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

:root {
    --bg:       #f0f7ff;
    --surface:  #ffffff;
    --surface2: #e0f1ff;
    --accent:   #0ea5e9;
    --accent-d: #0284c7;
    --accent-l: #38bdf8;
    --text:     #0f172a;
    --muted:    #64748b;
    --border:   rgba(14,165,233,0.15);
    --shadow:   0 4px 24px rgba(14,165,233,0.15);
    --shadow-md:0 12px 48px rgba(14,165,233,0.20);
    --radius:   16px;
}

html { scroll-behavior: smooth; }

body {
    font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
    background: linear-gradient(135deg, var(--bg), #dbeafe);
    color: var(--text);
    line-height: 1.75;
}

a { color: inherit; text-decoration: none; }
a:hover { text-decoration: none; }
strong { font-weight: 700; }

/* ── NAV ── */
nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255,255,255,0.9);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    padding: 0 1.5rem;
    box-shadow: var(--shadow);
}
.nav-inner {
    max-width: 1100px;
    margin: 0 auto;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.brand {
    font-size: 1.1rem;
    font-weight: 800;
    letter-spacing: -0.02em;
}
.brand span { color: var(--accent); }

/* ── HERO ── */
.hero {
    min-height: 90vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    padding: 6rem 1.5rem 4rem;
}
.hero-bg {
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 80% 50% at 50% 0%, rgba(14,165,233,0.15), transparent 70%),
                radial-gradient(ellipse 60% 40% at 10% 90%, rgba(56,189,248,0.1), transparent 60%);
    pointer-events: none;
}
.hero-inner {
    max-width: 1100px;
    margin: 0 auto;
    width: 100%;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    position: relative;
    z-index: 1;
}
.hero-eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(14,165,233,0.1);
    border: 1px solid rgba(14,165,233,0.3);
    border-radius: 999px;
    padding: 0.35rem 1.1rem;
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--accent);
    letter-spacing: 0.04em;
    text-transform: uppercase;
    margin-bottom: 1.5rem;
}
.hero h1 {
    font-size: clamp(2.2rem, 5vw, 3.5rem);
    font-weight: 900;
    line-height: 1.15;
    letter-spacing: -0.03em;
    margin-bottom: 1.25rem;
}
.hero h1 .highlight {
    background: linear-gradient(135deg, var(--accent), var(--accent-l));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero-desc {
    font-size: 1.1rem;
    color: var(--muted);
    max-width: 50ch;
    margin-bottom: 2rem;
    line-height: 1.8;
}
.hero-cta {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.85rem 1.8rem;
    border-radius: 11px;
    font-size: 0.95rem;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    border: none;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary {
    background: linear-gradient(135deg, var(--accent), var(--accent-l));
    color: white;
}
.btn-primary:hover { box-shadow: 0 8px 32px rgba(14,165,233,0.35); }
.btn-ghost {
    background: transparent;
    border: 1.5px solid var(--border);
    color: var(--text);
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

/* Hero visual */
.hero-visual {
    display: flex;
    justify-content: center;
}
.code-window {
    background: #0d1117;
    border: 1px solid rgba(14,165,233,0.2);
    border-radius: var(--radius);
    padding: 1.5rem;
    width: 100%;
    max-width: 420px;
    box-shadow: var(--shadow-md);
    font-family: "Consolas", "Courier New", monospace;
    font-size: 0.85rem;
    line-height: 1.8;
}
.win-dots {
    display: flex;
    gap: 6px;
    margin-bottom: 1rem;
}
.win-dots span {
    width: 12px; height: 12px;
    border-radius: 50%;
}
.win-dots .r { background: #ff5f57; }
.win-dots .y { background: #febc2e; }
.win-dots .g { background: #28c840; }
.code-line { display: flex; gap: 0.5rem; }
.ln  { color: #4b5563; min-width: 1.5rem; text-align: right; user-select: none; }
.k  { color: #c792ea; }
.fn { color: #82aaff; }
.s  { color: #c3e88d; }
.p  { color: #89ddff; }

/* ── STATS ── */
.stats {
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    padding: 2rem 1.5rem;
    background: rgba(255,255,255,0.4);
}
.stats-inner {
    max-width: 1100px;
    margin: 0 auto;
    display: flex;
    justify-content: center;
    gap: 4rem;
    flex-wrap: wrap;
}
.stat { text-align: center; }
.stat-num {
    font-size: 2rem;
    font-weight: 900;
    letter-spacing: -0.04em;
    color: var(--accent);
}
.stat-label {
    font-size: 0.85rem;
    color: var(--muted);
    margin-top: 0.25rem;
}

/* ── COURSES SECTION ── */
.section {
    padding: 5rem 1.5rem;
    max-width: 1100px;
    margin: 0 auto;
}
.section-head {
    text-align: center;
    margin-bottom: 3.5rem;
}
.section-tag {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 0.75rem;
}
.section-head h2 {
    font-size: clamp(1.6rem, 3.5vw, 2.4rem);
    font-weight: 900;
    letter-spacing: -0.03em;
    margin-bottom: 0.75rem;
}
.section-head p {
    color: var(--muted);
    max-width: 60ch;
    margin: 0 auto;
    font-size: 1rem;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 2rem;
}
.course-card {
    background: var(--surface);
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
    position: relative;
    overflow: hidden;
}
.course-card::before {
    content: "";
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent), var(--accent-l));
    border-radius: var(--radius) var(--radius) 0 0;
}
.course-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
    box-shadow: var(--shadow-md);
}
.course-icon {
    width: 52px; height: 52px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    background: linear-gradient(135deg, rgba(14,165,233,0.15), rgba(56,189,248,0.1));
    color: var(--accent);
}
.course-badges {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}
.badge {
    font-size: 0.7rem;
    font-weight: 700;
    padding: 0.25rem 0.75rem;
    border-radius: 999px;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}
.badge-available {
    background: rgba(14,165,233,0.12);
    color: var(--accent);
    border: 1px solid var(--border);
}
.badge-soon {
    background: rgba(251,146,60,0.12);
    color: #ea580c;
    border: 1px solid rgba(251,146,60,0.3);
}

.course-title {
    font-size: 1.2rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    line-height: 1.3;
}
.course-desc {
    font-size: 0.92rem;
    color: var(--muted);
    flex: 1;
    line-height: 1.7;
}
.course-meta {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.8rem;
    color: var(--muted);
}
.course-link {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-size: 0.9rem;
    font-weight: 700;
    color: var(--accent);
    transition: gap 0.18s;
    margin-top: 0.5rem;
}
.course-link:hover { gap: 0.7rem; }
.course-link.disabled {
    color: var(--muted);
    pointer-events: none;
}

/* ── FOOTER ── */
footer {
    text-align: center;
    padding: 2.5rem 1.5rem;
    color: var(--muted);
    font-size: 0.85rem;
    border-top: 1px solid var(--border);
    margin-top: 3rem;
}
footer a { color: var(--accent); }
footer a:hover { text-decoration: underline; }

/* ── RESPONSIVE ── */
@media (max-width: 768px) {
    .hero-inner {
        grid-template-columns: 1fr;
        gap: 2.5rem;
    }
    .hero-visual { order: -1; }
    .hero h1 { font-size: 2rem; }
    .stats-inner { gap: 2rem; }
    .courses-grid { grid-template-columns: 1fr; }
}