:root {
    --bg: #070d1a;
    --accent: #38bdf8;
    --accent2: #818cf8;
    --text: #f1f5f9;
    --muted: #94a3b8;
    --glass: rgba(15, 25, 50, 0.6);
    --border: rgba(148, 163, 184, 0.1);
    --card-bg: rgba(15, 25, 50, 0.8);
}

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

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg);
    color: var(--text);
    overflow-x: hidden;
    line-height: 1.7;
}

/* --- Background Glows --- */
.bg-glow {
    position: fixed;
    border-radius: 50%;
    filter: blur(120px);
    pointer-events: none;
    z-index: 0;
    opacity: 0.3;
}
.bg-glow-1 {
    width: 600px; height: 600px;
    background: radial-gradient(circle, #1e40af, transparent);
    top: -100px; left: -100px;
    animation: floatA 15s ease-in-out infinite alternate;
}
.bg-glow-2 {
    width: 500px; height: 500px;
    background: radial-gradient(circle, #4f46e5, transparent);
    bottom: 0; right: -100px;
    animation: floatB 18s ease-in-out infinite alternate;
}
@keyframes floatA { to { transform: translate(80px, 60px); } }
@keyframes floatB { to { transform: translate(-80px, -60px); } }

/* Seismic wave decoration */
.seismic-wave {
    position: fixed;
    bottom: 0; left: 0;
    width: 100%; height: 200px;
    background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1440 200'%3E%3Cpath fill='%2338bdf808' d='M0,100 C200,40 300,160 500,80 C700,0 800,120 1000,60 C1200,0 1350,80 1440,50 L1440,200 L0,200Z'/%3E%3C/svg%3E") no-repeat bottom;
    background-size: cover;
    pointer-events: none;
    z-index: 0;
}

/* --- Navbar --- */
#navbar {
    position: fixed; top: 0; left: 0;
    width: 100%; z-index: 1000;
    padding: 12px 0;
    background: rgba(7, 13, 26, 0.85);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: all 0.3s;
}
.nav-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.nav-brand {
    font-weight: 700;
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: 8px;
}
.nav-dot {
    width: 8px; height: 8px;
    background: var(--accent);
    border-radius: 50%;
    box-shadow: 0 0 10px var(--accent);
    animation: blink 2s infinite;
}
@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.3; }
}
nav a {
    color: var(--muted);
    text-decoration: none;
    margin-left: 24px;
    font-size: 0.9rem;
    font-weight: 600;
    transition: color 0.3s;
}
nav a:hover { color: var(--accent); }

/* --- Hero --- */
#hero {
    position: relative; z-index: 1;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 120px 20px 60px;
}
.badge {
    display: inline-block;
    padding: 6px 18px;
    background: rgba(56, 189, 248, 0.1);
    border: 1px solid rgba(56, 189, 248, 0.3);
    border-radius: 30px;
    font-size: 0.8rem;
    color: var(--accent);
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 24px;
}
#hero h1 {
    font-size: clamp(2.5rem, 6vw, 5rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 20px;
}
.gradient-text {
    background: linear-gradient(135deg, var(--accent), var(--accent2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero-sub {
    color: var(--muted);
    font-size: 1.1rem;
    max-width: 580px;
    margin-bottom: 36px;
}
.hero-btns { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; margin-bottom: 60px; }
.btn {
    padding: 13px 30px;
    border-radius: 50px;
    font-weight: 700;
    font-size: 0.95rem;
    text-decoration: none;
    transition: all 0.3s;
}
.btn-primary {
    background: linear-gradient(135deg, var(--accent), var(--accent2));
    color: #fff;
    box-shadow: 0 8px 30px rgba(56,189,248,0.35);
}
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 15px 40px rgba(56,189,248,0.5); }
.btn-ghost {
    background: transparent;
    color: var(--text);
    border: 1px solid var(--border);
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

/* Hero stats */
.hero-stats {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
}
.stat-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 20px 28px;
    text-align: center;
    backdrop-filter: blur(10px);
    min-width: 130px;
}
.stat-num {
    display: block;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--accent);
}
.stat-label {
    display: block;
    font-size: 0.75rem;
    color: var(--muted);
    margin-top: 4px;
}

/* --- Sections --- */
.section-wrap {
    position: relative; z-index: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 80px 30px;
}
.section-header {
    text-align: center;
    margin-bottom: 60px;
}
.section-tag {
    display: inline-block;
    padding: 4px 14px;
    background: rgba(129, 140, 248, 0.1);
    border: 1px solid rgba(129, 140, 248, 0.3);
    border-radius: 30px;
    font-size: 0.75rem;
    color: var(--accent2);
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 16px;
}
.section-header h2 {
    font-size: clamp(1.8rem, 4vw, 2.8rem);
    font-weight: 800;
    margin-bottom: 12px;
}
.section-header p { color: var(--muted); font-size: 1rem; }

/* --- Feature Block --- */
.feature-block {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    align-items: center;
    margin-bottom: 60px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 24px;
    padding: 40px;
    backdrop-filter: blur(10px);
}
.feature-text h3 { font-size: 1.5rem; margin-bottom: 16px; }
.feature-text p { color: var(--muted); margin-bottom: 20px; }
.feature-list { list-style: none; }
.feature-list li {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 6px 0;
    color: var(--muted);
    font-size: 0.9rem;
}
.dot-accent {
    width: 6px; height: 6px;
    background: var(--accent);
    border-radius: 50%;
    flex-shrink: 0;
}
.feature-media img { width: 100%; border-radius: 12px; }

/* --- Media Row --- */
.media-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    margin-bottom: 60px;
}
.media-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 16px;
    overflow: hidden;
}
.media-img {
    width: 100%;
    height: 250px;
    object-fit: cover;
    display: block;
}
.media-caption {
    padding: 12px 16px;
    font-size: 0.8rem;
    color: var(--muted);
    text-align: center;
}

/* --- Steps --- */
.steps-block {
    margin-bottom: 60px;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 24px;
    padding: 40px;
    backdrop-filter: blur(10px);
}
.steps-block h3 { font-size: 1.5rem; margin-bottom: 30px; }
.steps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
}
.step-card {
    background: rgba(255,255,255,0.03);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 20px;
    transition: border-color 0.3s, transform 0.3s;
}
.step-card:hover { border-color: var(--accent); transform: translateY(-4px); }
.step-num {
    font-size: 2rem;
    font-weight: 800;
    color: var(--accent);
    opacity: 0.5;
    margin-bottom: 10px;
    display: block;
}
.step-card h4 { margin-bottom: 8px; font-size: 1rem; }
.step-card p { font-size: 0.85rem; color: var(--muted); }
.step-card code {
    background: rgba(56,189,248,0.15);
    padding: 1px 6px;
    border-radius: 4px;
    color: var(--accent);
    font-size: 0.8rem;
}

/* --- Videos --- */
.video-section {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 24px;
    padding: 40px;
    backdrop-filter: blur(10px);
}
.video-section h3 { font-size: 1.5rem; margin-bottom: 30px; }
.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}
.video-card {
    background: rgba(255,255,255,0.03);
    border: 1px solid var(--border);
    border-radius: 12px;
    overflow: hidden;
}
.video-card video {
    width: 100%;
    display: block;
    max-height: 220px;
    object-fit: cover;
    background: #000;
}

/* --- Homework Grid --- */
.hw-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 24px;
}
.hw-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 20px;
    padding: 28px;
    backdrop-filter: blur(10px);
    transition: transform 0.3s, border-color 0.3s;
}
.hw-card:hover { transform: translateY(-5px); border-color: rgba(56,189,248,0.3); }
.hw-card-final {
    border-color: rgba(56,189,248,0.4);
    background: linear-gradient(135deg, rgba(56,189,248,0.05), rgba(129,140,248,0.05));
    grid-column: 1 / -1;
}
.hw-header { margin-bottom: 12px; }
.hw-num {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--accent);
    background: rgba(56,189,248,0.1);
    padding: 3px 10px;
    border-radius: 20px;
    margin-bottom: 8px;
}
.hw-card h3 { font-size: 1rem; font-weight: 700; }
.hw-card p { color: var(--muted); font-size: 0.9rem; margin-bottom: 16px; }
.hw-imgs {
    display: flex;
    gap: 10px;
    margin-top: 14px;
    flex-wrap: wrap;
}
.hw-img {
    width: calc(33.333% - 7px);
    border-radius: 8px;
    object-fit: cover;
    aspect-ratio: 16/9;
}
.hw-link {
    display: inline-block;
    color: var(--accent);
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 600;
    padding: 6px 14px;
    border: 1px solid rgba(56,189,248,0.3);
    border-radius: 20px;
    transition: all 0.3s;
}
.hw-link:hover { background: rgba(56,189,248,0.1); }

/* --- Footer --- */
footer {
    position: relative; z-index: 1;
    text-align: center;
    padding: 40px 20px;
    color: var(--muted);
    font-size: 0.85rem;
    border-top: 1px solid var(--border);
}

/* --- Animations --- */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 1s ease forwards;
}
.fade-in:nth-child(2) { animation-delay: 0.3s; }

@keyframes fadeInUp {
    to { opacity: 1; transform: translateY(0); }
}

.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* --- Responsive --- */
@media (max-width: 768px) {
    .feature-block { grid-template-columns: 1fr; }
    .media-row { grid-template-columns: 1fr; }
    nav { display: none; }
    .hw-card-final { grid-column: auto; }
    .hw-img { width: 100%; }
}