:root {
    --primary: #0891b2;
    --primary-dark: #0e7490;
    --bg: #f9fafb;
    --card: #ffffff;
    --text: #111827;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --border: #e5e7eb;
    --radius: 12px;
    --radius-sm: 8px;
    --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }

.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

/* Header */
header.site-header {
    background: var(--card);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 10;
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
}

.logo { font-size: 22px; font-weight: 800; letter-spacing: -0.5px; }
.logo a { color: var(--text); }
.logo span { color: var(--primary); }

nav { display: flex; gap: 24px; }
nav a { font-size: 14px; font-weight: 500; color: var(--text-secondary); }
nav a:hover { color: var(--primary); }
nav a.active { color: var(--primary); }

/* Hero */
.hero {
    padding: 80px 0;
    text-align: center;
    background: var(--card);
    border-bottom: 1px solid var(--border);
}

.hero h1 {
    font-size: 44px;
    font-weight: 800;
    letter-spacing: -1px;
    margin-bottom: 16px;
}

.hero p { font-size: 18px; color: var(--text-secondary); margin-bottom: 32px; }

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 15px;
    transition: all 0.2s;
}

.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); color: #fff; }

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

/* Sections */
.section { padding: 56px 0; }
.section-alt { background: var(--card); }

.section-title {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
    text-align: center;
}

.section-desc {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 40px;
}

.section-head-center { text-align: center; margin-bottom: 40px; }
.section-head-center h2 { font-size: 28px; font-weight: 700; margin-bottom: 8px; }
.section-head-center p { color: var(--text-secondary); }

/* Page header */
.page-header {
    padding: 60px 0;
    text-align: center;
    background: var(--card);
    border-bottom: 1px solid var(--border);
}

.page-header h1 { font-size: 40px; font-weight: 800; letter-spacing: -1px; margin-bottom: 12px; }
.page-header p { font-size: 18px; color: var(--text-secondary); }

/* Grids */
.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }

@media (max-width: 800px) { .grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .grid { grid-template-columns: 1fr; } }

.method-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
@media (max-width: 800px) { .method-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .method-grid { grid-template-columns: 1fr; } }

/* Cards */
.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    transition: all 0.2s;
}

.card:hover {
    border-color: var(--primary);
    box-shadow: 0 4px 12px rgba(8, 145, 178, 0.1);
}

.card h3 { font-size: 16px; font-weight: 600; margin-bottom: 8px; }
.card h3 a { color: var(--text); }
.card h3 a:hover { color: var(--primary); }

.card p { font-size: 14px; color: var(--text-secondary); margin-bottom: 12px; line-height: 1.7; }

.card-meta { font-size: 12px; color: var(--text-muted); }

.method-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 20px;
    font-size: 14px;
}

.method-card h3 { font-size: 15px; font-weight: 600; margin-bottom: 6px; }
.method-card p { font-size: 13px; color: var(--text-secondary); }

/* Tags */
.tag {
    display: inline-block;
    padding: 3px 8px;
    font-size: 11px;
    font-weight: 500;
    border-radius: 4px;
    background: #f0f9ff;
    color: var(--primary-dark);
    margin-right: 6px;
}

/* News list */
.news-list { max-width: 860px; margin: 0 auto; }

.news-item {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 20px;
    transition: all 0.2s;
}

.news-item:hover {
    border-color: var(--primary);
    box-shadow: 0 4px 12px rgba(8, 145, 178, 0.1);
}

.news-date { font-size: 12px; color: var(--text-muted); margin-bottom: 6px; }

.news-item h3 { font-size: 17px; font-weight: 600; margin-bottom: 10px; }
.news-item h3 a { color: var(--text); }
.news-item h3 a:hover { color: var(--primary); }

.news-item p { font-size: 14px; color: var(--text-secondary); margin-bottom: 10px; line-height: 1.7; }

.news-source { font-size: 12px; color: var(--text-secondary); }

/* Article */
.article-header {
    padding: 48px 0 32px;
    background: var(--card);
    border-bottom: 1px solid var(--border);
}

.article-header h1 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 12px;
    line-height: 1.3;
}

.article-meta { font-size: 14px; color: var(--text-secondary); }

.article { max-width: 800px; margin: 0 auto; padding: 40px 20px; }

.article h2 {
    font-size: 20px;
    font-weight: 600;
    margin: 32px 0 16px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
}

.article h2:first-child { margin-top: 0; padding-top: 0; border-top: none; }

.article h3 { font-size: 17px; font-weight: 600; margin: 24px 0 12px; }

.article p { margin-bottom: 16px; color: var(--text-secondary); }
.article strong { color: var(--text); }

.article ul, .article ol { margin: 16px 0; padding-left: 24px; color: var(--text-secondary); }
.article li { margin-bottom: 8px; }
.article li strong { color: var(--text); }

.article blockquote {
    margin: 24px 0;
    padding: 20px;
    background: #f0f9ff;
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--primary);
    color: var(--primary-dark);
    font-size: 16px;
}

.article blockquote strong { display: block; margin-top: 8px; font-size: 14px; font-weight: 400; color: var(--text-secondary); }

.article table {
    width: 100%;
    border-collapse: collapse;
    margin: 16px 0 24px;
    font-size: 14px;
    color: var(--text-secondary);
}

.article th, .article td {
    border: 1px solid var(--border);
    padding: 10px 14px;
    text-align: left;
}

.article th { background: #f0f9ff; color: var(--primary-dark); font-weight: 600; }
.article tr:nth-child(even) td { background: #fafafa; }

/* Design system steps */
.step-wrap { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.step {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--primary);
    color: #fff;
    font-size: 13px;
    font-weight: 600;
    flex-shrink: 0;
}

/* B/C compare */
.compare { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 16px 0 24px; }

@media (max-width: 560px) { .compare { grid-template-columns: 1fr; } }

.compare-box {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
}

.compare-box h3 { font-size: 15px; font-weight: 600; margin-bottom: 10px; }
.compare-box ul { margin: 0; padding-left: 20px; color: var(--text-secondary); }
.compare-box li { margin-bottom: 6px; font-size: 14px; }

.compare-box.tob { border-top: 3px solid var(--primary); }
.compare-box.toc { border-top: 3px solid #f59e0b; }

/* Sprint days */
.day {
    display: inline-block;
    padding: 2px 8px;
    margin-right: 6px;
    border-radius: 4px;
    background: #f0f9ff;
    color: var(--primary-dark);
    font-size: 13px;
    font-weight: 600;
}

/* Check list */
.check { color: var(--primary); font-weight: 700; margin-right: 4px; }

/* News single */
.news-article { max-width: 720px; margin: 0 auto; padding: 40px 20px; }
.news-article p { margin-bottom: 16px; color: var(--text-secondary); font-size: 16px; line-height: 1.8; }
.news-actions { margin-top: 32px; text-align: center; }

/* About */
.content { max-width: 680px; margin: 0 auto; }

.about-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
}

.about-card p { font-size: 17px; color: var(--text-secondary); margin-bottom: 20px; }

.about-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 16px; color: var(--text); }

.about-card ul { list-style: none; }
.about-card li {
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 12px;
}
.about-card li:last-child { border-bottom: none; }

.about-card .icon {
    width: 32px;
    height: 32px;
    background: #f0f9ff;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
}

.quote {
    margin-top: 24px;
    padding: 20px;
    background: #f0f9ff;
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--primary);
}

.quote p { font-size: 18px; color: var(--primary-dark); margin: 0; }
.quote strong { display: block; margin-top: 8px; font-size: 14px; font-weight: 400; color: var(--text-secondary); }

.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin-top: 40px; }
@media (max-width: 560px) { .stats { grid-template-columns: 1fr; } }

.stat {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    text-align: center;
}

.stat-num { font-size: 36px; font-weight: 700; color: var(--primary); }
.stat-label { font-size: 14px; color: var(--text-secondary); }

/* Footer */
footer.site-footer {
    padding: 40px 0;
    text-align: center;
    background: var(--card);
    border-top: 1px solid var(--border);
}

footer.site-footer .logo { margin-bottom: 8px; }
footer.site-footer p { font-size: 14px; color: var(--text-secondary); margin-bottom: 16px; }
footer.site-footer .copy { font-size: 12px; color: var(--text-muted); }
footer.site-footer .copy a { color: var(--text-muted); }