 10%, 30%, 50%, 70%, 90% { transform: translateX(-5px); } 20%, 40%, 60%, 80% { transform: translateX(5px); } }
@keyframes cardReveal {
    0% {
        opacity: 0;
        transform: translateY(24px) translateX(-6px);
        clip-path: inset(0 0 100% 0 round 14px);
    }
    58% {
        opacity: 1;
        transform: translateY(0) translateX(0);
        clip-path: inset(0 0 0 0 round 14px);
    }
    100% {
        opacity: 1;
        transform: translateY(0) translateX(0);
        clip-path: inset(0 0 0 0 round 14px);
    }
}
@keyframes cardSweep {
    from { transform: translateX(-120%); }
    to { transform: translateX(120%); }
}

/* --- Staggered Animations --- */
.tier-perks li:nth-child(1) { animation-delay: 0.1s; }
.tier-perks li:nth-child(2) { animation-delay: 0.2s; }
.tier-perks li:nth-child(3) { animation-delay: 0.3s; }
.tier-perks li:nth-child(4) { animation-delay: 0.4s; }
.tier-perks li:nth-child(5) { animation-delay: 0.5s; }

.member-item:nth-child(1) { animation-delay: 0.05s; }
.member-item:nth-child(2) { animation-delay: 0.1s; }
.member-item:nth-child(3) { animation-delay: 0.15s; }
.member-item:nth-child(4) { animation-delay: 0.2s; }
.member-item:nth-child(5) { animation-delay: 0.25s; }


/* --- Media Queries --- */
@media (max-width: 768px) {
    header {
        top: 12px;
        left: 12px;
        right: 12px;
    }
    .page-main-content { padding-top: 80px; }
    .add-member-form { flex-direction: column; }
    .page-title { font-size: 2rem; }
    .account-profile { flex-direction: column; text-align: center; }
    .recognizer-controls { grid-template-columns: 1fr; }
    .calibration-controls { flex-direction: column; }
    .recognizer-btn { width: 100%; text-align: center; }
    .calibration-select { width: 100%; }
    .search-demo-results {
        grid-template-columns: 1fr;
    }
    #home-page.results-visible .home-content {
        transform: translateY(-28px);
    }
    .site-footer {
        font-size: 0.8rem;
    }
    #toast-container {
        left: 12px;
        right: 12px;
        bottom: calc(72px + env(safe-area-inset-bottom));
    }
    .toast {
        width: 100%;
        transform: translateY(18px);
    }
    .toast.show {
        transform: translateY(0);
    }
}
@media (max-width: 480px) {
    header {
        flex-direction: column;
        align-items: flex-end;
        gap: 10px;
        height: auto;
    }
    .header-nav { order: 2; }
    #theme-manager { order: 1; }
    #theme-manager.themes-visible .theme-switcher {
        max-width: calc(100vw - 80px); /* Adjust to fit screen */
        flex-wrap: wrap;
        justify-content: flex-end;
    }
    .sotd-wrapper {
        margin-bottom: var(--space-lg);
    }
    .search-form input {
        padding-right: 8.8rem;
    }
    .search-clear-btn {
        right: 5.15rem;
    }
    .search-submit-btn {
        padding: 0.5rem 0.8rem;
        font-size: 0.8rem;
    }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation: none !important;
        transition: none !important;
        scroll-behavior: auto !important;
    }
}