:root {
    --bg: #f6f7fb;
    --sidebar-bg: #ffffff;
    --card-bg: #ffffff;
    --text: #1a1d27;
    --muted: #6b7280;
    --accent: #f6821f;
    --border: #e5e7eb;
    --shadow: 0 4px 24px rgba(17, 24, 39, 0.06);
}
@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0f1117;
        --sidebar-bg: #161922;
        --card-bg: #1b1f2b;
        --text: #e5e7eb;
        --muted: #9ca3af;
        --accent: #f6821f;
        --border: #262b38;
        --shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
    }
}
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    display: flex;
    min-height: 100vh;
    transition: background 0.3s, color 0.3s;
}

.sidebar {
    width: 240px;
    flex-shrink: 0;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border);
    padding: 2rem 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
    position: sticky;
    top: 0;
    height: 100vh;
}
.logo {
    font-size: 1.25rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.logo-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--accent);
}
nav {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    flex: 1;
}
nav a {
    color: var(--muted);
    text-decoration: none;
    padding: 0.55rem 0.75rem;
    border-radius: 8px;
    font-size: 0.95rem;
    transition: all 0.2s;
}
nav a:hover {
    color: var(--text);
    background: var(--bg);
}
nav a.active {
    color: var(--accent);
    background: var(--bg);
    font-weight: 600;
}
.sidebar-footer {
    font-size: 0.75rem;
    color: var(--muted);
    line-height: 1.6;
}
.badge {
    display: inline-block;
    padding: 0.15rem 0.5rem;
    border-radius: 999px;
    font-size: 0.7rem;
    background: rgba(246, 130, 31, 0.15);
    color: var(--accent);
    font-weight: 600;
}

.main {
    flex: 1;
    padding: 3rem 2.5rem;
    max-width: 760px;
}
.main h1 {
    font-size: 2rem;
    margin-bottom: 1.25rem;
}
.card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    box-shadow: var(--shadow);
    padding: 1.5rem 1.75rem;
    margin-bottom: 1.25rem;
}
.card h2 {
    font-size: 1.05rem;
    margin-bottom: 0.75rem;
}
.card p {
    color: var(--muted);
    font-size: 0.95rem;
    line-height: 1.8;
}
.counter {
    display: flex;
    align-items: baseline;
    gap: 0.75rem;
    margin-top: 0.25rem;
}
.counter-number {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--accent);
    font-variant-numeric: tabular-nums;
}
.counter-label {
    color: var(--muted);
    font-size: 0.95rem;
}
.tech-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 0.5rem;
}
.tech-item {
    font-size: 0.8rem;
    padding: 0.3rem 0.75rem;
    border-radius: 999px;
    border: 1px solid var(--border);
    color: var(--muted);
}

@media (max-width: 768px) {
    body {
        flex-direction: column;
    }
    .sidebar {
        width: 100%;
        height: auto;
        position: static;
        flex-direction: row;
        align-items: center;
        padding: 1rem 1.25rem;
        gap: 1rem;
        border-right: none;
        border-bottom: 1px solid var(--border);
    }
    nav {
        flex-direction: row;
        flex: none;
    }
    .sidebar-footer {
        display: none;
    }
    .main {
        padding: 2rem 1.25rem;
    }
}