/* ============================================================
   EduVerse — Premium Education Platform Stylesheet
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&display=swap');

:root {
    --primary: #4f46e5;
    --primary-dark: #4338ca;
    --primary-light: #eef2ff;
    --secondary: #06b6d4;
    --accent: #f59e0b;
    --success: #16a34a;
    --danger: #dc2626;
    --dark: #0f172a;
    --slate: #1e293b;
    --gray: #64748b;
    --gray-light: #94a3b8;
    --light: #f8fafc;
    --border: #e2e8f0;
    --white: #ffffff;
    --gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #06b6d4 100%);
    --gradient-soft: linear-gradient(135deg, #eef2ff 0%, #f0f9ff 100%);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow: 0 4px 20px rgba(0,0,0,0.08);
    --shadow-lg: 0 20px 50px rgba(0,0,0,0.12);
    --radius: 14px;
    --radius-sm: 10px;
    --radius-lg: 20px;
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--dark);
    background: var(--light);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

/* ============ NAVBAR ============ */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    z-index: 1000;
    border-bottom: 1px solid rgba(226,232,240,0.8);
    transition: var(--transition);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
    gap: 2rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    letter-spacing: -0.02em;
}

.logo-badge {
    width: 32px;
    height: 32px;
    background: var(--gradient);
    border-radius: 9px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 0.25rem;
}

.nav-menu a {
    text-decoration: none;
    color: var(--gray);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.nav-menu a:hover { color: var(--primary); background: var(--primary-light); }
.nav-menu a.active { color: var(--primary); background: var(--primary-light); font-weight: 600; }

.nav-right { display: flex; align-items: center; gap: 0.75rem; }

.access-badge {
    display: none;
    align-items: center;
    gap: 0.35rem;
    background: #dcfce7;
    color: var(--success);
    font-size: 0.75rem;
    font-weight: 700;
    padding: 0.35rem 0.85rem;
    border-radius: 50px;
    white-space: nowrap;
}

.nav-login-btn {
    background: var(--gradient);
    color: var(--white);
    font-weight: 600;
    font-size: 0.9rem;
    padding: 0.55rem 1.2rem;
    border-radius: 8px;
    text-decoration: none;
    transition: var(--transition);
}

.nav-login-btn:hover { transform: translateY(-1px); box-shadow: 0 8px 20px rgba(79,70,229,0.3); }

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
    padding: 6px;
    z-index: 1001;
}

.hamburger span {
    width: 24px;
    height: 2.5px;
    background: var(--dark);
    border-radius: 3px;
    transition: var(--transition);
}

.hamburger.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: rotate(-45deg) translate(7px, -6px); }

/* ============ HERO ============ */
.hero {
    padding: 9rem 2rem 5rem;
    background: var(--gradient);
    position: relative;
    overflow: hidden;
    text-align: center;
    color: var(--white);
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 15% 20%, rgba(255,255,255,0.15) 0%, transparent 40%),
        radial-gradient(circle at 85% 80%, rgba(255,255,255,0.12) 0%, transparent 40%);
}

.hero-particles {
    position: absolute;
    inset: 0;
    background-image: radial-gradient(2px 2px at 20px 30px, rgba(255,255,255,0.3), transparent),
                      radial-gradient(2px 2px at 40px 70px, rgba(255,255,255,0.2), transparent),
                      radial-gradient(1px 1px at 90px 40px, rgba(255,255,255,0.3), transparent),
                      radial-gradient(1px 1px at 130px 80px, rgba(255,255,255,0.2), transparent),
                      radial-gradient(2px 2px at 160px 30px, rgba(255,255,255,0.3), transparent);
    background-size: 200px 100px;
    animation: drift 20s linear infinite;
    opacity: 0.5;
}

@keyframes drift { from { transform: translateY(0); } to { transform: translateY(100px); } }

.hero-content { position: relative; z-index: 2; max-width: 860px; margin: 0 auto; }

.hero-eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(255,255,255,0.15);
    border: 1px solid rgba(255,255,255,0.25);
    color: var(--white);
    font-size: 0.8rem;
    font-weight: 600;
    padding: 0.4rem 1rem;
    border-radius: 50px;
    margin-bottom: 1.5rem;
    backdrop-filter: blur(8px);
}

.hero h1 {
    font-size: clamp(2.5rem, 6vw, 4.2rem);
    font-weight: 900;
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: 1.25rem;
}

.hero h1 .highlight {
    background: linear-gradient(135deg, #fde047, #fb923c);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: rgba(255,255,255,0.9);
    max-width: 640px;
    margin: 0 auto 2.5rem;
    line-height: 1.6;
}

.search-box {
    display: flex;
    max-width: 560px;
    margin: 0 auto;
    background: var(--white);
    border-radius: 14px;
    overflow: hidden;
    box-shadow: 0 20px 50px rgba(0,0,0,0.2);
}

.search-box input {
    flex: 1;
    padding: 1.1rem 1.5rem;
    border: none;
    outline: none;
    font-size: 1rem;
    font-family: inherit;
    background: transparent;
}

.search-box button {
    padding: 0 1.6rem;
    border: none;
    background: var(--primary);
    color: var(--white);
    cursor: pointer;
    font-size: 1.1rem;
    transition: var(--transition);
}

.search-box button:hover { background: var(--primary-dark); }

.hero-stats {
    display: flex;
    justify-content: center;
    gap: clamp(2rem, 6vw, 5rem);
    margin-top: 3rem;
    flex-wrap: wrap;
}

.stat { text-align: center; }
.stat-number { display: block; font-size: 2.5rem; font-weight: 900; line-height: 1; }
.stat-label { font-size: 0.85rem; opacity: 0.85; font-weight: 500; }

/* ============ SECTION HEADERS ============ */
.section { padding: 5rem 2rem; }
.section-inner { max-width: 1400px; margin: 0 auto; }

.section-header { text-align: center; margin-bottom: 3rem; }
.section-eyebrow {
    display: inline-block;
    color: var(--primary);
    font-weight: 700;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: 0.75rem;
}
.section-title {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 0.75rem;
}
.section-subtitle { color: var(--gray); font-size: 1.05rem; max-width: 600px; margin: 0 auto; }

/* ============ FILTER ============ */
.filter-bar {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 2.5rem;
}

.filter-btn {
    padding: 0.6rem 1.3rem;
    border: 2px solid var(--border);
    background: var(--white);
    color: var(--gray);
    border-radius: 50px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.9rem;
    font-family: inherit;
    transition: var(--transition);
}

.filter-btn:hover { border-color: var(--primary); color: var(--primary); }
.filter-btn.active {
    background: var(--primary);
    border-color: var(--primary);
    color: var(--white);
    box-shadow: 0 6px 18px rgba(79,70,229,0.3);
}

/* ============ SUBJECT GRID ============ */
.subjects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.subject-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 1.75rem;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    text-decoration: none;
    display: flex;
    flex-direction: column;
}

.subject-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.35s;
}

.subject-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.subject-card:hover::before { transform: scaleX(1); }

.subject-card-header { display: flex; align-items: flex-start; gap: 1rem; margin-bottom: 1rem; }

.subject-icon {
    width: 52px;
    height: 52px;
    background: var(--gradient-soft);
    border: 1px solid var(--border);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.subject-icon svg { width: 26px; height: 26px; fill: var(--primary); }

.subject-card h3 {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--dark);
    line-height: 1.3;
    margin-bottom: 0.2rem;
}

.subject-card p {
    color: var(--gray);
    font-size: 0.875rem;
    line-height: 1.6;
    flex: 1;
    margin-bottom: 1rem;
}

.subject-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.5rem;
    margin-top: auto;
}

.subject-levels { display: flex; gap: 0.4rem; }

.level-badge {
    padding: 0.25rem 0.7rem;
    border-radius: 50px;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.level-badge.hs { background: var(--primary-light); color: var(--primary); }
.level-badge.uni { background: #fef3c7; color: #b45309; }

.card-arrow {
    color: var(--primary);
    font-weight: 700;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.25rem;
    font-size: 0.9rem;
}

.subject-card:hover .card-arrow { gap: 0.5rem; transform: translateX(2px); }

/* ============ FEATURES / WHY ============ */
.features-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
}

.feature-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem 1.5rem;
    text-align: center;
    transition: var(--transition);
}

.feature-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: transparent; }

.feature-icon {
    width: 56px;
    height: 56px;
    background: var(--gradient-soft);
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.25rem;
}

.feature-icon svg { width: 26px; height: 26px; fill: var(--primary); }

.feature-card h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 0.5rem; }
.feature-card p { color: var(--gray); font-size: 0.875rem; line-height: 1.6; }

/* ============ CATEGORIES ============ */
.category-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

.category-tile {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

.category-tile:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--primary); }

.category-tile .cat-icon {
    width: 48px; height: 48px;
    background: var(--gradient);
    border-radius: 12px;
    display: flex; align-items: center; justify-content: center;
    margin: 0 auto 1rem;
}
.category-tile .cat-icon svg { width: 22px; height: 22px; fill: var(--white); }

.category-tile h3 { font-size: 1rem; font-weight: 700; margin-bottom: 0.25rem; }
.category-tile p { color: var(--gray); font-size: 0.8rem; }

/* ============ ABOUT ============ */
.about-section { background: var(--white); }

.about-content {
    max-width: 1200px; margin: 0 auto;
    display: grid; grid-template-columns: 1.1fr 1fr;
    gap: 4rem; align-items: center;
}

.about-text h2 { font-size: 2rem; font-weight: 800; letter-spacing: -0.02em; margin-bottom: 1rem; }
.about-text p { color: var(--gray); font-size: 1.05rem; line-height: 1.8; margin-bottom: 1rem; }

.about-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.about-stat {
    background: var(--light);
    border-radius: var(--radius);
    padding: 1.25rem;
    text-align: center;
    border: 1px solid var(--border);
}
.about-stat .num { font-size: 1.75rem; font-weight: 900; color: var(--primary); display: block; }
.about-stat .lbl { font-size: 0.8rem; color: var(--gray); }

/* ============ CONTACT ============ */
.contact-content { display: grid; grid-template-columns: 1fr 1fr; gap: 4rem; max-width: 1200px; margin: 0 auto; }

.contact-form { display: flex; flex-direction: column; gap: 1rem; }
.form-group { display: flex; flex-direction: column; gap: 0.4rem; }
.form-group label { font-weight: 600; font-size: 0.9rem; }
.form-group input, .form-group textarea {
    padding: 0.85rem 1rem;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-family: inherit;
    outline: none;
    transition: var(--transition);
    background: var(--white);
}
.form-group input:focus, .form-group textarea:focus { border-color: var(--primary); box-shadow: 0 0 0 4px rgba(79,70,229,0.1); }

.submit-btn {
    padding: 0.95rem 2rem;
    background: var(--gradient);
    color: var(--white);
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-weight: 700;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition);
}
.submit-btn:hover { transform: translateY(-2px); box-shadow: 0 10px 30px rgba(79,70,229,0.3); }

.contact-info { display: flex; flex-direction: column; gap: 1.5rem; justify-content: center; }
.contact-item { display: flex; align-items: center; gap: 1rem; font-size: 1rem; }
.contact-item .ci-icon {
    width: 44px; height: 44px;
    background: var(--gradient-soft);
    border-radius: 12px;
    display: flex; align-items: center; justify-content: center;
    flex-shrink: 0;
}
.contact-item .ci-icon svg { width: 20px; height: 20px; fill: var(--primary); }

/* ============ CTA BANNER ============ */
.cta-banner {
    background: var(--gradient);
    border-radius: var(--radius-lg);
    padding: 3.5rem 2rem;
    text-align: center;
    color: var(--white);
    margin: 0 auto;
    max-width: 1200px;
    position: relative;
    overflow: hidden;
}
.cta-banner h2 { font-size: clamp(1.5rem, 3vw, 2.2rem); font-weight: 800; margin-bottom: 0.75rem; }
.cta-banner p { opacity: 0.9; margin-bottom: 1.5rem; font-size: 1.05rem; }
.cta-banner .btn-light {
    display: inline-block;
    background: var(--white);
    color: var(--primary);
    font-weight: 700;
    padding: 0.9rem 2rem;
    border-radius: 10px;
    text-decoration: none;
    transition: var(--transition);
}
.cta-banner .btn-light:hover { transform: translateY(-2px); box-shadow: 0 10px 25px rgba(0,0,0,0.2); }

/* ============ FOOTER ============ */
.footer { background: var(--dark); color: var(--white); padding: 4rem 2rem 1.5rem; }
.footer-content { max-width: 1200px; margin: 0 auto; display: grid; grid-template-columns: 1.5fr repeat(3, 1fr); gap: 3rem; }
.footer-section h4 { font-size: 1.05rem; font-weight: 700; margin-bottom: 1.25rem; }
.footer-section p { color: var(--gray-light); line-height: 1.7; font-size: 0.9rem; }
.footer-section ul { list-style: none; }
.footer-section ul li { margin-bottom: 0.6rem; }
.footer-section ul a { color: var(--gray-light); text-decoration: none; font-size: 0.9rem; transition: var(--transition); }
.footer-section ul a:hover { color: var(--white); }

.social-links { display: flex; gap: 0.75rem; }
.social-links a {
    width: 38px; height: 38px;
    background: rgba(255,255,255,0.08);
    border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    color: var(--white);
    transition: var(--transition);
}
.social-links a:hover { background: var(--primary); transform: translateY(-2px); }
.social-links svg { width: 17px; height: 17px; fill: var(--white); }

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    margin-top: 2.5rem;
    border-top: 1px solid rgba(255,255,255,0.08);
    color: var(--gray-light);
    font-size: 0.85rem;
}

/* ============ SUBJECT PAGE ============ */
.subject-hero {
    background: var(--gradient);
    color: var(--white);
    padding: 8rem 2rem 3rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}
.subject-hero::before {
    content: '';
    position: absolute; inset: 0;
    background: radial-gradient(circle at 50% 0%, rgba(255,255,255,0.15), transparent 60%);
}
.subject-hero-inner { position: relative; z-index: 2; max-width: 900px; margin: 0 auto; }

.breadcrumb { display: flex; align-items: center; justify-content: center; gap: 0.5rem; font-size: 0.85rem; opacity: 0.85; margin-bottom: 1.5rem; flex-wrap: wrap; }
.breadcrumb a { color: var(--white); text-decoration: none; opacity: 0.8; }
.breadcrumb a:hover { opacity: 1; text-decoration: underline; }
.breadcrumb span { opacity: 0.5; }

.subject-hero h1 { font-size: clamp(2rem, 5vw, 3rem); font-weight: 900; letter-spacing: -0.02em; margin-bottom: 1rem; display: flex; align-items: center; justify-content: center; gap: 1rem; flex-wrap: wrap; }
.subject-hero p { font-size: 1.15rem; opacity: 0.92; max-width: 640px; margin: 0 auto; }

.subject-layout {
    max-width: 1300px;
    margin: 0 auto;
    padding: 3rem 2rem;
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 3rem;
    align-items: start;
}

/* Sidebar */
.subject-sidebar { position: sticky; top: 90px; display: flex; flex-direction: column; gap: 1.5rem; }

.sidebar-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.25rem;
    box-shadow: var(--shadow-sm);
}

.sidebar-card h3 { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--gray); margin-bottom: 0.75rem; font-weight: 700; }

.progress-ring { text-align: center; padding: 0.5rem 0; }
.progress-ring .num { font-size: 1.75rem; font-weight: 900; color: var(--primary); display: block; }
.progress-ring .lbl { font-size: 0.8rem; color: var(--gray); }

.progress-bar { height: 8px; background: var(--border); border-radius: 50px; overflow: hidden; margin-top: 0.5rem; }
.progress-bar-fill { height: 100%; background: var(--gradient); border-radius: 50px; transition: width 0.5s; }

.sidebar-nav { list-style: none; display: flex; flex-direction: column; gap: 0.25rem; }
.sidebar-nav a {
    display: flex; align-items: center; gap: 0.6rem;
    padding: 0.55rem 0.75rem;
    border-radius: 8px;
    text-decoration: none;
    color: var(--gray);
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition);
}
.sidebar-nav a:hover, .sidebar-nav a.active { background: var(--primary-light); color: var(--primary); }

.sidebar-actions { display: flex; flex-direction: column; gap: 0.5rem; }
.sidebar-btn {
    padding: 0.65rem 0.9rem;
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition);
    border: 1px solid var(--border);
    background: var(--white);
    color: var(--gray);
    display: flex; align-items: center; gap: 0.5rem;
}
.sidebar-btn:hover { border-color: var(--primary); color: var(--primary); }
.sidebar-btn.primary { background: var(--gradient); color: var(--white); border: none; }
.sidebar-btn.primary:hover { transform: translateY(-1px); box-shadow: 0 6px 18px rgba(79,70,229,0.3); }

/* Content area */
.subject-content { display: flex; flex-direction: column; gap: 2.5rem; }

.content-tabs { display: flex; gap: 0.5rem; border-bottom: 2px solid var(--border); }
.content-tab {
    padding: 0.75rem 1.5rem;
    background: none;
    border: none;
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--gray);
    cursor: pointer;
    border-bottom: 3px solid transparent;
    margin-bottom: -2px;
    transition: var(--transition);
    display: flex; align-items: center; gap: 0.5rem;
}
.content-tab:hover { color: var(--primary); }
.content-tab.active { color: var(--primary); border-bottom-color: var(--primary); }
.content-tab .count { background: var(--border); color: var(--gray); font-size: 0.75rem; padding: 0.1rem 0.5rem; border-radius: 50px; font-weight: 700; }
.content-tab.active .count { background: var(--primary-light); color: var(--primary); }

.tab-panel { display: none; }
.tab-panel.active { display: block; animation: fadeIn 0.3s; }

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

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

.topic-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.25rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.topic-card::before {
    content: '';
    position: absolute;
    left: 0; top: 0; bottom: 0;
    width: 3px;
    background: var(--primary);
    transform: scaleY(0);
    transition: var(--transition);
}

.topic-card:hover { box-shadow: var(--shadow); transform: translateY(-3px); border-color: transparent; }
.topic-card:hover::before { transform: scaleY(1); }

.topic-card-header { display: flex; align-items: flex-start; gap: 0.75rem; margin-bottom: 0.5rem; }
.topic-card-header svg { width: 20px; height: 20px; fill: var(--primary); flex-shrink: 0; margin-top: 0.15rem; }
.topic-card h4 { font-size: 1rem; font-weight: 700; color: var(--dark); line-height: 1.4; }
.topic-card .topic-desc { color: var(--gray); font-size: 0.85rem; line-height: 1.6; margin: 0.4rem 0 0.6rem 1.75rem; }
.topic-card .topic-details { color: var(--gray-light); font-size: 0.78rem; line-height: 1.6; margin: 0 0 0 1.75rem; font-style: italic; }

.topic-check { position: absolute; top: 0.75rem; right: 0.75rem; width: 22px; height: 22px; cursor: pointer; accent-color: var(--primary); }

/* Content blocks inside subject pages */
.content-section { max-width: 100%; }
.content-section h2.section-heading {
    font-size: 1.4rem; color: var(--dark); margin: 2rem 0 1rem;
    padding-bottom: 0.5rem; border-bottom: 2px solid var(--border);
    display: flex; align-items: center; gap: 0.5rem;
}
.formula-box { background: var(--primary-light); border-left: 4px solid var(--primary); padding: 1rem 1.25rem; margin: 0.75rem 0; border-radius: 0 10px 10px 0; font-family: 'Courier New', monospace; font-size: 1rem; }
.code-box { background: var(--slate); color: #e2e8f0; padding: 1.25rem; margin: 0.75rem 0; border-radius: 10px; font-family: 'Courier New', monospace; font-size: 0.85rem; overflow-x: auto; white-space: pre; line-height: 1.6; }
.concept-card { background: var(--white); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.25rem; margin: 0.75rem 0; box-shadow: var(--shadow-sm); }
.concept-card h3 { font-size: 1.05rem; margin-bottom: 0.5rem; color: var(--dark); }
.concept-card p { color: var(--gray); font-size: 0.9rem; line-height: 1.7; }
.example-box { background: #f0fdf4; border-left: 4px solid var(--success); padding: 1rem 1.25rem; margin: 0.75rem 0; border-radius: 0 10px 10px 0; font-size: 0.9rem; }
.problem-box { background: #fffbeb; border-left: 4px solid var(--accent); padding: 1rem 1.25rem; margin: 0.75rem 0; border-radius: 0 10px 10px 0; font-size: 0.9rem; }

/* Related subjects */
.related-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 1rem; }
.related-card { background: var(--white); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.25rem; text-decoration: none; transition: var(--transition); }
.related-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: transparent; }
.related-card .rc-icon { width: 40px; height: 40px; background: var(--gradient-soft); border-radius: 10px; display: flex; align-items: center; justify-content: center; margin-bottom: 0.75rem; }
.related-card .rc-icon svg { width: 20px; height: 20px; fill: var(--primary); }
.related-card h4 { font-size: 0.95rem; font-weight: 700; }

/* Toast */
.toast {
    position: fixed; bottom: 2rem; left: 50%; transform: translateX(-50%) translateY(300%);
    background: var(--dark); color: var(--white);
    padding: 0.9rem 1.5rem; border-radius: 12px;
    box-shadow: var(--shadow-lg);
    font-weight: 600; font-size: 0.9rem; z-index: 2000;
    opacity: 0;
    transition: transform 0.3s, opacity 0.3s;
}
.toast:empty { display: none; }
.toast.show { transform: translateX(-50%) translateY(0); opacity: 1; }

/* ============ SCROLLBAR ============ */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--light); }
::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 5px; }
::-webkit-scrollbar-thumb:hover { background: #94a3b8; }

/* ============ RESPONSIVE ============ */
@media (max-width: 1024px) {
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .category-grid { grid-template-columns: repeat(2, 1fr); }
    .about-content, .contact-content { grid-template-columns: 1fr; }
    .footer-content { grid-template-columns: repeat(2, 1fr); }
    .subject-layout { grid-template-columns: 1fr; }
    .subject-sidebar { position: static; order: -1; }
    .subjects-grid { grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed; top: 70px; left: 0; width: 100%;
        background: var(--white); flex-direction: column; padding: 1.5rem;
        gap: 0.25rem; box-shadow: var(--shadow-lg);
        transform: translateY(-150%); transition: var(--transition);
    }
    .nav-menu.active { transform: translateY(0); }
    .hamburger { display: flex; }
    .hero { padding: 7rem 1.5rem 3rem; }
    .subjects-grid { grid-template-columns: 1fr; }
    .features-grid, .category-grid { grid-template-columns: 1fr; }
    .footer-content { grid-template-columns: 1fr; }
    .about-stats { grid-template-columns: 1fr; }
    .section { padding: 3.5rem 1.5rem; }
    .subject-layout { padding: 2rem 1.25rem; gap: 1.5rem; }
    .topic-grid { grid-template-columns: 1fr; }
    .content-tabs { overflow-x: auto; }
    .subject-hero { padding: 6.5rem 1.25rem 2rem; }
    .nav-login-btn { display: none; }
}

@media (max-width: 480px) {
    .hero h1 { font-size: 2rem; }
    .stat-number { font-size: 1.8rem; }
    .filter-btn { padding: 0.5rem 0.9rem; font-size: 0.8rem; }
    .subject-card { padding: 1.25rem; }
    .section-title { font-size: 1.5rem; }
    .nav-container { padding: 0 1rem; }
}

@media (max-width: 360px) {
    .hero h1 { font-size: 1.7rem; }
    .stat-number { font-size: 1.5rem; }
}

@media (max-height: 500px) and (orientation: landscape) {
    .hero { padding: 5rem 2rem 2rem; }
    .subject-hero { padding: 5rem 1.5rem 2rem; }
    .subject-layout { padding: 1.5rem 1rem; gap: 1rem; }
    .subject-sidebar { position: static; }
}

/* ============================================================
   COMPREHENSIVE RESPONSIVE ENHANCEMENTS
   Fits every resolution — from 320px phones to 4K monitors
   ============================================================ */

/* Prevent horizontal overflow everywhere */
html, body { overflow-x: hidden; max-width: 100%; }
img, video, svg, table, pre, code { max-width: 100%; height: auto; }
* { min-width: 0; }

/* Fix words spilling outside borders */
.topic-card, .topic-card h4, .topic-card .topic-desc, .topic-card .topic-details,
.subject-card h3, .subject-card p, .concept-card, .concept-card h3, .concept-card p,
.example-box, .problem-box, .formula-box, .code-box, .plan-card, .plan-card li,
.sidebar-card, .sidebar-nav a, .contact-item, .pay-detail, .footer-section p,
.footer-section a, .section-subtitle, .about-text p, .topic-card-header {
    overflow-wrap: break-word;
    word-wrap: break-word;
    word-break: break-word;
    hyphens: auto;
}

/* Allow long code/formula lines to wrap instead of overflowing */
.code-box, .formula-box {
    white-space: pre-wrap !important;
    word-break: break-word !important;
    overflow-wrap: anywhere;
    overflow-x: auto;
}

/* Headings can contain long words too */
.hero h1, .subject-hero h1, .section-title, .content-section h2, .content-section h3,
.topic-card-header h4, .sidebar-card h3, .dq-title, .dq-sub, .dq-note, .dq-question,
.dq-extra, .stat-number, .stat-label, .nav-menu a, .logo, .tab-panel p, .tab-panel li {
    overflow-wrap: anywhere;
    word-break: break-word;
}

/* Tables: let them scroll on narrow screens instead of spilling out */
table { max-width: 100%; }

/* Prevent grid/flex children from overflowing */
.subjects-grid, .topic-grid, .features-grid, .category-grid,
.plans-grid, .payment-methods, .about-stats, .related-grid { min-width: 0; }

/* Fluid base font size scales with viewport */
html { font-size: clamp(14px, 0.9vw + 0.4rem, 18px); }

/* ---- Large desktop / 1440px+ ---- */
@media (min-width: 1440px) {
    .subjects-grid { grid-template-columns: repeat(4, 1fr); }
    .topic-grid { grid-template-columns: repeat(3, 1fr); }
    .features-grid { grid-template-columns: repeat(4, 1fr); }
}

/* ---- Ultra-wide / 4K (1920px+) ---- */
@media (min-width: 1920px) {
    .nav-container { max-width: 1600px; }
    .section-inner { max-width: 1600px; }
    .subjects-grid { grid-template-columns: repeat(5, 1fr); }
    .subject-layout { max-width: 1500px; }
    .topic-grid { grid-template-columns: repeat(4, 1fr); }
    .hero h1 { font-size: 4.5rem; }
}

/* ---- 4K / large 4K (2560px+) ---- */
@media (min-width: 2560px) {
    .nav-container, .section-inner { max-width: 1800px; }
    .subjects-grid { grid-template-columns: repeat(6, 1fr); }
    .subject-layout { max-width: 1700px; }
    .topic-grid { grid-template-columns: repeat(5, 1fr); }
}

/* ---- Very small phones (320px) ---- */
@media (max-width: 320px) {
    html { font-size: 13px; }
    .hero h1 { font-size: 1.5rem; }
    .hero p { font-size: 0.8rem; }
    .stat-number { font-size: 1.3rem; }
    .stat-label { font-size: 0.7rem; }
    .search-box { flex-direction: column; border-radius: 12px; }
    .search-box input { padding: 0.7rem; }
    .search-box button { padding: 0.7rem; }
    .filter-btn { padding: 0.3rem 0.6rem; font-size: 0.7rem; }
    .subject-card { padding: 1rem; }
    .subject-card h3 { font-size: 0.95rem; }
    .subject-icon { width: 38px; height: 38px; }
    .subject-icon svg { width: 18px; height: 18px; }
    .level-badge { font-size: 0.55rem; padding: 0.15rem 0.5rem; }
    .nav-container { padding: 0 0.6rem; }
    .logo { font-size: 1.1rem; }
    .section { padding: 2.5rem 0.75rem; }
    .subject-header h1 { font-size: 1.4rem; }
    .level-section h2 { font-size: 1.05rem; }
    .topic-card { padding: 0.7rem; }
    .topic-card .topic-desc, .topic-card .topic-details { font-size: 0.7rem; }
    .breadcrumb { font-size: 0.7rem; }
    .code-box, .formula-box { font-size: 0.72rem; }
}

/* ---- Small phones (380px) ---- */
@media (max-width: 380px) {
    .subjects-grid { grid-template-columns: 1fr; }
    .hero-stats { gap: 1rem; }
    .contact-form, .form-group input, .form-group textarea { font-size: 0.9rem; }
}

/* ---- Tablets (600px - 900px) ---- */
@media (min-width: 600px) and (max-width: 900px) {
    .subjects-grid { grid-template-columns: repeat(2, 1fr); }
    .topic-grid { grid-template-columns: repeat(2, 1fr); }
    .features-grid { grid-template-columns: repeat(2, 1fr); }
    .category-grid { grid-template-columns: repeat(3, 1fr); }
}

/* ---- Landscape tablets ---- */
@media (min-width: 900px) and (max-width: 1100px) and (orientation: landscape) {
    .subjects-grid { grid-template-columns: repeat(3, 1fr); }
    .subject-layout { grid-template-columns: 240px 1fr; }
}

/* ---- Touch / mobile improvements ---- */
@media (hover: none) and (pointer: coarse) {
    /* Larger tap targets on touch devices */
    .filter-btn { padding: 0.7rem 1.2rem; }
    .nav-menu a { padding: 0.7rem 1rem; }
    .topic-check { width: 26px; height: 26px; }
    .sidebar-btn { padding: 0.8rem 1rem; }
    /* Disable hover-only effects that trap on touch */
    .subject-card:hover { transform: none; }
}

/* ---- Notched phones (safe areas) ---- */
@supports (padding: env(safe-area-inset-left)) {
    .navbar { padding-left: env(safe-area-inset-left); padding-right: env(safe-area-inset-right); }
    .nav-container { padding-left: calc(2rem + env(safe-area-inset-left)); padding-right: calc(2rem + env(safe-area-inset-right)); }
    .toast { bottom: calc(2rem + env(safe-area-inset-bottom)); }
    .footer { padding-left: calc(2rem + env(safe-area-inset-left)); padding-right: calc(2rem + env(safe-area-inset-right)); }
}

/* ---- Zoom / high text scaling support ---- */
@media (max-width: 768px) {
    .content-tabs { flex-wrap: wrap; }
    .content-tab { flex: 1 1 auto; justify-content: center; }
    .topic-card .topic-desc, .topic-card .topic-details { margin-left: 0; }
    .subject-card-header { flex-direction: column; gap: 0.75rem; }
    .subject-meta { flex-direction: column; align-items: flex-start; }
    .card-arrow { margin-top: 0.5rem; }
}

/* ---- Print ---- */
@media print {
    .navbar, .hero, .filter-bar, .contact-section, .footer, .subject-sidebar { display: none; }
    .subject-layout { display: block; }
    .subject-hero { background: none; color: #000; padding: 1rem 0; }
    .tab-panel { display: block !important; }
    .topic-card { break-inside: avoid; box-shadow: none; border: 1px solid #ddd; }
}

/* ---- Reduced motion ---- */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    html { scroll-behavior: auto; }
}

/* ---- High contrast / dark-ish support ---- */
@media (prefers-contrast: high) {
    .subject-card, .topic-card, .sidebar-card, .plan-card { border: 2px solid currentColor; }
}

/* ============================================================
   DAILY PRACTICE (auto-generated problems on subject pages)
   ============================================================ */
.daily-quiz {
    padding: 2.5rem 2rem;
    margin: 1.5rem auto 0;
    max-width: 1300px;
}
.daily-quiz .dq-head {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-end;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1.5rem;
    min-width: 0;
}
.daily-quiz .dq-head-text { min-width: 0; }
.daily-quiz .dq-title {
    font-size: clamp(1.2rem, 2.4vw, 1.7rem);
    font-weight: 800;
    color: #0f172a;
    line-height: 1.3;
}
.daily-quiz .dq-date { color: var(--primary); }
.daily-quiz .dq-sub { color: #64748b; font-size: 0.92rem; margin-top: 0.3rem; line-height: 1.5; }
.daily-quiz .dq-head-actions { display: flex; gap: 0.6rem; flex-wrap: wrap; }
.daily-quiz .dq-btn {
    padding: 0.6rem 1.1rem;
    border-radius: 10px;
    border: 1.5px solid #c7d2fe;
    background: #eef2ff;
    color: var(--primary);
    font-weight: 700;
    font-size: 0.85rem;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}
.daily-quiz .dq-btn:hover { background: var(--primary); color: #fff; border-color: var(--primary); transform: translateY(-1px); }

.daily-quiz .dq-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    min-width: 0;
}
.daily-quiz .dq-card {
    background: #fff;
    border: 1px solid #e2e8f0;
    border-radius: 14px;
    padding: 1.1rem 1.25rem;
    box-shadow: 0 1px 3px rgba(2, 6, 23, 0.06);
    min-width: 0;
    overflow-wrap: anywhere;
    word-break: break-word;
}
.daily-quiz .dq-top { display: flex; align-items: center; gap: 0.6rem; margin-bottom: 0.55rem; flex-wrap: wrap; }
.daily-quiz .dq-num {
    background: var(--gradient-soft);
    color: var(--primary);
    font-weight: 800;
    border-radius: 8px;
    padding: 0.18rem 0.6rem;
    font-size: 0.78rem;
}
.daily-quiz .dq-diff {
    font-size: 0.65rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 0.18rem 0.55rem;
    border-radius: 999px;
}
.daily-quiz .dq-diff.easy { background: #dcfce7; color: #166534; }
.daily-quiz .dq-diff.medium { background: #fef3c7; color: #92400e; }
.daily-quiz .dq-diff.hard { background: #fee2e2; color: #991b1b; }
.daily-quiz .dq-question { font-size: 0.92rem; font-weight: 600; color: #0f172a; line-height: 1.55; }
.daily-quiz .dq-extra { display: none; margin-top: 0.6rem; font-size: 0.85rem; line-height: 1.6; border-radius: 8px; padding: 0.55rem 0.8rem; }
.daily-quiz .dq-card.show-hint .dq-hint-extra { display: block; background: #f5f3ff; color: #4c1d95; border-left: 3px solid #7c3aed; }
.daily-quiz .dq-card.show-ans .dq-ans-extra { display: block; background: #ecfdf5; color: #065f46; border-left: 3px solid #059669; }
.daily-quiz .dq-card-actions { display: flex; gap: 0.5rem; margin-top: 0.7rem; flex-wrap: wrap; }
.daily-quiz .dq-mini {
    font-size: 0.75rem;
    padding: 0.4rem 0.75rem;
    border-radius: 8px;
    border: 1px solid #e2e8f0;
    background: #f8fafc;
    color: #334155;
    cursor: pointer;
    transition: var(--transition);
}
.daily-quiz .dq-mini:hover { background: #eef2ff; border-color: #c7d2fe; color: var(--primary); }
.daily-quiz .dq-note { margin-top: 1.1rem; font-size: 0.8rem; color: #94a3b8; overflow-wrap: anywhere; }

@media (max-width: 900px) {
    .daily-quiz { padding: 2rem 1.25rem; }
    .daily-quiz .dq-grid { grid-template-columns: 1fr; }
}
@media (min-width: 1600px) {
    .daily-quiz .dq-grid { grid-template-columns: repeat(3, 1fr); }
}

/* ============================================================
   DAILY QUIZ — MULTIPLE-CHOICE ANSWERS (A–D)
   ============================================================ */
.daily-quiz .dq-opts {
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
    margin-top: 0.7rem;
    min-width: 0;
}
.daily-quiz .dq-opt {
    display: flex;
    align-items: flex-start;
    gap: 0.6rem;
    text-align: left;
    width: 100%;
    padding: 0.55rem 0.8rem;
    border: 1.5px solid #e2e8f0;
    border-radius: 10px;
    background: #fff;
    cursor: pointer;
    font-size: 0.86rem;
    line-height: 1.45;
    color: #1e293b;
    transition: var(--transition);
    overflow-wrap: anywhere;
}
.daily-quiz .dq-opt:hover:not(:disabled) { border-color: #a5b4fc; background: #eef2ff; }
.daily-quiz .dq-opt-letter {
    flex-shrink: 0;
    width: 22px;
    height: 22px;
    border-radius: 6px;
    background: #f1f5f9;
    color: #475569;
    font-weight: 800;
    font-size: 0.72rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: 1px;
}
.daily-quiz .dq-opt.opt-correct { border-color: #16a34a; background: #f0fdf4; color: #14532d; }
.daily-quiz .dq-opt.opt-correct .dq-opt-letter { background: #16a34a; color: #fff; }
.daily-quiz .dq-opt.opt-wrong { border-color: #dc2626; background: #fef2f2; color: #7f1d1d; }
.daily-quiz .dq-opt.opt-wrong .dq-opt-letter { background: #dc2626; color: #fff; }
.daily-quiz .dq-card.is-answered .dq-opt { cursor: default; }
.daily-quiz .dq-feedback { display: none; margin-top: 0.6rem; font-size: 0.84rem; line-height: 1.55; border-radius: 8px; padding: 0.55rem 0.8rem; overflow-wrap: anywhere; }
.daily-quiz .dq-feedback:empty { display: none; }
.daily-quiz .dq-feedback.fb-good { display: block; background: #ecfdf5; color: #065f46; border-left: 3px solid #059669; }
.daily-quiz .dq-feedback.fb-bad { display: block; background: #fff1f2; color: #9f1239; border-left: 3px solid #e11d48; }
.daily-quiz .dq-score {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--primary);
    background: #eef2ff;
    border-radius: 999px;
    padding: 0.4rem 0.9rem;
    white-space: nowrap;
    border: 1.5px solid #c7d2fe;
}
.daily-quiz .dq-utc {
    font-size: 0.8rem;
    font-weight: 700;
    color: #0f172a;
    background: #f8fafc;
    border: 1.5px solid #e2e8f0;
    border-radius: 999px;
    padding: 0.4rem 0.85rem;
    white-space: nowrap;
    font-variant-numeric: tabular-nums;
    letter-spacing: 0.01em;
}
@media (max-width: 480px) {
    .daily-quiz .dq-utc { white-space: normal; font-size: 0.74rem; text-align: center; }
}

/* ============================================================
   DAILY QUIZ — WORLD-TIME CALENDAR (today + practice marks)
   ============================================================ */
.daily-quiz .dq-calbar { margin-bottom: 1.25rem; }
.daily-quiz .dq-cal {
    background: #fff;
    border: 1.5px solid #e2e8f0;
    border-radius: 14px;
    padding: 0.8rem;
    width: 100%;
    max-width: 252px;
}
.daily-quiz .dq-cal-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.4rem;
    margin-bottom: 0.5rem;
}
.daily-quiz .dq-cal-title { font-weight: 800; font-size: 0.88rem; color: #0f172a; }
.daily-quiz .dq-cal-nav {
    width: 28px;
    height: 28px;
    border-radius: 8px;
    border: 1.5px solid #e2e8f0;
    background: #f8fafc;
    color: #475569;
    font-weight: 800;
    font-size: 1rem;
    line-height: 1;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}
.daily-quiz .dq-cal-nav:hover { background: var(--primary); color: #fff; border-color: var(--primary); }
.daily-quiz .dq-cal-grid { display: grid; grid-template-columns: repeat(7, 1fr); gap: 2px; }
.daily-quiz .dq-cal-dow { font-size: 0.62rem; font-weight: 800; color: #94a3b8; text-align: center; padding: 0.15rem 0; }
.daily-quiz .dq-cal-dow.is-weekend { color: #c4b5fd; }
.daily-quiz .dq-cal-cell {
    position: relative;
    aspect-ratio: 1 / 1;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.72rem;
    font-weight: 600;
    color: #334155;
    border-radius: 8px;
    min-width: 0;
}
.daily-quiz .dq-cal-cell.is-empty { visibility: hidden; }
.daily-quiz .dq-cal-cell.is-future { color: #cbd5e1; }
.daily-quiz .dq-cal-cell.is-today {
    background: var(--primary);
    color: #fff;
    font-weight: 800;
    box-shadow: 0 4px 10px rgba(79, 70, 229, 0.35);
}
.daily-quiz .dq-cal-cell.is-done:not(.is-today) { background: #ecfdf5; color: #047857; }
.daily-quiz .dq-cal-cell.is-done::after {
    content: '';
    position: absolute;
    bottom: 2px;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    height: 4px;
    border-radius: 50%;
    background: #10b981;
}
.daily-quiz .dq-cal-cell.is-today.is-done::after { background: #fff; }
.daily-quiz .dq-cal-foot { margin-top: 0.55rem; font-size: 0.74rem; color: #64748b; line-height: 1.4; }

/* ============================================================
   SAMPLE LESSONS (homepage, free preview)
   ============================================================ */
.samples-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(255px, 1fr));
    gap: 1.25rem;
    min-width: 0;
}
.sample-card {
    background: #fff;
    border: 1px solid #e2e8f0;
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: 0 1px 3px rgba(2, 6, 23, 0.06);
    min-width: 0;
    overflow-wrap: anywhere;
}
.sample-top { display: flex; justify-content: space-between; align-items: center; gap: 0.5rem; margin-bottom: 0.7rem; }
.sample-subject {
    background: var(--gradient-soft);
    color: var(--primary);
    font-size: 0.68rem;
    font-weight: 800;
    padding: 0.22rem 0.65rem;
    border-radius: 999px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    white-space: nowrap;
}
.sample-time { color: #94a3b8; font-size: 0.72rem; font-weight: 700; white-space: nowrap; }
.sample-card h3 { font-size: 1.05rem; margin-bottom: 0.5rem; color: #0f172a; }
.sample-text { color: #64748b; font-size: 0.87rem; line-height: 1.65; }
.sample-check { margin-top: 1rem; background: #f8fafc; border: 1px dashed #cbd5e1; border-radius: 10px; padding: 0.85rem; }
.sample-q { font-size: 0.85rem; font-weight: 700; color: #0f172a; margin-bottom: 0.5rem; }
.sample-ans {
    display: none;
    margin-top: 0.5rem;
    font-size: 0.83rem;
    color: #065f46;
    background: #ecfdf5;
    border-left: 3px solid #059669;
    padding: 0.5rem 0.7rem;
    border-radius: 6px;
    line-height: 1.5;
}
.sample-card.show-ans .sample-ans { display: block; }
.sample-btn {
    margin-top: 0.5rem;
    font-size: 0.75rem;
    padding: 0.4rem 0.75rem;
    border-radius: 8px;
    border: 1px solid #e2e8f0;
    background: #fff;
    color: #334155;
    cursor: pointer;
    transition: var(--transition);
}
.sample-btn:hover { background: #eef2ff; border-color: #c7d2fe; color: var(--primary); }
.samples-cta { margin-top: 2rem; text-align: center; display: flex; flex-direction: column; align-items: center; gap: 1rem; }
.samples-cta-text { color: #64748b; font-size: 0.92rem; max-width: 620px; line-height: 1.6; }
.samples-cta-btn {
    display: inline-block;
    background: var(--gradient);
    color: #fff;
    font-weight: 800;
    padding: 0.85rem 2rem;
    border-radius: 12px;
    text-decoration: none;
    font-size: 0.95rem;
    transition: var(--transition);
}
.samples-cta-btn:hover { transform: translateY(-2px); box-shadow: 0 10px 30px rgba(79, 70, 229, 0.35); }

/* ============================================================
   SCREENSHOT / COPY PROTECTION
   ============================================================ */
body.guard-select, body.guard-select * { user-select: none; -webkit-user-select: none; }
body.guard-select input, body.guard-select textarea, body.guard-select .guard-allow { user-select: text; -webkit-user-select: text; }
#screen-guard {
    position: fixed;
    inset: 0;
    z-index: 99999;
    display: none;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 0.6rem;
    background: rgba(15, 23, 42, 0.97);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    color: #fff;
    text-align: center;
    padding: 2rem;
    cursor: default;
}
body.guard-on #screen-guard { display: flex; }
#screen-guard .sg-icon { font-size: 3.2rem; }
#screen-guard .sg-title { font-size: 1.3rem; font-weight: 800; }
#screen-guard .sg-sub { color: #94a3b8; font-size: 0.9rem; max-width: 420px; line-height: 1.6; }