:root {
    --background: #0b1020;
    --surface: #121a2d;
    --surface-light: #19243a;
    --primary: #38bdf8;
    --text: #f1f5f9;
    --muted: #94a3b8;
    --border: #26334a;
}

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

html {
    scroll-behavior: smooth;
}

body {
    background: var(--background);
    color: var(--text);
    font-family: Arial, Helvetica, sans-serif;
    line-height: 1.6;
}

a {
    color: inherit;
    text-decoration: none;
}

.navbar {
    min-height: 76px;
    padding: 16px 7%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border);
}

.logo {
    font-size: 25px;
    font-weight: 800;
    letter-spacing: 2px;
}

.logo span {
    color: var(--primary);
}

.navbar nav {
    display: flex;
    gap: 30px;
    color: var(--muted);
}

.navbar nav a:hover,
.login-link:hover {
    color: var(--primary);
}

.nav-actions,
.hero-actions {
    display: flex;
    align-items: center;
    gap: 18px;
}

.login-link {
    color: var(--muted);
}

.btn {
    display: inline-block;
    padding: 11px 21px;
    border-radius: 8px;
    font-weight: 700;
    transition: 0.2s;
}

.btn-primary {
    background: var(--primary);
    color: #07111e;
}

.btn-primary:hover {
    background: #7dd3fc;
    transform: translateY(-2px);
}

.btn-secondary {
    border: 1px solid var(--border);
    color: var(--text);
}

.btn-secondary:hover {
    background: var(--surface-light);
}

.hero {
    min-height: 590px;
    padding: 100px 9%;
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    align-items: center;
    gap: 60px;
}

.eyebrow {
    color: var(--primary);
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 2px;
}

.hero h1 {
    font-size: clamp(38px, 5vw, 62px);
    line-height: 1.15;
    margin: 20px 0;
}

.hero h1 span {
    color: var(--primary);
}

.hero-content > p {
    color: var(--muted);
    max-width: 520px;
    margin-bottom: 30px;
}

.hero-note {
    margin-top: 28px;
    color: var(--muted);
    font-size: 13px;
}

.code-card {
    background: #080d19;
    border: 1px solid var(--border);
    border-radius: 14px;
    overflow: hidden;
    box-shadow: 0 20px 60px #0005;
}

.code-header {
    padding: 15px 20px;
    display: flex;
    gap: 20px;
    align-items: center;
    border-bottom: 1px solid var(--border);
    color: var(--muted);
    font-size: 13px;
}

.window-dots {
    display: flex;
    gap: 7px;
}

.window-dots span {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #ef4444;
}

.window-dots span:nth-child(2) {
    background: #fbbf24;
}

.window-dots span:nth-child(3) {
    background: #22c55e;
}

.code-card pre {
    padding: 28px;
    overflow-x: auto;
    font-size: 13px;
    line-height: 2;
    color: #e2e8f0;
}

.code-purple { color: #c084fc; }
.code-blue { color: #38bdf8; }
.code-green { color: #4ade80; }
.code-comment { color: #64748b; }

.features,
.courses {
    padding: 90px 9%;
}

.features {
    background: var(--surface);
}

.section-heading {
    text-align: center;
    margin-bottom: 45px;
}

.section-heading h2 {
    font-size: 34px;
    margin: 12px 0;
}

.section-heading p {
    color: var(--muted);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.feature-card {
    background: var(--background);
    padding: 30px;
    border: 1px solid var(--border);
    border-radius: 12px;
}

.feature-icon {
    color: var(--primary);
    font-size: 25px;
    font-weight: bold;
    margin-bottom: 20px;
}

.feature-card h3 {
    margin-bottom: 10px;
}

.feature-card p,
.course-item p {
    color: var(--muted);
    font-size: 14px;
}

.course-list {
    max-width: 850px;
    margin: auto;
}

.course-item {
    padding: 20px;
    display: flex;
    align-items: center;
    gap: 20px;
    border-bottom: 1px solid var(--border);
}

.course-number {
    background: var(--surface-light);
    color: var(--primary);
    width: 42px;
    height: 42px;
    display: grid;
    place-items: center;
    border-radius: 9px;
    font-weight: bold;
}

.course-item h3 {
    font-size: 16px;
}

.course-item > div {
    flex: 1;
}

.course-status {
    color: var(--muted);
    font-size: 12px;
}

.about {
    padding: 75px 20px;
    text-align: center;
    background: var(--surface);
}

.about h2 {
    font-size: 32px;
    margin-bottom: 10px;
}

.about p,
footer p {
    color: var(--muted);
}

footer {
    padding: 30px 7%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-top: 1px solid var(--border);
}

@media (max-width: 850px) {
    .hero {
        grid-template-columns: 1fr;
        padding: 70px 7%;
    }

    .feature-grid {
        grid-template-columns: 1fr;
    }

    .navbar nav {
        display: none;
    }
}

@media (max-width: 520px) {
    .nav-actions {
        gap: 10px;
    }

    .navbar {
        padding: 15px 5%;
    }

    .hero-actions {
        flex-wrap: wrap;
    }

    .course-item {
        gap: 12px;
    }

    .course-status {
        display: none;
    }

    footer {
        flex-direction: column;
        gap: 12px;
        text-align: center;
    }
}