:root {
  --bg: #0b1220;
  --bg-top: #16213a;
  --surface: #121a2b;
  --text: #e6edf8;
  --muted: #a2b0c8;
  --primary: #61dafb;
  --primary-dark: #3bbfe4;
  --border: #24314a;
  --brand: #f2f7ff;
  --nav-bg: #0f182c;
  --header-bg: rgba(8, 14, 28, 0.9);
  --card-bg: rgba(18, 26, 43, 0.9);
  --tag-text: #9ad8ff;
  --tag-bg: #10253f;
  --tag-border: #214469;
}

:root[data-theme="light"] {
  --bg: #f4f7fc;
  --bg-top: #ffffff;
  --surface: #eef3fb;
  --text: #1c2a42;
  --muted: #52627c;
  --primary: #0077cc;
  --primary-dark: #0068b3;
  --border: #cfd9e8;
  --brand: #122239;
  --nav-bg: #ffffff;
  --header-bg: rgba(255, 255, 255, 0.9);
  --card-bg: rgba(255, 255, 255, 0.9);
  --tag-text: #0d5f9f;
  --tag-bg: #deeffe;
  --tag-border: #9dc8e8;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: radial-gradient(circle at top, var(--bg-top), var(--bg) 42%);
  line-height: 1.6;
}

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

a:hover {
  text-decoration: underline;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 1.25rem;
  background: var(--header-bg);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.brand {
  font-weight: 700;
  letter-spacing: 0.2px;
  color: var(--brand);
}

.site-nav {
  display: flex;
  gap: 1rem;
}

.site-nav a {
  color: var(--text);
  font-weight: 500;
}

.menu-toggle {
  display: none;
  border: 1px solid var(--border);
  color: var(--text);
  background: var(--surface);
  padding: 0.4rem 0.75rem;
  border-radius: 0.5rem;
}

.theme-toggle,
.lang-toggle {
  border: 1px solid var(--border);
  color: var(--text);
  background: var(--surface);
  padding: 0.4rem 0.75rem;
  border-radius: 0.5rem;
  cursor: pointer;
}

main {
  max-width: 980px;
  margin: 0 auto;
  padding: 2rem 1.25rem 4rem;
}

.hero {
  padding: 3rem 0 2rem;
}

.eyebrow {
  margin: 0;
  color: var(--primary);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.82rem;
}

h1 {
  margin: 0.4rem 0 1rem;
  font-size: clamp(1.85rem, 5vw, 3rem);
  line-height: 1.15;
}

h2 {
  margin: 0 0 1rem;
  font-size: clamp(1.4rem, 3vw, 2rem);
}

.hero p {
  color: var(--muted);
  max-width: 680px;
}

.hero-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1.2rem;
}

.btn {
  display: inline-block;
  padding: 0.58rem 0.95rem;
  border-radius: 0.55rem;
  font-weight: 600;
  border: 1px solid transparent;
  transition: transform 0.16s ease, background-color 0.16s ease;
}

.btn:hover {
  transform: translateY(-1px);
  text-decoration: none;
}

.btn.primary {
  background: var(--primary);
  color: #0a1020;
}

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

.btn.secondary {
  border-color: var(--border);
  color: var(--text);
}

.section {
  margin-top: 2.2rem;
}

.cards {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.9rem;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 0.8rem;
  padding: 1rem;
}

.card h3 {
  margin: 0 0 0.4rem;
}

.card p {
  margin: 0;
  color: var(--muted);
}

.tag {
  display: inline-block;
  margin-top: 0.7rem;
  font-size: 0.78rem;
  color: var(--tag-text);
  background: var(--tag-bg);
  border: 1px solid var(--tag-border);
  border-radius: 999px;
  padding: 0.15rem 0.5rem;
}

.skills,
.contact-list {
  padding-left: 1.1rem;
  color: var(--muted);
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.2rem;
  text-align: center;
  color: var(--muted);
}

@media (max-width: 760px) {
  .menu-toggle {
    display: inline-block;
  }

  .site-nav {
    position: absolute;
    top: 100%;
    right: 1rem;
    left: 1rem;
    display: none;
    flex-direction: column;
    border: 1px solid var(--border);
    border-radius: 0.8rem;
    background: var(--nav-bg);
    padding: 0.8rem;
  }

  .site-nav.open {
    display: flex;
  }

  .cards {
    grid-template-columns: 1fr;
  }
}