:root {
    --bg: #f5f7fa;
    --surface: #ffffff;
    --text: #20242a;
    --muted: #68707c;
    --border: #e5e9ef;
    --accent: #315efb;
    --accent-soft: #edf2ff;
    --shadow: 0 12px 36px rgba(30, 42, 65, 0.07);
    font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont,
                 "Segoe UI", "Microsoft YaHei", sans-serif;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    line-height: 1.75;
}

a {
    color: var(--accent);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

.container {
    width: min(920px, calc(100% - 40px));
    margin: 0 auto;
}

.site-header {
    background: rgba(255, 255, 255, 0.94);
    border-bottom: 1px solid var(--border);
}

.header-inner {
    min-height: 68px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.brand {
    color: var(--text);
    font-size: 20px;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.brand:hover {
    text-decoration: none;
}

nav {
    display: flex;
    gap: 22px;
    font-size: 15px;
}

nav a {
    color: var(--muted);
}

nav a:hover,
nav a.active {
    color: var(--accent);
    text-decoration: none;
}

main {
    padding: 54px 0 72px;
}

.hero {
    padding: 44px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 20px;
    box-shadow: var(--shadow);
}

.hero-label {
    display: inline-block;
    margin-bottom: 12px;
    padding: 4px 11px;
    border-radius: 999px;
    background: var(--accent-soft);
    color: var(--accent);
    font-size: 13px;
}

.hero h1 {
    margin: 0 0 14px;
    font-size: clamp(30px, 5vw, 45px);
    line-height: 1.2;
    letter-spacing: -0.04em;
}

.hero p {
    max-width: 680px;
    margin: 0;
    color: var(--muted);
    font-size: 17px;
}

.section-title {
    margin: 48px 0 20px;
    font-size: 23px;
}

.post-list {
    display: grid;
    gap: 16px;
}

.post-card {
    display: block;
    padding: 25px 28px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 15px;
    color: var(--text);
    transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.post-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    text-decoration: none;
}

.post-meta {
    margin-bottom: 7px;
    color: var(--muted);
    font-size: 13px;
}

.post-card h2 {
    margin: 0 0 8px;
    font-size: 20px;
}

.post-card p {
    margin: 0;
    color: var(--muted);
}

.content-card {
    padding: 38px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 18px;
    box-shadow: var(--shadow);
}

.content-card h1 {
    margin-top: 0;
    line-height: 1.3;
}

.content-card h2 {
    margin-top: 34px;
}

.content-card p,
.content-card li {
    color: #4f5865;
}

.note {
    padding: 15px 18px;
    border-left: 4px solid var(--accent);
    background: var(--accent-soft);
    border-radius: 6px;
}

.site-footer {
    padding: 27px 0;
    border-top: 1px solid var(--border);
    background: var(--surface);
    color: var(--muted);
    font-size: 14px;
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    gap: 20px;
}

@media (max-width: 640px) {
    .header-inner {
        align-items: flex-start;
        flex-direction: column;
        padding: 16px 0;
        gap: 9px;
    }

    nav {
        flex-wrap: wrap;
        gap: 14px;
    }

    main {
        padding-top: 30px;
    }

    .hero,
    .content-card {
        padding: 27px 23px;
    }

    .footer-inner {
        flex-direction: column;
        gap: 5px;
    }
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #101318;
        --surface: #181c22;
        --text: #edf0f5;
        --muted: #a2abb7;
        --border: #2b313a;
        --accent: #82a0ff;
        --accent-soft: #202b4b;
        --shadow: none;
    }

    .site-header {
        background: rgba(24, 28, 34, 0.96);
    }

    .content-card p,
    .content-card li {
        color: #bcc3cd;
    }
}