:root {
  --bg: #ffffff;
  --bg-soft: #f3f6fb;
  --surface: #ffffff;
  --text: #14213d;
  --text-soft: #475569;
  --border: #e2e8f0;
  --accent: #2563eb;
  --accent-2: #0ea5e9;
  --accent-soft: #dbeafe;
  --shadow: 0 10px 30px rgba(20, 33, 61, .08);
  --radius: 14px;
  --maxw: 1100px;
  --header-h: 68px;
}
html[data-theme="dark"] {
  --bg: #0b1220;
  --bg-soft: #0f172a;
  --surface: #111c30;
  --text: #e6edf6;
  --text-soft: #9fb0c3;
  --border: #1f2c44;
  --accent: #38bdf8;
  --accent-2: #22d3ee;
  --accent-soft: #0b2f4a;
  --shadow: 0 10px 30px rgba(0, 0, 0, .45);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  transition: background .3s ease, color .3s ease;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }
.container { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50;
  height: var(--header-h);
  display: flex; align-items: center;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner { width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { font-weight: 800; font-size: 1.15rem; letter-spacing: .3px; color: var(--text); display: flex; align-items: center; gap: 8px; }
.brand .dot { width: 11px; height: 11px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft); }
.nav { display: flex; align-items: center; gap: 22px; }
.nav a { color: var(--text-soft); font-weight: 600; font-size: .95rem; }
.nav a:hover, .nav a.active { color: var(--accent); text-decoration: none; }
.header-actions { display: flex; align-items: center; gap: 10px; }
.icon-btn { background: var(--bg-soft); border: 1px solid var(--border); color: var(--text); width: 40px; height: 40px; border-radius: 10px; cursor: pointer; font-size: 1rem; display: grid; place-items: center; }
.icon-btn:hover { border-color: var(--accent); }
.lang-switch { font-size: .82rem; font-weight: 700; padding: 0 10px; }
.menu-toggle { display: none; }

/* Hero slider */
.hero { position: relative; overflow: hidden; }
.slides { position: relative; min-height: 460px; }
.slide {
  position: absolute; inset: 0; opacity: 0; transition: opacity .7s ease;
  display: flex; align-items: center;
  background: linear-gradient(135deg, var(--accent-soft), var(--bg-soft));
}
.slide.active { opacity: 1; }
.slide-inner { max-width: 760px; padding: 60px 0; }
.slide .eyebrow { font-weight: 700; letter-spacing: 2px; text-transform: uppercase; font-size: .8rem; color: var(--accent); }
.slide h1 { font-size: clamp(2rem, 5vw, 3.2rem); margin: .4em 0 .3em; line-height: 1.1; }
.slide p { font-size: 1.15rem; color: var(--text-soft); margin-bottom: 1.4em; }
.slide .cta { display: flex; gap: 12px; flex-wrap: wrap; }
.hero-dots { position: absolute; bottom: 22px; left: 50%; transform: translateX(-50%); display: flex; gap: 8px; }
.hero-dots button { width: 10px; height: 10px; border-radius: 50%; border: none; background: var(--border); cursor: pointer; }
.hero-dots button.active { background: var(--accent); }
.hero-arrows button { position: absolute; top: 50%; transform: translateY(-50%); background: var(--surface); border: 1px solid var(--border); color: var(--text); width: 44px; height: 44px; border-radius: 50%; cursor: pointer; font-size: 1.2rem; box-shadow: var(--shadow); }
.hero-arrows .prev { left: 16px; } .hero-arrows .next { right: 16px; }

/* Buttons */
.btn { display: inline-block; padding: 12px 22px; border-radius: 10px; font-weight: 700; border: 1px solid transparent; cursor: pointer; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-2); text-decoration: none; }
.btn-ghost { background: transparent; border-color: var(--border); color: var(--text); }
.btn-ghost:hover { border-color: var(--accent); text-decoration: none; }

/* Sections */
.section { padding: 70px 0; }
.section-title { font-size: 1.9rem; margin: 0 0 6px; }
.section-sub { color: var(--text-soft); margin: 0 0 34px; }
.grid { display: grid; gap: 22px; }
.cards-3 { grid-template-columns: repeat(3, 1fr); }
.cards-2 { grid-template-columns: repeat(2, 1fr); }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow); }
.card h3 { margin-top: 0; }
.card .tag { display: inline-block; font-size: .72rem; font-weight: 700; letter-spacing: .5px; text-transform: uppercase; color: var(--accent); background: var(--accent-soft); padding: 4px 10px; border-radius: 999px; margin-bottom: 12px; }

/* Blog list */
.post-list { display: grid; gap: 24px; }
.post-card { display: grid; grid-template-columns: 240px 1fr; gap: 22px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.post-thumb { background: linear-gradient(135deg, var(--accent), var(--accent-2)); min-height: 180px; display: grid; place-items: center; color: #fff; font-size: 2.4rem; font-weight: 800; }
.post-body { padding: 22px 24px 22px 0; }
.post-body h3 { margin: 0 0 6px; font-size: 1.25rem; }
.post-meta { font-size: .82rem; color: var(--text-soft); margin-bottom: 10px; }
.post-body p { color: var(--text-soft); margin: 0 0 12px; }

/* About */
.about-grid { display: grid; grid-template-columns: 1fr 2fr; gap: 36px; align-items: start; }
.avatar { width: 100%; aspect-ratio: 1; border-radius: 18px; background: linear-gradient(135deg, var(--accent), var(--accent-2)); display: grid; place-items: center; color: #fff; font-size: 3rem; font-weight: 800; }
.skills { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 14px; }
.skills span { background: var(--accent-soft); color: var(--accent); border-radius: 999px; padding: 6px 14px; font-size: .85rem; font-weight: 600; }
.certs { list-style: none; padding: 0; margin: 18px 0 0; display: grid; gap: 10px; }
.certs li { background: var(--bg-soft); border: 1px solid var(--border); border-radius: 10px; padding: 12px 16px; font-weight: 600; }

/* Contact */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 36px; }
.field { margin-bottom: 16px; }
.field label { display: block; font-weight: 600; margin-bottom: 6px; }
.field input, .field textarea { width: 100%; padding: 12px 14px; border-radius: 10px; border: 1px solid var(--border); background: var(--bg-soft); color: var(--text); font: inherit; }
.field textarea { min-height: 130px; resize: vertical; }
.contact-info a { font-weight: 600; }

/* Footer */
.site-footer { border-top: 1px solid var(--border); padding: 40px 0; background: var(--bg-soft); margin-top: 30px; }
.footer-inner { display: flex; justify-content: space-between; align-items: center; gap: 20px; flex-wrap: wrap; }
.social a { margin-right: 14px; font-weight: 600; }

/* Single post */
.post-article { max-width: 760px; margin: 0 auto; }
.post-article h1 { font-size: 2.3rem; line-height: 1.2; margin-bottom: 8px; }
.post-article .lead { font-size: 1.2rem; color: var(--text-soft); }
.post-article h2 { margin-top: 1.6em; }
.post-article ul { padding-left: 1.2em; }
.post-article li { margin: 6px 0; }

/* Responsive */
@media (max-width: 860px) {
  .nav { position: fixed; top: var(--header-h); right: 0; height: calc(100vh - var(--header-h)); width: 260px; flex-direction: column; align-items: flex-start; background: var(--surface); border-left: 1px solid var(--border); padding: 24px; transform: translateX(110%); transition: transform .3s ease; gap: 18px; }
  .nav.open { transform: translateX(0); }
  .menu-toggle { display: grid; }
  .cards-3, .cards-2, .post-card, .about-grid, .contact-grid { grid-template-columns: 1fr; }
  .post-card .post-thumb { min-height: 120px; }
  .post-body { padding: 0 22px 22px; }
  .slides { min-height: 520px; }
}