:root {
  --bg: #0f1419;
  --surface: #171d26;
  --surface-2: #1e2631;
  --text: #e6edf3;
  --muted: #9aa7b4;
  --accent: #e86736;
  --accent-2: #4fc3f7;
  --border: #26303d;
  --radius: 14px;
  --max: 900px;
  --shadow: 0 10px 30px rgba(0,0,0,.35);
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f6f7f9;
    --surface: #ffffff;
    --surface-2: #f0f2f5;
    --text: #1a222b;
    --muted: #5b6672;
    --border: #e2e6ea;
    --shadow: 0 10px 30px rgba(20,40,70,.10);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Segoe UI Symbol", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.container { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* Top bar */
.topbar {
  position: sticky; top: 0; z-index: 20;
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.topbar__inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-weight: 700; }
.brand__mark { font-size: 22px; }
.brand__name { letter-spacing: .3px; }

.nav { display: flex; align-items: center; gap: 22px; }
.nav a { color: var(--muted); text-decoration: none; font-weight: 500; font-size: 15px; transition: color .2s; }
.nav a:hover { color: var(--accent); }
.lang {
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  border-radius: 999px;
  padding: 6px 14px;
  font-weight: 700;
  cursor: pointer;
  font-size: 13px;
  transition: transform .15s, border-color .2s;
}
.lang:hover { border-color: var(--accent); transform: translateY(-1px); }

.hamburger { display: none; background: none; border: none; color: var(--text); font-size: 26px; cursor: pointer; }

/* Hero */
.hero { padding: 72px 20px 40px; }
.hero h1 { font-size: clamp(28px, 5vw, 44px); line-height: 1.15; margin: 0 0 16px; letter-spacing: -.5px; }
.lede { font-size: 18px; color: var(--muted); max-width: 680px; margin: 0 0 24px; }
.hero__tags { display: flex; flex-wrap: wrap; gap: 10px; }
.tag {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--accent-2);
  padding: 6px 14px; border-radius: 999px; font-size: 13px; font-weight: 600;
}

/* Blocks & cards */
.block { padding: 24px 20px 40px; }
.section-title { font-size: 22px; margin: 0 0 20px; border-left: 3px solid var(--accent); padding-left: 12px; }
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 24px;
  margin-bottom: 18px;
  box-shadow: var(--shadow);
  transition: transform .18s, border-color .2s;
}
.card:hover { transform: translateY(-3px); border-color: color-mix(in srgb, var(--accent) 55%, transparent); }
.card h3 { margin: 0 0 10px; font-size: 20px; }
.card p { margin: 0; color: var(--muted); }
code {
  background: var(--surface-2);
  padding: 2px 7px; border-radius: 6px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 13px; color: var(--accent-2);
}

.footer-note { border-top: 1px solid var(--border); }
.footer-note p { color: var(--muted); font-size: 14px; }

/* Footer */
.foot { border-top: 1px solid var(--border); margin-top: 30px; }
.foot__inner { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; padding: 22px 20px; color: var(--muted); font-size: 14px; }
.foot__link a { color: var(--muted); }
.foot__link a:hover { color: var(--accent); }

/* Mobile nav */
@media (max-width: 720px) {
  .hamburger { display: block; }
  .nav {
    position: absolute; top: 60px; right: 0; left: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 8px 20px 16px;
    max-height: 0; overflow: hidden; transition: max-height .25s;
  }
  .nav.open { max-height: 320px; }
  .nav a { padding: 13px 0; border-bottom: 1px solid var(--border); }
  .nav .lang { margin-top: 12px; text-align: center; }
}

/* ---- Article / blog layouts ---- */
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

.cover {
  background: radial-gradient(1200px 400px at 20% -10%, color-mix(in srgb, var(--accent) 22%, transparent), transparent 60%),
              radial-gradient(900px 400px at 100% 0%, color-mix(in srgb, var(--accent-2) 16%, transparent), transparent 55%);
  padding: 56px 20px 32px;
  border-bottom: 1px solid var(--border);
}
.cover__kicker { color: var(--accent); font-weight: 700; letter-spacing: 1px; text-transform: uppercase; font-size: 12px; }
.cover h1 { font-size: clamp(30px, 5vw, 46px); line-height: 1.1; margin: 10px 0 12px; letter-spacing: -.6px; }
.cover__meta { color: var(--muted); font-size: 14px; display: flex; flex-wrap: wrap; gap: 14px; }
.cover__meta span { display: inline-flex; align-items: center; gap: 6px; }
.lede-lg { font-size: 20px; color: var(--muted); max-width: 720px; margin: 18px 0 0; }

.article { padding: 44px 20px 60px; }
.article h2 { font-size: 25px; margin: 40px 0 12px; letter-spacing: -.3px; }
.article h3 { font-size: 20px; margin: 28px 0 10px; }
.article p { margin: 0 0 16px; }
.article ul, .article ol { color: var(--text); padding-left: 22px; }
.article li { margin: 6px 0; }
.article blockquote {
  margin: 22px 0; padding: 12px 18px;
  border-left: 3px solid var(--accent);
  background: var(--surface-2); border-radius: 0 10px 10px 0; color: var(--text);
  font-style: italic;
}
.article code { font-size: 13px; }
.article pre {
  background: #0b0f14; border: 1px solid var(--border);
  border-radius: 12px; padding: 16px 18px; overflow-x: auto;
  font-size: 13.5px; line-height: 1.55; color: #d7e0ea;
}
.article pre code { background: none; padding: 0; color: inherit; }
.article .callout {
  border: 1px solid var(--border); border-left: 3px solid var(--accent-2);
  border-radius: 12px; padding: 14px 18px; margin: 22px 0; background: var(--surface);
}
.article .callout b { color: var(--accent-2); }
.article table { border-collapse: collapse; width: 100%; margin: 20px 0; font-size: 14px; }
.article th, .article td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; }
.article th { background: var(--surface-2); }
.article a { color: var(--accent); }

/* Home / article grid */
.grid { padding: 34px 20px 50px; }
.grid__head { padding: 40px 20px 8px; }
.grid__head h1 { font-size: 30px; margin: 0 0 6px; }
.grid__head p { color: var(--muted); margin: 0; }
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; }
.post-card {
  display: flex; flex-direction: column; gap: 8px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px; text-decoration: none; color: var(--text);
  transition: transform .18s, border-color .2s;
}
.post-card:hover { transform: translateY(-3px); border-color: color-mix(in srgb, var(--accent) 55%, transparent); }
.post-card .cat { color: var(--accent); font-size: 12px; font-weight: 700; letter-spacing: .6px; text-transform: uppercase; }
.post-card h3 { margin: 0; font-size: 18px; line-height: 1.3; }
.post-card .ex { color: var(--muted); font-size: 14px; margin: 0; }
.post-card .foot { color: var(--muted); font-size: 12px; margin-top: auto; padding-top: 8px; }

.toc {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 12px; padding: 16px 20px; margin: 0 0 26px;
}
.toc b { display: block; margin-bottom: 8px; }
.toc ol { padding-left: 20px; margin: 0; columns: 2; gap: 30px; }
@media (max-width: 640px) { .toc ol { columns: 1; } }
.toc a { color: var(--muted); text-decoration: none; font-size: 14px; }
.toc a:hover { color: var(--accent); }

/* Search */
.searchbox { padding: 20px; }
.searchbox input {
  width: 100%; padding: 12px 16px; font-size: 15px;
  background: var(--surface-2); color: var(--text);
  border: 1px solid var(--border); border-radius: 12px; outline: none;
}
.searchbox input:focus { border-color: var(--accent); }
.post-card.hidden { display: none; }

.login-btn {
  background: var(--accent) !important;
  color: #fff !important;
  border-color: transparent !important;
  font-weight: 700;
}
.login-btn:hover { filter: brightness(1.08); transform: translateY(-1px); }