/* --- VARIABLES --- */
:root {
    --bg-dark: #0d1117; /* GitHub Dark */
    --bg-card: #161b22; /* GitHub Card */
    --accent: #58a6ff; /* Code Blue */
    --accent-green: #3fb950; /* Code Green */
    --text-main: #c9d1d9;
    --text-muted: #8b949e;
    --border: #30363d;
    --font-ui: 'Inter', sans-serif;
    --font-code: 'Fira Code', monospace;
}

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

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    font-family: var(--font-ui);
    line-height: 1.6;
}

.container {
    width: 90%;
    max-width: 1100px;
    margin: 0 auto;
}

a {
    text-decoration: none;
    transition: 0.3s;
}

/* NAV */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 5%;
    border-bottom: 1px solid var(--border);
    background: rgba(13, 17, 23, 0.95);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    font-weight: 800;
    font-size: 1.2rem;
    color: #fff;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.py-icon {
    font-size: 1.5rem;
}

.back-link {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 600;
}

    .back-link:hover {
        color: var(--accent);
    }

/* HERO */
.hero {
    padding: 6rem 0;
    border-bottom: 1px solid var(--border);
}

    .hero .container {
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: 4rem;
        align-items: center;
    }

.tag {
    color: var(--accent-green);
    font-family: var(--font-code);
    font-size: 0.8rem;
    border: 1px solid var(--border);
    padding: 0.3rem 0.8rem;
    border-radius: 50px;
}

.hero h1 {
    font-size: 3rem;
    color: #fff;
    margin: 1.5rem 0;
    line-height: 1.2;
}

.highlight {
    color: #fff;
    text-decoration: underline;
    text-decoration-color: var(--accent);
}

.highlight-code {
    font-family: var(--font-code);
    color: var(--accent);
    background: rgba(88, 166, 255, 0.1);
    padding: 0 0.5rem;
    border-radius: 4px;
}

.lead {
    font-size: 1.1rem;
    color: var(--text-muted);
    margin-bottom: 2rem;
    max-width: 500px;
}

.btn-primary {
    background: var(--accent);
    color: #000;
    padding: 0.8rem 1.5rem;
    border-radius: 6px;
    font-weight: 700;
    display: inline-block;
}

    .btn-primary:hover {
        background: #79c0ff;
        transform: translateY(-2px);
    }

/* CODE WINDOW (Visual) */
.code-window {
    background: #0d1117;
    border: 1px solid var(--border);
    border-radius: 12px;
    box-shadow: 0 20px 50px rgba(0,0,0,0.5);
    overflow: hidden;
    font-family: var(--font-code);
}

.window-header {
    background: #161b22;
    padding: 0.8rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    border-bottom: 1px solid var(--border);
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.red {
    background: #ff5f56;
}

.yellow {
    background: #ffbd2e;
}

.green {
    background: #27c93f;
}

.filename {
    margin-left: 1rem;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.code-block {
    padding: 1.5rem;
    font-size: 0.85rem;
    line-height: 1.7;
    color: #c9d1d9;
    overflow-x: auto;
}

.keyword {
    color: #ff7b72;
}
/* Python Pink */
.number {
    color: #79c0ff;
}
/* Blue */
.string {
    color: #a5d6ff;
}
/* Light Blue */
.comment {
    color: #8b949e;
    font-style: italic;
}

.func {
    color: #d2a8ff;
}
/* Purple */

/* PROBLEM SECTION */
.section-problem {
    padding: 5rem 0;
    background: var(--bg-card);
}

.problem-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 4rem;
}

.text-col h2 {
    font-size: 2rem;
    color: #fff;
    margin-bottom: 1rem;
}

.stat-col {
    display: flex;
    gap: 2rem;
}

.stat-card h3 {
    font-size: 3rem;
    color: var(--accent);
    font-weight: 800;
    margin: 0;
    line-height: 1;
}

.stat-card p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
}

/* ROADMAP */
.section-roadmap {
    padding: 6rem 0;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

    .section-header h2 {
        font-size: 2.5rem;
        color: #fff;
        margin-bottom: 0.5rem;
    }

.timeline {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.module-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
    transition: 0.3s;
}

    .module-card:hover {
        border-color: var(--accent);
        transform: translateY(-5px);
    }

.week-badge {
    background: #21262d;
    color: var(--text-muted);
    padding: 0.5rem 1.5rem;
    font-family: var(--font-code);
    font-size: 0.8rem;
    border-bottom: 1px solid var(--border);
    font-weight: 700;
}

.module-content {
    padding: 1.5rem;
}

    .module-content h3 {
        color: #fff;
        margin-bottom: 0.5rem;
    }

    .module-content p {
        font-size: 0.9rem;
        color: var(--text-muted);
        margin-bottom: 1.5rem;
    }

.topics {
    list-style: none;
    padding: 0;
}

    .topics li {
        font-size: 0.85rem;
        margin-bottom: 0.5rem;
        padding-left: 1rem;
        position: relative;
        color: var(--text-main);
    }

        .topics li::before {
            content: '>';
            color: var(--accent);
            position: absolute;
            left: 0;
            font-family: var(--font-code);
            font-weight: 700;
        }

.highlight-card {
    border-color: var(--accent-green);
}

    .highlight-card .week-badge {
        color: var(--accent-green);
    }

/* RESULTS */
.section-results {
    padding: 6rem 0;
    background: var(--bg-card);
    border-top: 1px solid var(--border);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-top: 3rem;
}

.result-card {
    background: var(--bg-dark);
    padding: 2rem;
    border-radius: 8px;
    border: 1px solid var(--border);
    text-align: center;
}

    .result-card .icon {
        font-size: 2rem;
        margin-bottom: 1rem;
    }

    .result-card h4 {
        color: #fff;
        margin-bottom: 0.5rem;
    }

    .result-card p {
        font-size: 0.9rem;
        color: var(--text-muted);
    }

/* FOOTER */
footer {
    padding: 4rem 0;
    border-top: 1px solid var(--border);
}

.footer-flex {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

footer h3 {
    color: #fff;
    font-size: 1.2rem;
    margin-bottom: 0.2rem;
}

footer p {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* RESPONSIVE */
@media (max-width: 900px) {
    .hero .container, .problem-grid {
        grid-template-columns: 1fr;
    }

    .hero-visual {
        order: -1;
        margin-bottom: 2rem;
    }

    .stat-col {
        flex-direction: row;
        justify-content: flex-start;
    }

    .grid-3 {
        grid-template-columns: 1fr;
    }

    .footer-flex {
        flex-direction: column;
        text-align: center;
        gap: 2rem;
    }
}