/* ═══════════════════════════════════════════════════════
   Anti-Cheating Exam — GLASSMORPHISM Edition
   Frosted glass UI · Premium dark gradient · Glow effects
   ═══════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap');

/* ── 1. CSS Variables ─────────────────────────────── */
:root {
    /* Background */
    --bg:           #060B18;
    --bg-grad:      linear-gradient(135deg, #060B18 0%, #0D1630 50%, #060B18 100%);

    /* Glass layers */
    --glass-1:      rgba(255, 255, 255, 0.05);
    --glass-2:      rgba(255, 255, 255, 0.08);
    --glass-3:      rgba(255, 255, 255, 0.12);
    --glass-border: rgba(255, 255, 255, 0.12);
    --glass-border-bright: rgba(255, 255, 255, 0.22);

    /* Colours */
    --accent:       #4D9FFF;
    --accent-dark:  #2478E4;
    --accent-glow:  rgba(77, 159, 255, 0.45);
    --green:        #34D399;
    --green-glow:   rgba(52, 211, 153, 0.35);
    --red:          #F87171;
    --orange:       #FBBF24;
    --purple:       #A78BFA;
    --pink:         #F472B6;

    /* Text */
    --text-1:       #F0F6FF;
    --text-2:       rgba(240, 246, 255, 0.6);
    --text-3:       rgba(240, 246, 255, 0.3);
    --white:        #FFFFFF;

    /* Misc */
    --radius:       20px;
    --radius-sm:    14px;
    --radius-xs:    10px;
    --blur:         blur(20px);
    --blur-sm:      blur(12px);
    --shadow:       0 8px 40px rgba(0, 0, 0, 0.5);
    --shadow-glow:  0 8px 40px rgba(77, 159, 255, 0.2);
    --font:         'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --transition:   0.28s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ── 2. Reset & Base ──────────────────────────────── */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-tap-highlight-color: transparent;
}

html {
    height: 100%;
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text-1);
    min-height: 100vh;
    min-height: 100dvh;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    position: relative;
}

/* ── 3. Global Gradient Background ───────────────── */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background: var(--bg-grad);
    z-index: -3;
    pointer-events: none;
}

/* Floating colour orbs (rendered once on body) */
body::after {
    content: '';
    position: fixed;
    inset: 0;
    background:
        radial-gradient(ellipse 60% 50% at 15% 15%, rgba(77, 159, 255, 0.18) 0%, transparent 70%),
        radial-gradient(ellipse 50% 40% at 85% 10%, rgba(167, 139, 250, 0.14) 0%, transparent 65%),
        radial-gradient(ellipse 55% 45% at 80% 85%, rgba(52, 211, 153, 0.10) 0%, transparent 65%),
        radial-gradient(ellipse 45% 40% at 10% 80%, rgba(244, 114, 182, 0.10) 0%, transparent 65%);
    z-index: -2;
    pointer-events: none;
    animation: orb-drift 18s ease-in-out infinite alternate;
}

@keyframes orb-drift {
    0%   { opacity: 1; transform: scale(1)   translate(0,    0); }
    50%  { opacity: 0.8; transform: scale(1.05) translate(8px, -12px); }
    100% { opacity: 1; transform: scale(0.97) translate(-6px,  8px); }
}

/* ── 4. Typography ────────────────────────────────── */
h1 { font-size: clamp(1.5rem, 5.5vw, 2.2rem); font-weight: 900; line-height: 1.15; letter-spacing: -0.03em; }
h2 { font-size: clamp(1.1rem, 4.5vw, 1.5rem); font-weight: 700; }
h3 { font-size: 1.05rem; font-weight: 600; }
p  { line-height: 1.6; color: var(--text-2); }

/* ── 5. Page Layout ───────────────────────────────── */
.page {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    min-height: 100dvh;
    padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
}

.container {
    width: 100%;
    max-width: 1450px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ── 6. Glass Card ────────────────────────────────── */
.card {
    background: var(--glass-1);
    backdrop-filter: var(--blur);
    -webkit-backdrop-filter: var(--blur);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow), inset 0 1px 0 rgba(255,255,255,0.08);
    position: relative;
    overflow: hidden;
}

/* Top-edge shimmer line on cards */
.card::before {
    content: '';
    position: absolute;
    top: 0; left: 10%; right: 10%;
    height: 1px;
    background: linear-gradient(to right, transparent, rgba(255,255,255,0.3), transparent);
    border-radius: 0 0 2px 2px;
}

/* ── 7. Buttons ───────────────────────────────────── */
.btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
    padding: 16px 24px;
    border: none;
    border-radius: var(--radius-sm);
    font-family: var(--font);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    -webkit-user-select: none;
    user-select: none;
    touch-action: manipulation;
    position: relative;
    overflow: hidden;
}

.btn::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(180deg, rgba(255,255,255,0.08) 0%, transparent 100%);
    border-radius: inherit;
    pointer-events: none;
}

.btn:active { transform: scale(0.97); }

/* Primary — glowing blue */
.btn-primary {
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent-dark) 100%);
    color: var(--white);
    box-shadow: 0 6px 30px var(--accent-glow), inset 0 1px 0 rgba(255,255,255,0.25);
    border: 1px solid rgba(77, 159, 255, 0.4);
}
.btn-primary:hover {
    box-shadow: 0 10px 40px var(--accent-glow), inset 0 1px 0 rgba(255,255,255,0.3);
    transform: translateY(-2px);
    filter: brightness(1.08);
}

/* Outline — glass style */
.btn-outline {
    background: var(--glass-2);
    backdrop-filter: var(--blur-sm);
    -webkit-backdrop-filter: var(--blur-sm);
    color: var(--accent);
    border: 1.5px solid rgba(77, 159, 255, 0.35);
}
.btn-outline:hover {
    background: var(--glass-3);
    border-color: rgba(77, 159, 255, 0.6);
    transform: translateY(-2px);
}

/* Ghost */
.btn-ghost {
    background: var(--glass-1);
    color: var(--text-2);
    border: 1px solid var(--glass-border);
}
.btn-ghost:hover {
    background: var(--glass-2);
    color: var(--text-1);
}

/* Danger */
.btn-danger {
    background: linear-gradient(135deg, #F87171 0%, #DC2626 100%);
    color: var(--white);
    box-shadow: 0 6px 24px rgba(248,113,113,0.35);
    border: 1px solid rgba(248,113,113,0.4);
}

/* Green */
.btn-green {
    background: linear-gradient(135deg, var(--green) 0%, #059669 100%);
    color: #fff;
    box-shadow: 0 6px 24px var(--green-glow);
    border: 1px solid rgba(52,211,153,0.4);
}

.btn-sm { padding: 10px 16px; font-size: 0.875rem; }

.btn-hero {
    padding: 20px 24px;
    font-size: 1.05rem;
    border-radius: var(--radius);
}

.btn:disabled { opacity: 0.4; cursor: not-allowed; transform: none !important; }

/* ── 8. Form Elements ─────────────────────────────── */
.form-group { margin-bottom: 16px; }

.form-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-2);
    margin-bottom: 6px;
    text-transform: uppercase;
    letter-spacing: 0.07em;
}

.form-input {
    width: 100%;
    padding: 14px 16px;
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: var(--blur-sm);
    -webkit-backdrop-filter: var(--blur-sm);
    border: 1.5px solid var(--glass-border);
    border-radius: var(--radius-sm);
    color: var(--text-1);
    font-family: var(--font);
    font-size: 0.95rem;
    transition: border-color var(--transition), box-shadow var(--transition), background var(--transition);
    -webkit-appearance: none;
}

.form-input:focus {
    outline: none;
    border-color: rgba(77, 159, 255, 0.6);
    background: rgba(77, 159, 255, 0.06);
    box-shadow: 0 0 0 3px rgba(77, 159, 255, 0.12), 0 4px 20px rgba(77, 159, 255, 0.15);
}

.form-input::placeholder { color: var(--text-3); }
.form-input[type="number"]::-webkit-outer-spin-button,
.form-input[type="number"]::-webkit-inner-spin-button { -webkit-appearance: none; }

/* ── 9. Top Navigation Bar ────────────────────────── */
.top-bar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(6, 11, 24, 0.6);
    backdrop-filter: var(--blur);
    -webkit-backdrop-filter: var(--blur);
    border-bottom: 1px solid var(--glass-border);
    padding: 12px 20px;
    display: flex;
    align-items: center;
    gap: 12px;
    min-height: 56px;
}

.top-bar .back-btn {
    background: var(--glass-2);
    border: 1px solid var(--glass-border);
    color: var(--text-1);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 6px 12px;
    border-radius: 10px;
    line-height: 1;
    display: flex;
    align-items: center;
    flex-shrink: 0;
    text-decoration: none;
    transition: all var(--transition);
}
.top-bar .back-btn:hover {
    background: var(--glass-3);
    border-color: var(--glass-border-bright);
}

.top-bar .title {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--text-1);
    flex: 1;
}

/* ── 10. Badges ───────────────────────────────────── */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.72rem;
    font-weight: 600;
    backdrop-filter: var(--blur-sm);
}
.badge-blue   { background: rgba(77,159,255,0.12);  color: var(--accent);  border: 1px solid rgba(77,159,255,0.25); }
.badge-green  { background: rgba(52,211,153,0.12);  color: var(--green);   border: 1px solid rgba(52,211,153,0.25); }
.badge-red    { background: rgba(248,113,113,0.12); color: var(--red);     border: 1px solid rgba(248,113,113,0.25); }
.badge-orange { background: rgba(251,191,36,0.12);  color: var(--orange);  border: 1px solid rgba(251,191,36,0.25); }

/* ── 11. Dividers ─────────────────────────────────── */
.divider {
    height: 1px;
    background: linear-gradient(to right, transparent, var(--glass-border), transparent);
    margin: 20px 0;
}
.divider-accent {
    width: 48px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), var(--purple));
    border-radius: 2px;
    box-shadow: 0 0 10px var(--accent-glow);
}

/* ── 12. HOME PAGE ────────────────────────────────── */
.home-page {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    min-height: 100dvh;
    padding: 40px 24px;
    text-align: center;
}

/* Glass panel behind home content */
.home-glass-panel {
    background: var(--glass-1);
    backdrop-filter: var(--blur);
    -webkit-backdrop-filter: var(--blur);
    border: 1px solid var(--glass-border);
    border-radius: 32px;
    padding: 40px 28px;
    width: 100%;
    max-width: 380px;
    box-shadow:
        var(--shadow),
        inset 0 1px 0 rgba(255,255,255,0.1),
        0 0 60px rgba(77,159,255,0.08);
    position: relative;
    overflow: hidden;
}

/* Shimmer top line on panel */
.home-glass-panel::before {
    content: '';
    position: absolute;
    top: 0; left: 8%; right: 8%;
    height: 1px;
    background: linear-gradient(to right, transparent, rgba(255,255,255,0.35), transparent);
}

/* Subtle inner glow blob */
.home-glass-panel::after {
    content: '';
    position: absolute;
    top: -80px; left: 50%;
    transform: translateX(-50%);
    width: 260px;
    height: 200px;
    background: radial-gradient(circle, rgba(77,159,255,0.12) 0%, transparent 70%);
    pointer-events: none;
    z-index: 0;
}

.home-glass-panel > * { position: relative; z-index: 1; }

/* Logo */
.home-logo {
    width: 100px;
    height: 100px;
    margin: 0 auto 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

/* Rotating ring behind logo */
.home-logo::before {
    content: '';
    position: absolute;
    inset: -8px;
    border-radius: 50%;
    background: conic-gradient(from 0deg, var(--accent), var(--purple), var(--pink), var(--accent));
    animation: spin-ring 6s linear infinite;
    opacity: 0.7;
    filter: blur(2px);
}

/* White mask to create ring gap */
.home-logo::after {
    content: '';
    position: absolute;
    inset: -2px;
    border-radius: 50%;
    background: rgba(6,11,24,0.6);
    z-index: 0;
}

@keyframes spin-ring {
    to { transform: rotate(360deg); }
}

.home-logo img {
    width: 88px;
    height: 88px;
    object-fit: contain;
    border-radius: 50%;
    position: relative;
    z-index: 1;
    filter: drop-shadow(0 4px 16px rgba(77,159,255,0.4));
}

/* Title gradient */
.home-page h1 {
    background: linear-gradient(135deg, #fff 20%, rgba(180,210,255,0.9) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 6px;
    font-size: clamp(1.5rem, 7vw, 2rem);
    margin-top: 4px;
}

.home-tagline {
    font-size: 0.82rem;
    color: var(--text-2);
    margin-top: 4px;
    margin-bottom: 20px;
    letter-spacing: 0.04em;
}

.home-buttons {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
    width: 100%;
}

.home-buttons .btn {
    width: 384px; /* Exactly 4 inches */
    padding: 16px 20px;
    font-size: 0.95rem; /* Large, proportional font size */
    font-weight: 700;
    justify-content: center;
    text-align: center;
}

.btn-hero {
    border-radius: var(--radius);
}

/* Footer text inside panel */
.home-footer-text {
    margin-top: 24px;
    font-size: 0.68rem;
    color: var(--text-3);
    line-height: 1.6;
}

.home-footer-text .dev {
    color: var(--text-2);
    font-weight: 600;
    font-size: 0.7rem;
}

.home-footer-text .version {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    margin-top: 6px;
    padding: 3px 10px;
    background: var(--glass-1);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    backdrop-filter: var(--blur-sm);
    font-size: 0.63rem;
    color: var(--text-3);
}

/* ── 13. Teacher Page ─────────────────────────────── */
.teacher-page { padding-bottom: 40px; }

.qr-result-box { text-align: center; padding: 24px; }
.qr-result-box canvas,
.qr-result-box img {
    border-radius: 16px;
    border: 6px solid rgba(255,255,255,0.15);
    box-shadow: 0 8px 40px rgba(0,0,0,0.5), 0 0 0 1px rgba(255,255,255,0.08);
    max-width: 100%;
}

.qr-exam-info {
    margin-top: 16px;
    font-size: 0.88rem;
    color: var(--text-2);
    line-height: 1.8;
}
.qr-warning {
    margin-top: 10px;
    font-size: 0.75rem;
    color: var(--orange);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
}

/* ── 14. Scanner Page ─────────────────────────────── */
.scanner-page {
    position: fixed;
    inset: 0;
    background: #000;
    display: flex;
    flex-direction: column;
}
.scanner-header {
    position: absolute;
    top: 0; left: 0; right: 0;
    z-index: 10;
    background: linear-gradient(to bottom, rgba(0,0,0,0.85), transparent);
    backdrop-filter: var(--blur-sm);
    padding: 16px 20px 40px;
    display: flex;
    align-items: center;
    gap: 12px;
}
.scanner-header .back-btn {
    color: white;
    font-size: 1.4rem;
    background: rgba(255,255,255,0.1);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255,255,255,0.15);
    border-radius: 10px;
    padding: 6px 10px;
    cursor: pointer;
    text-decoration: none;
    transition: all var(--transition);
}
.scanner-header .back-btn:hover { background: rgba(255,255,255,0.18); }
.scanner-header .title { color: white; font-size: 1.05rem; font-weight: 700; }

#scanner-video { width: 100%; height: 100%; object-fit: cover; }

.scanner-overlay {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}
.scan-frame {
    width: min(75vw, 280px);
    height: min(75vw, 280px);
    position: relative;
}
.scan-frame::before, .scan-frame::after {
    content: '';
    position: absolute;
    width: 40px; height: 40px;
    border-color: var(--accent);
    border-style: solid;
    filter: drop-shadow(0 0 6px var(--accent));
}
.scan-frame::before { top: 0; left: 0; border-width: 4px 0 0 4px; border-radius: 8px 0 0 0; }
.scan-frame::after  { bottom: 0; right: 0; border-width: 0 4px 4px 0; border-radius: 0 0 8px 0; }
.scan-corner-tr, .scan-corner-bl {
    position: absolute;
    width: 40px; height: 40px;
    border-color: var(--accent);
    border-style: solid;
    filter: drop-shadow(0 0 6px var(--accent));
}
.scan-corner-tr { top: 0; right: 0; border-width: 4px 4px 0 0; border-radius: 0 8px 0 0; }
.scan-corner-bl { bottom: 0; left: 0; border-width: 0 0 4px 4px; border-radius: 0 0 0 8px; }
.scan-line {
    position: absolute;
    left: 8px; right: 8px;
    height: 2px;
    background: linear-gradient(to right, transparent, var(--accent), transparent);
    animation: scan-move 2s ease-in-out infinite;
    box-shadow: 0 0 12px var(--accent), 0 0 4px var(--accent);
}
@keyframes scan-move {
    0%   { top: 10%; }
    50%  { top: 88%; }
    100% { top: 10%; }
}
.scanner-footer {
    position: absolute;
    bottom: 0; left: 0; right: 0;
    background: linear-gradient(to top, rgba(0,0,0,0.9), transparent);
    backdrop-filter: blur(4px);
    padding: 32px 20px 40px;
    text-align: center;
}
.scanner-hint { color: rgba(255,255,255,0.7); font-size: 0.88rem; }
.scanner-status {
    margin-top: 12px;
    font-size: 0.85rem;
    color: var(--accent);
    min-height: 20px;
    text-shadow: 0 0 10px var(--accent-glow);
}

/* ── 15. Exam Page ────────────────────────────────── */
.exam-page {
    display: flex;
    flex-direction: column;
    height: 100vh;
    height: 100dvh;
    overflow: hidden;
}
.exam-timer {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--accent);
    white-space: nowrap;
    font-variant-numeric: tabular-nums;
    font-family: 'Courier New', monospace;
    transition: color 0.5s;
}
.exam-timer.warning { color: var(--red); animation: timer-blink 1s ease-in-out infinite; }
@keyframes timer-blink {
    0%, 100% { opacity: 1; }
    50%       { opacity: 0.4; }
}

/* ── 16. Modal / Dialog ───────────────────────────── */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    z-index: 1000;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition);
}
.modal-overlay.open { opacity: 1; pointer-events: auto; }
.modal {
    background: rgba(10, 18, 40, 0.8);
    backdrop-filter: var(--blur);
    -webkit-backdrop-filter: var(--blur);
    border: 1px solid var(--glass-border-bright);
    border-radius: var(--radius) var(--radius) 0 0;
    width: 100%;
    max-width: 480px;
    padding: 28px 24px calc(32px + env(safe-area-inset-bottom));
    transform: translateY(20px);
    transition: transform var(--transition);
    box-shadow: 0 -8px 40px rgba(0,0,0,0.4), inset 0 1px 0 rgba(255,255,255,0.12);
}
.modal-overlay.open .modal { transform: translateY(0); }
.modal-handle {
    width: 36px; height: 4px;
    background: rgba(255,255,255,0.2);
    border-radius: 2px;
    margin: 0 auto 20px;
}
.modal-title { font-size: 1.1rem; font-weight: 700; margin-bottom: 8px; }
.modal-desc  { font-size: 0.88rem; color: var(--text-2); margin-bottom: 20px; }
.modal-actions { display: flex; gap: 10px; margin-top: 16px; }

/* ── 17. Toast ────────────────────────────────────── */
.toast {
    position: fixed;
    bottom: calc(24px + env(safe-area-inset-bottom));
    left: 50%;
    transform: translateX(-50%) translateY(80px);
    background: rgba(10, 18, 40, 0.85);
    backdrop-filter: var(--blur);
    -webkit-backdrop-filter: var(--blur);
    border: 1px solid var(--glass-border-bright);
    border-radius: 14px;
    padding: 12px 22px;
    font-size: 0.88rem;
    font-weight: 500;
    color: var(--text-1);
    z-index: 2000;
    transition: transform 0.38s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.38s;
    opacity: 0;
    white-space: nowrap;
    box-shadow: 0 8px 40px rgba(0,0,0,0.5), inset 0 1px 0 rgba(255,255,255,0.1);
    pointer-events: none;
}
.toast.show    { transform: translateX(-50%) translateY(0); opacity: 1; }
.toast.error   { border-color: rgba(248,113,113,0.4);  color: var(--red);    box-shadow: 0 8px 40px rgba(248,113,113,0.15); }
.toast.success { border-color: rgba(52,211,153,0.4);   color: var(--green);  box-shadow: 0 8px 40px rgba(52,211,153,0.15); }
.toast.warning { border-color: rgba(251,191,36,0.4);   color: var(--orange); box-shadow: 0 8px 40px rgba(251,191,36,0.15); }

/* ── 18. Scrollbar ────────────────────────────────── */
::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.12); border-radius: 2px; }
::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.22); }

/* ── 19. Utility ──────────────────────────────────── */
.mt-4  { margin-top: 4px; }
.mt-8  { margin-top: 8px; }
.mt-12 { margin-top: 12px; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mt-32 { margin-top: 32px; }
.text-center { text-align: center; }
.text-sm  { font-size: 0.85rem; }
.text-xs  { font-size: 0.75rem; }
.text-muted  { color: var(--text-2); }
.text-accent { color: var(--accent); }
.text-red    { color: var(--red); }
.text-green  { color: var(--green); }
.fw-700 { font-weight: 700; }
.hidden { display: none !important; }

/* ── 20. PWA Install Banner ───────────────────────── */
.install-banner {
    position: fixed;
    top: calc(16px + env(safe-area-inset-top, 0px));
    right: 16px;
    width: 96px; /* 1 inch long size */
    height: 38px;
    background: rgba(6, 11, 24, 0.75);
    backdrop-filter: var(--blur);
    -webkit-backdrop-filter: var(--blur);
    border: 1px solid var(--glass-border-bright);
    border-radius: 19px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    z-index: 9999;
    transform: translateY(-80px);
    transition: transform var(--transition), opacity var(--transition), background var(--transition), border-color var(--transition);
    opacity: 0;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4), 0 0 10px rgba(77, 159, 255, 0.25);
    cursor: pointer;
    user-select: none;
}
.install-banner.show {
    transform: translateY(0);
    opacity: 1;
}
.install-banner:hover {
    background: rgba(6, 11, 24, 0.9);
    border-color: var(--accent);
    box-shadow: 0 6px 24px rgba(0, 0, 0, 0.5), 0 0 15px rgba(77, 159, 255, 0.4);
}
.install-banner .install-banner-icon {
    font-size: 1.1rem;
    line-height: 1;
    display: flex;
    align-items: center;
}
.install-banner .install-banner-text {
    font-size: 0.82rem;
    font-weight: 700;
    color: #ffffff;
    font-family: var(--font);
    letter-spacing: 0.02em;
}

/* ── 21. No-copy overlay ──────────────────────────── */
.no-copy-overlay {
    position: absolute;
    inset: 0;
    z-index: 10;
    pointer-events: none;
    -webkit-user-select: none;
    user-select: none;
}

/* ── 22. Spinner ──────────────────────────────────── */
.spinner {
    width: 36px; height: 36px;
    border: 3px solid rgba(255,255,255,0.1);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
    margin: 24px auto;
    box-shadow: 0 0 12px var(--accent-glow);
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── 23. Pulse glow animation (used in exam) ──────── */
@keyframes pulse-glow {
    0%, 100% { filter: drop-shadow(0 0 5px rgba(77,159,255,0.4)); transform: scale(1); }
    50%       { filter: drop-shadow(0 0 18px rgba(77,159,255,0.8)); transform: scale(1.05); }
}

/* ── 24. Responsive ───────────────────────────────── */
@media (min-width: 480px) {
    .container { padding: 0 32px; }
    .home-page  { padding: 60px 40px; }
}

@media (min-width: 768px) {
    body { display: flex; justify-content: center; }
    .page,
    .scanner-page,
    .exam-page { max-width: 1450px; width: 100%; }
    .modal-overlay { align-items: center; }
    .modal { border-radius: var(--radius); }
}