/* ==========================================================================
   Personal Homepage — Minimal, Dark, Engineering-first.
   ========================================================================== */

:root {
  --bg: #0d1117;
  --bg-alt: #0a0d12;
  --bg-elev: #11161d;
  --border: #1f2630;
  --border-strong: #2a313c;
  --fg: #c9d1d9;
  --fg-dim: #8b949e;
  --fg-mute: #6e7681;
  --fg-strong: #e6edf3;
  --accent: #7ee787;
  --accent-2: #58a6ff;
  --orange: #d29922;
  --red: #ff7b72;
  --purple: #bc8cff;
  --cyan: #39c5cf;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --radius: 4px;
  --max: 1040px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: var(--accent-2);
  text-decoration: none;
}
a:hover { text-decoration: underline; }

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

/* ==========================================================================
   Top bar
   ========================================================================== */
.top-bar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(13, 17, 23, 0.85);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--border);
}
.top-bar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}
.logo {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--fg-strong);
  white-space: nowrap;
}
.logo:hover { text-decoration: none; }
.logo-prefix { color: var(--accent); }
.logo-sep { color: var(--fg-mute); }
.logo-path { color: var(--orange); }
.logo-cursor {
  color: var(--accent-2);
  margin-left: 4px;
  animation: blink 1.1s steps(1) infinite;
}
@keyframes blink {
  50% { opacity: 0.15; }
}

.nav {
  display: flex;
  gap: 4px;
}
.nav a {
  color: var(--fg-dim);
  font-size: 14px;
  padding: 6px 10px;
  border-radius: var(--radius);
}
.nav a:hover {
  color: var(--fg-strong);
  background: var(--bg-elev);
  text-decoration: none;
}

.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border-strong);
  width: 36px;
  height: 32px;
  border-radius: var(--radius);
  cursor: pointer;
  padding: 0;
  position: relative;
}
.nav-toggle span {
  display: block;
  width: 16px;
  height: 1.5px;
  background: var(--fg);
  margin: 3px auto;
  transition: transform 0.2s, opacity 0.2s;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(4.5px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-4.5px) rotate(-45deg); }

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  padding: 72px 0 56px;
  border-bottom: 1px solid var(--border);
}
.hero-kicker {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--accent);
  margin: 0 0 12px;
  letter-spacing: 0.5px;
}
.hero-title {
  font-size: clamp(22px, 3.2vw, 34px);
  font-weight: 600;
  color: var(--fg-strong);
  margin: 0 0 20px;
  line-height: 1.35;
}
.hero-sub { color: var(--fg-dim); }
.hero-sub p {
  margin: 6px 0;
  font-size: 15px;
}
.hero-actions {
  margin-top: 28px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.btn {
  display: inline-flex;
  align-items: center;
  font-family: var(--mono);
  font-size: 13px;
  padding: 8px 14px;
  border-radius: var(--radius);
  border: 1px solid var(--border-strong);
  background: var(--bg-elev);
  color: var(--fg-strong);
  transition: background 0.15s, border-color 0.15s;
}
.btn:hover {
  background: #1a212b;
  border-color: #39434f;
  text-decoration: none;
}
.btn-primary {
  border-color: #238636;
  color: var(--accent);
}
.btn-primary:hover {
  background: #238636;
  color: #0d1117;
}

/* ==========================================================================
   Sections
   ========================================================================== */
.section {
  padding: 56px 0;
  border-bottom: 1px solid var(--border);
}
.section-alt {
  background: var(--bg-alt);
}
.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 8px;
}
.section-title {
  position: relative;
  font-size: 20px;
  font-weight: 600;
  color: var(--fg-strong);
  margin: 0 0 18px;
  padding-left: 14px;
}
.section-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 3px;
  background: var(--accent);
  border-radius: 2px;
}
.muted { color: var(--fg-dim); }
.small { font-size: 13px; }

/* About */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 40px;
}
.about-main p { margin: 8px 0; }
.about-subtitle {
  font-size: 15px;
  font-weight: 600;
  color: var(--fg-strong);
  margin: 22px 0 6px;
}
.dot-list {
  list-style: none;
  padding: 0;
  margin: 12px 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 4px 24px;
}
.dot-list-sm { grid-template-columns: 1fr; margin: 8px 0; }
.dot-list-sm li {
  font-family: var(--body);
  font-size: 14px;
}
.dot-list li {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--fg);
  padding-left: 16px;
  position: relative;
}
.dot-list li::before {
  content: "–";
  position: absolute;
  left: 0;
  color: var(--fg-mute);
}
.quote {
  margin: 20px 0 0;
  padding: 14px 18px;
  border-left: 3px solid var(--accent);
  background: var(--bg-elev);
  color: var(--fg-strong);
  font-size: 14px;
  border-radius: 0 var(--radius) var(--radius) 0;
}

.side-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  font-size: 13px;
}
.side-card-title {
  color: var(--fg-strong);
  font-weight: 600;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px dashed var(--border);
}
.kv { margin: 0; }
.kv > div {
  display: flex;
  justify-content: space-between;
  padding: 5px 0;
  border-bottom: 1px dotted var(--border);
  gap: 12px;
}
.kv > div:last-child { border-bottom: none; }
.kv dt { color: var(--fg-dim); }
.kv dd { margin: 0; color: var(--fg-strong); text-align: right; font-family: var(--mono); font-size: 13px; }

/* Cards (interests) */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 14px;
}
.card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 18px 16px;
  transition: border-color 0.15s, transform 0.15s;
}
.card:hover {
  border-color: var(--border-strong);
  transform: translateY(-1px);
}
.card-head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}
.card-tag {
  font-size: 11px;
  color: var(--fg-dim);
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border);
  padding: 2px 8px;
  border-radius: 12px;
}
.card h3 {
  font-size: 15px;
  color: var(--fg-strong);
  margin: 0;
  font-weight: 600;
}
.card p {
  font-size: 14px;
  color: var(--fg-dim);
  margin: 8px 0 0;
}

/* Tags (tech stack) */
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}
.tag {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--fg);
  background: var(--bg-elev);
  border: 1px solid var(--border);
  padding: 4px 10px;
  border-radius: 999px;
  transition: background 0.15s, border-color 0.15s;
}
.tag:hover {
  border-color: var(--border-strong);
  background: #161c24;
}
.tag-sm { font-size: 11px; padding: 2px 8px; }
.tag-lang { color: var(--orange); border-color: rgba(210, 153, 34, 0.35); }
.tag-oss  { color: var(--accent); border-color: rgba(126, 231, 135, 0.35); }

/* Article list */
.article-list {
  list-style: none;
  padding: 0;
  margin: 14px 0 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.article-item {
  padding: 16px 18px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
}
.article-item:last-child { border-bottom: none; }
.article-item:hover { background: #131921; }
.article-title-row { margin-bottom: 4px; }
.article-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--accent-2);
}
.article-title:hover { text-decoration: underline; }
.article-excerpt {
  color: var(--fg-dim);
  font-size: 14px;
  margin: 4px 0 8px;
}
.article-meta {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--fg-mute);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px;
}
.dot-sep { color: var(--fg-mute); padding: 0 2px; }
.article-tags { display: inline-flex; gap: 4px; flex-wrap: wrap; }

/* Project cards */
.repo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 14px;
  margin-top: 14px;
}
.repo {
  display: block;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  color: var(--fg);
  transition: border-color 0.15s, transform 0.15s;
}
.repo:hover {
  border-color: var(--border-strong);
  transform: translateY(-1px);
  text-decoration: none;
}
.repo-head {
  margin-bottom: 8px;
}
.repo-name {
  font-family: var(--mono);
  font-size: 15px;
  font-weight: 600;
  color: var(--accent-2);
}
.repo-desc {
  color: var(--fg-dim);
  font-size: 14px;
  margin: 0 0 14px;
  min-height: 42px;
}
.repo-meta {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--fg-mute);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px;
}
.lang-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  display: inline-block;
  margin-right: 4px;
}
.lang-c   { background: #555555; }
.lang-cpp { background: #f34b7d; }
.lang-sh  { background: #89e051; }
.lang-vim { background: #199f4b; }
.lang-py  { background: #3572A5; }

/* Philosophy */
.quotes {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 12px;
  margin-top: 14px;
}
.quote-block {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent-2);
  border-radius: var(--radius);
  padding: 16px 18px;
}
.quote-block .q-num {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--fg-mute);
  display: block;
  margin-bottom: 6px;
}
.quote-block p {
  margin: 0;
  color: var(--fg-strong);
  font-size: 15px;
}

/* Contact */
.contact-icons {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 14px;
}
.contact-icon {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 18px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--fg);
  fill: var(--fg);
  font-size: 14px;
  transition: border-color 0.15s, background 0.15s, color 0.15s, transform 0.15s;
}
.contact-icon:hover {
  border-color: var(--accent);
  background: #151b23;
  color: var(--fg-strong);
  text-decoration: none;
  transform: translateY(-1px);
}
.contact-icon svg {
  flex-shrink: 0;
  color: var(--fg);
}
.contact-icon-label {
  color: var(--fg-strong);
}

.contact-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 10px;
  margin-top: 14px;
}
.contact-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 16px;
  color: var(--fg);
  font-family: var(--mono);
  font-size: 14px;
  transition: border-color 0.15s, background 0.15s;
}
.contact-item:hover {
  border-color: var(--border-strong);
  background: #151b23;
  text-decoration: none;
}
.contact-label { color: var(--fg-dim); }
.contact-value { color: var(--fg-strong); }

/* Footer */
.foot {
  padding: 24px 0 40px;
  background: var(--bg-alt);
}
.foot-inner {
  display: flex;
  flex-direction: column;
  gap: 4px;
  font-size: 13px;
  color: var(--fg-mute);
}
.foot-inner .foot-copy:first-child {
  color: var(--accent);
  font-family: var(--mono);
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 780px) {
  .nav {
    display: none;
    position: absolute;
    top: 56px;
    right: 16px;
    left: 16px;
    flex-direction: column;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 8px;
    gap: 2px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.35);
  }
  .nav.open { display: flex; }
  .nav a {
    padding: 10px 12px;
    border-radius: 3px;
  }
  .nav-toggle { display: block; }

  .hero { padding: 48px 0 40px; }
  .section { padding: 44px 0; }

  .about-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  .dot-list {
    grid-template-columns: 1fr;
  }

  .section-head { flex-direction: column; align-items: flex-start; gap: 4px; }
}

@media (max-width: 480px) {
  .hero-title { font-size: 22px; }
  .logo-path { display: none; }
}