/* ===== Bauhaus x AI ===== */
@import url('variables.css');

:root {
    --bg: var(--void);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
    font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    color: var(--text); background: var(--bg); line-height: 1.6;
    padding-top: var(--nav-height); -webkit-font-smoothing: antialiased;
}

a { color: var(--blue); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--purple); }

/* Geometric BG */
body::before {
    content: ''; position: fixed; top: -180px; right: -120px;
    width: 420px; height: 420px; border: 2px solid rgba(37,99,235,0.06);
    border-radius: 50%; pointer-events: none; z-index: 0;
}
body::after {
    content: ''; position: fixed; bottom: -100px; left: -80px;
    width: 280px; height: 280px; background: rgba(124,58,237,0.03);
    pointer-events: none; z-index: 0;
}

/* Nav */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; height: var(--nav-height);
    background: rgba(255,255,255,0.92); backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px); border-bottom: 1px solid var(--border); z-index: 1000;
}
.nav-container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; display: flex; align-items: center; height: 100%; }
.nav-brand {
    font-weight: 700; font-size: 1.3rem; letter-spacing: -0.3px;
    background: linear-gradient(135deg, var(--blue), var(--purple));
    -webkit-background-clip: text; background-clip: text; color: transparent;
}
.nav-brand:hover { opacity: 0.8; }
.nav-links { display: flex; gap: 2rem; margin-left: auto; list-style: none; }
.nav-link { color: var(--text); font-size: 0.9rem; font-weight: 500; transition: color 0.2s; }
.nav-link:hover, .nav-link.active { color: var(--blue); }

.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 4px; }
.hamburger, .hamburger::before, .hamburger::after { display: block; width: 22px; height: 2px; background: var(--text); transition: transform 0.3s, opacity 0.3s; border-radius: 1px; }
.hamburger { position: relative; }
.hamburger::before, .hamburger::after { content: ''; position: absolute; left: 0; }
.hamburger::before { top: -6px; } .hamburger::after { top: 6px; }

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }

/* Hero */
.hero { padding: 3rem 2rem; margin: 2rem 0; text-align: center; background: linear-gradient(145deg, #ffffff 0%, #f3f4f6 100%); border-radius: 2rem; box-shadow: 0 8px 20px rgba(0,0,0,0.02); position: relative; z-index: 1; }
.hero-content { max-width: 640px; margin: 0 auto; }
.hero-badge { display: inline-block; padding: 0.2rem 0.8rem; background: #eef2ff; color: var(--blue); font-size: 0.75rem; font-weight: 600; border-radius: 30px; text-transform: uppercase; margin-bottom: 1rem; letter-spacing: 0; }
.hero-title { font-size: 2.8rem; font-weight: 800; line-height: 1.15; letter-spacing: -0.03em; margin-bottom: 1rem; }
.hero-title .highlight { background: linear-gradient(135deg, var(--purple), var(--blue)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero-subtitle { font-size: 1.05rem; color: var(--sub); line-height: 1.7; margin-bottom: 1.2rem; }
.hero-tags { display: flex; gap: 8px; flex-wrap: wrap; justify-content: center; }
.hero-tag { padding: 0.2rem 0.7rem; background: var(--tag-bg); border-radius: 20px; font-size: 0.7rem; color: #1e293b; font-weight: 400; }

/* Section heading */
.section-heading { font-size: 2rem; font-weight: 700; letter-spacing: -0.02em; margin-bottom: 2rem; border-left: 5px solid var(--blue); padding-left: 1rem; }

/* Post grid */
.posts-section { padding: 24px 0 80px; position: relative; z-index: 1; }
.posts-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 20px; }
.post-card { background: var(--surface); border: 1px solid #edf2f7; border-radius: 1.5rem; padding: 1.5rem; transition: all 0.2s ease; display: flex; flex-direction: column; box-shadow: 0 4px 12px rgba(0,0,0,0.04); }
.post-card:hover { border-color: #cbd5e1; transform: translateY(-4px); box-shadow: 0 20px 30px -12px rgba(0,0,0,0.1); }
.post-card .post-date { font-size: 0.8rem; color: var(--muted); font-weight: 500; letter-spacing: 0.04em; margin-bottom: 10px; }
.post-card .post-title { font-size: 1.2rem; font-weight: 700; line-height: 1.35; margin-bottom: 8px; letter-spacing: -0.01em; }
.post-card .post-title a { color: var(--text); }
.post-card .post-title a:hover { color: var(--blue); }
.post-card .post-summary { font-size: 0.9rem; color: var(--sub); line-height: 1.6; flex: 1; margin-bottom: 14px; }
.post-card .read-more { font-size: 0.85rem; font-weight: 600; color: var(--blue); display: inline-flex; align-items: center; gap: 4px; letter-spacing: 0.03em; transition: gap 0.2s; }
.post-card .read-more:hover { gap: 8px; color: var(--purple); }
.no-posts { color: var(--sub); font-size: 1.1rem; text-align: center; padding: 80px 0; grid-column: 1 / -1; }

/* Article */
.post-full { max-width: var(--max-width-content); margin: 0 auto; padding: 48px 0 80px; position: relative; z-index: 1; }
.post-header { margin-bottom: 40px; padding: 2rem; background: var(--surface); border-radius: 1.5rem; box-shadow: 0 4px 12px rgba(0,0,0,0.04); border: 1px solid #edf2f7; }
.post-header .post-title { font-size: 2rem; font-weight: 800; line-height: 1.15; letter-spacing: -0.02em; margin-bottom: 10px; }
.post-header .post-date { font-size: 0.85rem; color: var(--muted); font-weight: 500; letter-spacing: 0.05em; }
.post-body { font-size: 1.05rem; line-height: 1.85; color: #374151; background: var(--surface); border-radius: 1.5rem; padding: 2rem; box-shadow: 0 4px 12px rgba(0,0,0,0.04); border: 1px solid #edf2f7; }
.post-body h2 { font-size: 1.5rem; font-weight: 700; color: var(--text); margin: 36px 0 14px; letter-spacing: -0.02em; border-left: 4px solid var(--blue); padding-left: 1rem; }
.post-body h3 { font-size: 1.2rem; font-weight: 700; color: var(--text); margin: 32px 0 10px; letter-spacing: -0.01em; }
.post-body p { margin-bottom: 18px; }
.post-body ul, .post-body ol { margin-bottom: 18px; padding-left: 24px; }
.post-body li { margin-bottom: 6px; }
.post-body li::marker { color: var(--blue); }
.post-body strong { font-weight: 600; color: var(--text); }
.post-body a { color: var(--blue); text-decoration: underline; text-underline-offset: 3px; }
.post-body a:hover { color: var(--purple); }
.post-body img { max-width: 100%; height: auto; display: block; margin: 1.5rem auto; border-radius: 0.5rem; }
.post-body table { width: 100%; border-collapse: collapse; margin: 1.25rem 0; font-size: 0.92rem; }
.post-body th { background: #f1f5f9; color: #1e293b; font-weight: 600; padding: 0.6rem 0.8rem; border: 1px solid #d1d5db; text-align: left; font-size: 0.85rem; letter-spacing: 0.02em; }
.post-body td { padding: 0.5rem 0.8rem; border: 1px solid #e5e7eb; color: #374151; line-height: 1.55; }
.post-body tr:nth-child(even) td { background: #f9fafb; }
.post-body code { background: var(--code-bg); padding: 2px 7px; font-family: 'JetBrains Mono','Fira Code',Consolas,monospace; font-size: 0.88em; color: #1e293b; }
.post-body pre { background: var(--code-bg); padding: 20px 24px; overflow-x: auto; margin-bottom: 22px; border: 1px solid var(--border); border-left: 4px solid var(--blue); }
.post-body pre code { background: none; padding: 0; font-size: 0.84em; line-height: 1.7; }
.post-body blockquote { border-left: 3px solid var(--gold); padding: 4px 0 4px 18px; margin: 20px 0; color: var(--sub); font-style: italic; background: rgba(217,119,6,0.03); }
.back-link { display: inline-flex; align-items: center; gap: 6px; margin-top: 48px; font-size: 0.85rem; font-weight: 600; color: var(--sub); letter-spacing: 0.03em; transition: color 0.2s, gap 0.2s; padding: 10px 0; border-top: 1px solid var(--border); width: 100%; }
.back-link:hover { color: var(--blue); gap: 10px; }

/* About */
.about-page { max-width: var(--max-width-content); margin: 0 auto; padding: 48px 0 80px; position: relative; z-index: 1; }
.about-page .page-title { font-size: 2.2rem; font-weight: 700; letter-spacing: -0.02em; margin-bottom: 2rem; border-left: 5px solid var(--blue); padding-left: 1rem; }
.about-content { font-size: 1.05rem; line-height: 1.85; color: #374151; background: var(--surface); border-radius: 1.5rem; padding: 2rem; box-shadow: 0 4px 12px rgba(0,0,0,0.04); border: 1px solid #edf2f7; }
.about-content p { margin-bottom: 16px; }

.contact-box { background: white; border-radius: 1.5rem; padding: 1.5rem 2rem; border: 1px solid #edf2f7; margin-top: 1.5rem; }
.contact-box h3 { font-size: 1rem; font-weight: 700; margin-bottom: 1rem; letter-spacing: 0.04em; text-transform: uppercase; color: #6c757d; }
.contact-bar { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.contact-item { display: flex; align-items: center; gap: 0.6rem; padding: 0.6rem 0.9rem; background: #f9fafb; border-radius: 0.75rem; text-decoration: none; color: inherit; }
.contact-icon { width: 28px; height: 28px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 0.75rem; flex-shrink: 0; }
.contact-icon.email { background: #eef2ff; color: var(--blue); }
.contact-icon.qq { background: #12B7F5; }
.contact-icon.wechat { background: #07C160; }
.contact-label { font-size: 0.7rem; color: #9ca3af; text-transform: uppercase; letter-spacing: 0.05em; width: 28px; flex-shrink: 0; }
.contact-value { font-size: 0.85rem; color: #1f2937; font-weight: 500; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

/* 404 */
.error-page { text-align: center; padding: 100px 0; position: relative; z-index: 1; }
.error-code { font-size: 8rem; font-weight: 800; line-height: 1; background: linear-gradient(135deg, var(--blue), var(--purple)); -webkit-background-clip: text; background-clip: text; color: transparent; margin-bottom: 12px; letter-spacing: -0.04em; }
.error-message { font-size: 1.1rem; color: var(--sub); margin-bottom: 32px; }
.error-page .back-link { justify-content: center; border: none; padding: 0; color: var(--blue); font-size: 0.9rem; }

/* Footer */
.footer { text-align: center; padding: 24px; color: var(--muted); font-size: 0.8rem; border-top: 1px solid var(--border); position: relative; z-index: 1; }
.footer a { color: var(--blue); }

/* Responsive */
@media (max-width: 768px) {
    .hero { grid-template-columns: 1fr; text-align: left; padding: 40px 0; gap: 24px; }
    .hero-visual { display: none; }
    .hero-title { font-size: 2rem; }
    .posts-grid { grid-template-columns: 1fr; }
    .post-header .post-title { font-size: 1.7rem; }
    .section-heading { font-size: 1.3rem; }
    .about-page .page-title { font-size: 1.7rem; }
}
@media (max-width: 600px) {
    .nav-toggle { display: block; }
    .nav-links { display: none; position: absolute; top: var(--nav-height); left: 0; right: 0; background: rgba(255,255,255,0.96); backdrop-filter: blur(12px); flex-direction: column; gap: 0; border-bottom: 1px solid var(--border); }
    .nav-links.open { display: flex; }
    .nav-link { padding: 15px 24px; border-top: 1px solid var(--border); }
    .hero-title { font-size: 1.7rem; }
    .post-body { font-size: 0.98rem; }
    .error-code { font-size: 5rem; }
}
@media (max-width: 400px) {
    .hero-title { font-size: 1.45rem; }
    .hero-subtitle { font-size: 0.92rem; }
}

/* ====== Theme Toggle ====== */
.theme-toggle { background: none; border: none; cursor: pointer; font-size: 1.1rem; padding: 0.3rem; line-height: 1; opacity: 0.7; transition: opacity 0.2s; }
.theme-toggle:hover { opacity: 1; }

/* ====== Dark Mode (manual toggle + system preference) ====== */
.dark-mode,
.dark-mode :root { --void: #0d0d0d; --surface: #1a1a1a; --card: #222222; --text: #e5e5e5; --sub: #9ca3af; --muted: #6c757d; --border: #333333; --code-bg: #111111; }
.dark-mode { background: #0d0d0d; color: #e5e5e5; }
.dark-mode .navbar { background: rgba(13,13,13,0.92); border-bottom-color: #333; }
.dark-mode .nav-brand { color: #e5e5e5; }
.dark-mode .nav-link { color: #9ca3af; }
.dark-mode .nav-link:hover { color: #e5e5e5; }
.dark-mode .nav-links { background: rgba(13,13,13,0.96); border-bottom-color: #333; }
.dark-mode .nav-toggle .hamburger { background: #e5e5e5; }
.dark-mode .section-title { color: #e5e5e5; }
.dark-mode .card { background: #222; border-color: #333; }
.dark-mode .card h3 { color: #e5e5e5; }
.dark-mode .card p { color: #9ca3af; }
.dark-mode .card .meta { color: #6c757d; }
.dark-mode .card-badge { background: rgba(37,99,235,0.2); color: #93c5fd; }
.dark-mode .card-badge.green { background: rgba(5,150,105,0.2); color: #6ee7b7; }
.dark-mode .card-badge.purple { background: rgba(124,58,237,0.2); color: #c4b5fd; }
.dark-mode .card-badge.gold { background: rgba(217,119,6,0.2); color: #fcd34d; }
.dark-mode .post-body { color: #d1d5db; }
.dark-mode .post-body code { background: #111; color: #d1d5db; }
.dark-mode .post-body pre { background: #111; border-color: #333; }
.dark-mode .post-body pre code { background: transparent; }
.dark-mode .post-body blockquote { border-left-color: var(--purple); color: #9ca3af; }
.dark-mode .post-body table th { background: #1a1a1a; }
.dark-mode .post-body table td, .dark-mode .post-body table th { border-color: #333; }
.dark-mode .about-content { color: #d1d5db; }
.dark-mode .info-box { background: #222; border-color: #333; }
.dark-mode .tech-list li { color: #d1d5db; }
.dark-mode .contact-box { background: #222; border-color: #333; }
.dark-mode .contact-item { background: #1a1a1a; color: #e5e5e5; }
.dark-mode .contact-value { color: #e5e5e5; }
.dark-mode .footer { border-top-color: #333; }
.dark-mode .footer a { color: #93c5fd; }
.dark-mode .hero { background: linear-gradient(145deg, #0d0d0d 0%, #1a1a1a 100%); }
.dark-mode .hero .tagline { color: #93c5fd; }
.dark-mode .hero .bio { color: #9ca3af; }

@media (prefers-color-scheme: dark) {
  :root:not(.light-mode) { --void: #0d0d0d; --surface: #1a1a1a; --card: #222222; --text: #e5e5e5; --sub: #9ca3af; --muted: #6c757d; --border: #333333; --code-bg: #111111; }
  body:not(.light-mode) { background: #0d0d0d; color: #e5e5e5; }
  body:not(.light-mode) .navbar { background: rgba(13,13,13,0.92); border-bottom-color: #333; }
  body:not(.light-mode) .nav-brand { color: #e5e5e5; }
  body:not(.light-mode) .nav-link { color: #9ca3af; }
  body:not(.light-mode) .nav-link:hover { color: #e5e5e5; }
  body:not(.light-mode) .nav-links { background: rgba(13,13,13,0.96); border-bottom-color: #333; }
  body:not(.light-mode) .nav-toggle .hamburger { background: #e5e5e5; }
  body:not(.light-mode) .section-title { color: #e5e5e5; }
  body:not(.light-mode) .card { background: #222; border-color: #333; }
  body:not(.light-mode) .card h3 { color: #e5e5e5; }
  body:not(.light-mode) .card p { color: #9ca3af; }
  body:not(.light-mode) .card .meta { color: #6c757d; }
  body:not(.light-mode) .post-body { color: #d1d5db; }
  body:not(.light-mode) .post-body code { background: #111; color: #d1d5db; }
  body:not(.light-mode) .post-body pre { background: #111; border-color: #333; }
  body:not(.light-mode) .about-content { color: #d1d5db; }
  body:not(.light-mode) .info-box { background: #222; border-color: #333; }
  body:not(.light-mode) .contact-box { background: #222; border-color: #333; }
  body:not(.light-mode) .contact-item { background: #1a1a1a; }
  body:not(.light-mode) .footer { border-top-color: #333; }
  body:not(.light-mode) .hero { background: linear-gradient(145deg, #0d0d0d 0%, #1a1a1a 100%); }
}