:root {
    /* Colors */
    --primary: #4da3ff;
    --secondary: #0066cc;
    --bg-main: #0f172a;
    --bg-card: #1e293b;
    --bg-footer: #0f172a;
    --text-main: #ffffff;
    --text-muted: #94a3b8;
    --border-soft: rgba(255, 255, 255, 0.1);
    
    /* Variables used in your menu/cards */
    --color-black-300: #1e293b;
    --color-white-100: #f8fafc;
    --color-blue-500: #3b82f6;
    --color-blue-600: #2563eb;
    --shadow-medium: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-soft: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 16px;
}

/* Light theme overrides: apply when body has .light OR when JS sets data-theme="light" on the documentElement */
body.light, [data-theme="light"] {
    --bg-main: #f8fafc; /* page background */
    --bg-card: #ffffff; /* card background */
    --bg-footer: #f1f5f9;
    --text-main: #0f172a; /* primary text */
    --text-muted: #475569; /* muted text */
    --border-soft: rgba(15, 23, 42, 0.06);
    --primary: #2563eb; /* primary tint for light mode */
    --secondary: #3b82f6;
    --shadow-soft: 0 10px 20px rgba(16,24,40,0.06);
    /* Ensure formerly-dark helper colors update in light mode */
    --color-black-300: #f8fafc; /* menus, overlays */
    --color-white-100: #0f172a; /* used for link/text on dark backgrounds; invert in light mode */
}

/* Smooth color transitions when toggling theme */
body {
    transition: background-color 0.35s ease, color 0.35s ease;
}

/* Add a basic body reset so flexbox works */
body {
    margin: 0;
    font-family: sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Make sizing easier to reason about: include padding/border in element width/height */
*, *::before, *::after {
    box-sizing: border-box;
}


/* Small element resets (avoid constraining layout width) */
input, button { font-family: inherit; }
div.error { margin-top:10px; color:red; }


.menu { position: fixed; top: -100%; left: 0; width: 100%; height: auto; overflow: hidden; padding-block: 4rem; background-color: var(--color-black-300); box-shadow: var(--shadow-medium); transition: all 0.4s ease-in-out; z-index: 1600; }
.menu.is-active { top: 0; width: 100%; height: auto; }
.menu-inner { display: flex; flex-direction: column; justify-content: center; align-items: center; row-gap: 1.25rem; }
.menu-link { font-family: inherit; font-size: 1rem; font-weight: 500; line-height: 1.5; color: var(--color-white-100); text-transform: uppercase; transition: all 0.3s ease; }
.menu-link:focus { outline: 2px solid var(--color-blue-500); outline-offset: 2px; }
.menu-block { display: inline-block; font-family: inherit; font-size: 0.875rem; font-weight: 500; line-height: 1.25; user-select: none; white-space: nowrap; text-align: center; margin-left: auto; padding: 0.65rem 1.5rem; border-radius: 3rem; text-transform: capitalize; color: var(--color-white); background-color: var(--color-blue-600); box-shadow: var(--shadow-medium); transition: all 0.3s ease-in-out; }

@media only screen and (min-width: 48rem) {
   .menu { position: relative; top: 0; width: auto; height: auto; padding: 0rem; margin-left: auto; background: none; box-shadow: none; }
   .menu-inner { display: flex; flex-direction: row; column-gap: 2rem; margin: 0 auto; }
   .menu-link { text-transform: capitalize; }
   .menu-block { margin-left: 2rem; }
}


.logo {
    font-size: 1.3rem;
    font-weight: 700;
    letter-spacing: 0.5px;
    color: var(--primary);
}

/* =========================
   ICON THEME TOGGLE
========================= */
.theme-toggle {
    position: fixed;
    top: 18px;
    right: 20px;
    z-index: 20;
}

.theme-toggle button {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: 1px solid var(--border-soft);
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: #fff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-soft);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.theme-toggle button:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 30px rgba(77, 163, 255, 0.45);
}

.theme-toggle i {
    font-size: 1.2rem;
    transition: transform 0.35s ease;
}

body.light .theme-toggle button {
    background: linear-gradient(135deg, #fbbf24, #f59e0b);
}

body.light .theme-toggle i {
    transform: rotate(180deg);
}

/* =========================
   ERROR BAR (slide-down)
========================= */
.error-bar {
    position: fixed;
    top: -60px;
    left: 50%;
    transform: translateX(-50%);
    width: 360px;
    max-width: calc(100% - 40px);
    height: 44px;
    background-color: #e74c3c; /* error red */
    color: #fff;
    display: flex;
    align-items: center;
    padding: 0 14px;
    border-radius: 0 0 8px 8px;
    box-shadow: 0 6px 20px rgba(0,0,0,0.25);
    overflow: hidden;
    z-index: 1000;
}

.error-bar i { margin-right: 10px; font-size: 18px; }
.error-text { flex: 1; font-size: 14px; font-weight: 600; }
.error-progress { position: absolute; bottom: 0; left: 0; height: 4px; background: rgba(255,255,255,0.85); width: 100%; }

.slide-down { animation: slideDown 0.28s forwards; }
@keyframes slideDown { 0% { top: -60px } 100% { top: 20px } }

/* shrink animation applied dynamically via JS to control duration */
@keyframes shrink { 0% { width: 100% } 100% { width: 0% } }

/* SUCCESS BAR */
.success-bar {
    position: fixed;
    top: -60px;
    left: 50%;
    transform: translateX(-50%);
    width: 360px;
    max-width: calc(100% - 40px);
    height: 44px;
    background-color: #28a745; /* success green */
    color: #fff;
    display: flex;
    align-items: center;
    padding: 0 14px;
    border-radius: 0 0 8px 8px;
    box-shadow: 0 6px 20px rgba(0,0,0,0.16);
    overflow: hidden;
    z-index: 1000;
}

.success-bar i { margin-right: 10px; font-size: 18px; }
.success-text { flex: 1; font-size: 14px; font-weight: 600; }
.success-progress { position: absolute; bottom: 0; left: 0; height: 4px; background: rgba(255,255,255,0.85); width: 100%; }

.slide-down-success { animation: slideDown 0.28s forwards; }
.slide-up-success { animation: slideUp 0.28s forwards; }
/* =========================
   LOGIN LAYOUT
========================= */
.login-container {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 30px 16px;
}

/* =========================
   LOGIN CARD
========================= */
.login-card {
    width: 100%;
    max-width: 420px;
    background: linear-gradient(
        180deg,
        rgba(255, 255, 255, 0.04),
        transparent
    ),
    var(--bg-card);
    border: 1px solid var(--border-soft);
    border-radius: var(--radius);
    padding: 36px 32px;
    box-shadow: var(--shadow-soft);
    animation: fadeUp 0.8s ease;
}

.login-card h2 {
    font-size: 1.9rem;
    margin-bottom: 8px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.login-card p {
    font-size: 0.95rem;
    color: var(--text-muted);
    margin-bottom: 26px;
}

/* =========================
   INPUTS
========================= */
.input-group {
    margin-bottom: 18px;
}

.input-group input {
    width: 100%;
    max-width: 100%; /* never exceed container */
    padding: 14px 16px;
    border-radius: 10px;
    border: 1px solid var(--border-soft);
    background: transparent;
    color: var(--text-main);
    outline: none;
    transition: all 0.3s ease;
    box-sizing: border-box; /* ensure padding doesn't increase element width */
}

/* Invalid input highlight used by client-side validation */
.input-group input.input-error {
    border-color: #e74c3c;
    box-shadow: 0 0 0 4px rgba(231,76,60,0.08);
}

.error-message {
    color: #e74c3c;
    font-size: 0.85rem;
    margin-top: 6px;
    display: block;
}

.input-group input::placeholder {
    color: var(--text-muted);
}

.input-group input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(77, 163, 255, 0.2);
}

/* =========================
   LOGIN BUTTON
========================= */
.login-btn {
    width: 100%;
    padding: 14px;
    border-radius: 12px;
    border: none;
    font-weight: 600;
    font-size: 1rem;
    color: #fff;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    cursor: pointer;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.login-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 30px rgba(77, 163, 255, 0.4);
}

.login-btn:active {
    transform: scale(0.98);
}

/* =========================
   LOGIN MESSAGE
========================= */
#loginMsg {
    margin-top: 16px;
    font-size: 0.9rem;
    text-align: center;
}

/* =========================
   FOOTER
========================= */
footer {
    background: var(--bg-footer);
    backdrop-filter: blur(14px);
    border-top: 1px solid var(--border-soft);
}

.footer-inner {
    max-width: 1100px;
    margin: auto;
    padding: 16px 20px;
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* =========================
   ANIMATIONS
========================= */
@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* =========================
   RESPONSIVE
========================= */
@media (max-width: 480px) {
    .login-card {
        padding: 28px 22px;
    }
}

.signin-btn {
    color: var(--primary);
    font-weight: 600;
    text-decoration: none;
}

/* =========================
   PAGE LOADER
   Simple full-screen loader shown while page loads.
========================= */
#pageLoader {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-main);
    z-index: 2000;
    opacity: 1;
    transition: opacity 0.45s ease;
}

.loader-logo {
    width: 220px; /* increased size */
    height: auto;
    display: block;
    filter: drop-shadow(0 10px 36px rgba(0,0,0,0.6));
    transform-origin: center;
    will-change: transform;
    backface-visibility: hidden;
    /* pop in/out effect */
    animation: loader-pop 1s ease-in-out infinite;
}

@keyframes loader-pop {
    0% {
        transform: scale(0.85);
        opacity: 0;
    }
    30% {
        transform: scale(1.08);
        opacity: 1;
    }
    60% {
        transform: scale(0.96);
        opacity: 0.95;
    }
    100% {
        transform: scale(0.85);
        opacity: 0;
    }
}

.header-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Site header/navbar for practice pages */
.header {
    width: 100%;
    background: linear-gradient(180deg, rgba(255,255,255,0.02), transparent);
    border-bottom: 1px solid var(--border-soft);
    backdrop-filter: blur(6px);
}

.navbar ul { display: flex; gap: 1rem; margin: 0; padding: 0; list-style: none; align-items:center; }
.navbar a { color: var(--text-muted); text-decoration: none; font-weight: 600; padding: 8px 10px; border-radius: 8px; transition: all 0.18s ease; }
.navbar a:hover { color: var(--text-main); background: rgba(255,255,255,0.03); }
.navbar a.active { color: var(--text-main); background: rgba(255,255,255,0.04); }

.page-content { max-width: 1100px; margin: 28px auto; padding: 0 20px 60px; }

/* Footer enhancements */
.footer-inner { max-width: 1100px; margin: auto; padding: 20px; }
.footer-grid { display: flex; gap: 1rem; align-items: center; justify-content: space-between; flex-wrap: wrap; }
.footer-brand { font-weight: 800; color: var(--primary); font-size: 1.05rem; }
.footer-links a { color: var(--text-muted); text-decoration: none; margin-right: 12px; font-weight: 600; }
.footer-links a:hover { color: var(--text-main); }
.footer-info { color: var(--text-muted); font-size: 0.95rem; }

@media (max-width: 680px) {
    .navbar ul { gap: 0.5rem; }
    .header-inner { padding: 12px 14px; }
    .page-content { margin: 18px auto; padding: 0 14px 60px; }
    .footer-grid { text-align: center; gap: 10px; }
}

/* Header Styles (theme-aware) */
.header {
    /* default header uses the card background so it's light in light mode */
    background: var(--bg-card, linear-gradient(135deg, #1f3a60, #233d64));
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.12);
}

/* Stronger styling for dark theme to preserve contrast and style */
[data-theme="dark"] .header, body:not(.light) .header {
    background: linear-gradient(135deg, #1f3a60, #233d64);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.7);
}

.welcome-message h1 {
    font-size: 30px;
    color: var(--primary);
    text-shadow: none;
}

.navbar ul { list-style: none; display: flex; gap: 20px; }
.navbar ul li { position: relative; }
.navbar ul li a { color: var(--text-muted); text-decoration: none; font-size: 18px; transition: color 0.3s; }
.navbar ul li a:hover { color: var(--primary); }

.navbar ul li a .logout-icon {
    font-size: 22px;
    padding-right: 10px;
}

/* General Styles (use CSS variables so theme toggles correctly) */
body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--bg-main);
    color: var(--text-main);
}

/* Headings */
h2 {
    text-align: center;
    color: var(--text-main);
    margin-top: 20px;
}

/* Setup Section Styles */
#setupSection {
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
    background: var(--bg-card);
    border-radius: 10px;
    box-shadow: var(--shadow-soft, 0 4px 10px rgba(0, 0, 0, 0.08));
}

.setup-item {
    margin-bottom: 15px;
}

label {
    font-size: 18px;
}

select, input {
    width: 100%;
    padding: 10px;
    margin-top: 5px;
    background-color: transparent;
    color: var(--text-main);
    border: 1px solid var(--border-soft);
    border-radius: 5px;
    font-size: 16px;
}

button {
    width: 100%;
    padding: 12px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--text-main-on-primary, #fff);
    border: none;
    border-radius: 5px;
    font-size: 18px;
    cursor: pointer;
    margin-top: 20px;
}

button:hover { opacity: 0.95; }

/* Exam Section */
#examSection {
    background-color: var(--bg-card);
    border-radius: 10px;
    padding: 20px;
    margin: 20px auto;
    max-width: 600px;
}

#timer { text-align: center; font-size: 28px; color: var(--text-main); }

/* Result Section */
#resultSection {
    padding: 20px;
    text-align: center;
    background-color: var(--bg-card);
    border-radius: 10px;
    max-width: 600px;
    margin: 20px auto;
}

/* Pop-up Modal */
.popup {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.popup-content {
    background-color: var(--bg-card);
    padding: 30px;
    border-radius: 10px;
    text-align: center;
    max-width: 400px;
    width: 100%;
    color: var(--text-main);
    border: 1px solid var(--border-soft);
}

.popup h3 { color: var(--primary); font-size: 24px; }
.popup p { font-size: 18px; color: var(--text-main); }
.popup button { padding: 12px; background: linear-gradient(135deg, var(--primary), var(--secondary)); color: var(--text-main-on-primary, #fff); font-size: 18px; border: none; border-radius: 5px; cursor: pointer; width: 100%; }
.popup button:hover { opacity: 0.95; }

/* Make popup overlay lighter in light mode */
body.light .popup, [data-theme="light"] .popup { background-color: rgba(255,255,255,0.6); }