/* ── Fluent 2 Design Tokens ── */
:root {
  --font-family: "Segoe UI Variable", "Segoe UI", system-ui, -apple-system,
    "PingFang SC", "Microsoft YaHei", sans-serif;

  --accent: #0078d4;
  --accent-hover: #106ebe;
  --accent-subtle: rgba(0, 120, 212, 0.12);
  --accent-glow: rgba(0, 120, 212, 0.35);

  --bg-base: #f3f3f3;
  --bg-elevated: rgba(255, 255, 255, 0.72);
  --bg-subtle: rgba(255, 255, 255, 0.45);
  --text-primary: #1a1a1a;
  --text-secondary: #616161;
  --text-tertiary: #949494;
  --stroke-default: rgba(0, 0, 0, 0.06);
  --stroke-subtle: rgba(255, 255, 255, 0.6);

  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.08);

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 999px;

  --blur-acrylic: 24px;
  --blur-ambient: 80px;
  --header-blur: 24px;

  --ease-out: cubic-bezier(0, 0, 0, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --duration-fast: 150ms;
  --duration-normal: 250ms;
  --duration-slow: 400ms;

  --container: 1080px;
  --header-height: 56px;
}

[data-theme="dark"] {
  --accent: #479ef5;
  --accent-hover: #62abf5;
  --accent-subtle: rgba(71, 158, 245, 0.15);
  --accent-glow: rgba(71, 158, 245, 0.4);

  --bg-base: #0a0a0a;
  --bg-elevated: rgba(32, 32, 32, 0.75);
  --bg-subtle: rgba(255, 255, 255, 0.06);
  --text-primary: #f5f5f5;
  --text-secondary: #adadad;
  --text-tertiary: #6e6e6e;
  --stroke-default: rgba(255, 255, 255, 0.08);
  --stroke-subtle: rgba(255, 255, 255, 0.12);

  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.45);
}

/* ── Reset ── */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family);
  font-size: 15px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-base);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  transition: background var(--duration-normal) var(--ease-out),
    color var(--duration-normal) var(--ease-out);
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-out);
}

a:hover {
  color: var(--accent-hover);
}

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Ambient Background ── */
.ambient {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}

.ambient__orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(var(--blur-ambient));
  opacity: 0.55;
  will-change: transform;
  transition: opacity var(--duration-slow) var(--ease-out);
}

[data-theme="dark"] .ambient__orb {
  opacity: 0.35;
}

.ambient__orb--1 {
  width: 520px;
  height: 520px;
  top: -8%;
  right: -6%;
  background: radial-gradient(circle, #0078d4 0%, transparent 70%);
}

.ambient__orb--2 {
  width: 440px;
  height: 440px;
  bottom: 10%;
  left: -8%;
  background: radial-gradient(circle, #8764b8 0%, transparent 70%);
}

.ambient__orb--3 {
  width: 360px;
  height: 360px;
  top: 42%;
  left: 38%;
  background: radial-gradient(circle, #00b7c3 0%, transparent 70%);
}

.ambient__mesh {
  position: absolute;
  inset: 0;
  background-image: radial-gradient(
    rgba(0, 0, 0, 0.03) 1px,
    transparent 1px
  );
  background-size: 24px 24px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 30%, black, transparent);
}

[data-theme="dark"] .ambient__mesh {
  background-image: radial-gradient(
    rgba(255, 255, 255, 0.04) 1px,
    transparent 1px
  );
}

/* ── Acrylic Material ── */
.acrylic {
  background: var(--bg-elevated);
  backdrop-filter: blur(var(--header-blur)) saturate(1.4);
  -webkit-backdrop-filter: blur(var(--header-blur)) saturate(1.4);
  border: 1px solid var(--stroke-default);
  box-shadow: var(--shadow-sm);
}

.acrylic-subtle {
  background: var(--bg-subtle);
  backdrop-filter: blur(12px) saturate(1.2);
  -webkit-backdrop-filter: blur(12px) saturate(1.2);
  border: 1px solid var(--stroke-default);
}

@supports not (backdrop-filter: blur(1px)) {
  .acrylic,
  .acrylic-subtle,
  .site-header,
  .site-footer {
    background: var(--bg-base);
  }
}

/* ── Header ── */
.site-header {
  position: fixed;
  top: 16px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 200;
  width: calc(100% - 32px);
  max-width: calc(var(--container) - 8px);
  border-radius: var(--radius-lg);
  transition: box-shadow var(--duration-normal) var(--ease-out),
    backdrop-filter var(--duration-normal) var(--ease-out),
    top var(--duration-normal) var(--ease-out);
}

.site-header.is-scrolled {
  top: 10px;
  box-shadow: var(--shadow-md);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 15px;
  letter-spacing: -0.01em;
}

.logo:hover {
  color: var(--text-primary);
}

.logo-mark {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  background: var(--accent-subtle);
  color: var(--accent);
}

.nav {
  display: flex;
  gap: 4px;
  padding: 4px;
  border-radius: var(--radius-md);
  background: var(--bg-subtle);
}

.nav-link {
  padding: 6px 16px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: background var(--duration-fast) var(--ease-out),
    color var(--duration-fast) var(--ease-out);
}

.nav-link:hover {
  color: var(--text-primary);
  background: var(--bg-elevated);
}

.icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  transition: background var(--duration-fast) var(--ease-out),
    color var(--duration-fast) var(--ease-out),
    transform var(--duration-fast) var(--ease-spring);
}

.icon-btn:hover {
  color: var(--text-primary);
  transform: scale(1.05);
}

.icon-btn:active {
  transform: scale(0.96);
}

.icon-btn svg {
  display: none;
}

[data-theme-pref="light"] .icon-sun,
[data-theme-pref="dark"] .icon-moon,
[data-theme-pref="system"] .icon-system {
  display: block;
}

/* ── Main ── */
.main {
  position: relative;
  z-index: 1;
  flex: 1;
  padding-top: calc(var(--header-height) + 48px);
}

/* ── Hero ── */
.hero {
  padding: 48px 0 64px;
}

.hero-panel {
  position: relative;
  padding: 56px 48px;
  border-radius: var(--radius-xl);
  text-align: center;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.hero-panel::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    135deg,
    var(--accent-subtle) 0%,
    transparent 50%
  );
  pointer-events: none;
}

.hero-eyebrow {
  position: relative;
  display: inline-block;
  margin-bottom: 12px;
  padding: 4px 12px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-subtle);
  border-radius: var(--radius-full);
}

.hero-title {
  position: relative;
  font-size: clamp(2.25rem, 6vw, 3.25rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 16px;
  background: linear-gradient(135deg, var(--text-primary) 30%, var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  position: relative;
  font-size: 17px;
  color: var(--text-secondary);
  max-width: 420px;
  margin: 0 auto 28px;
  line-height: 1.65;
}

.hero-tags {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

/* ── Chips ── */
.chip {
  display: inline-flex;
  align-items: center;
  padding: 5px 14px;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-subtle);
  border: 1px solid var(--stroke-default);
  border-radius: var(--radius-full);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: border-color var(--duration-fast) var(--ease-out),
    color var(--duration-fast) var(--ease-out);
}

.chip-accent {
  color: var(--accent);
  background: var(--accent-subtle);
  border-color: transparent;
}

.chip-sm {
  padding: 3px 10px;
  font-size: 12px;
}

/* ── Sections ── */
.section {
  padding: 32px 0 64px;
}

.section-head {
  margin-bottom: 24px;
}

.section-eyebrow {
  display: block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 6px;
}

.section-title {
  font-size: 1.625rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
}

/* ── About ── */
.about-panel {
  position: relative;
  padding: 32px 36px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.about-accent {
  position: absolute;
  left: 0;
  top: 20%;
  bottom: 20%;
  width: 4px;
  border-radius: 0 4px 4px 0;
  background: linear-gradient(180deg, var(--accent), transparent);
}

.about-text {
  font-size: 16px;
  line-height: 1.75;
  color: var(--text-secondary);
  padding-left: 12px;
}

.about-text strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* ── Posts Grid ── */
.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 16px;
}

.post-card {
  display: flex;
  flex-direction: column;
  padding: 24px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: transform var(--duration-normal) var(--ease-out),
    box-shadow var(--duration-normal) var(--ease-out),
    border-color var(--duration-normal) var(--ease-out);
}

.post-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent-subtle);
}

.post-card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

.post-date {
  font-size: 12px;
  font-weight: 500;
  color: var(--text-tertiary);
  font-variant-numeric: tabular-nums;
}

.post-title {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.45;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.post-summary {
  flex: 1;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: auto;
}

/* ── Footer ── */
.site-footer {
  position: relative;
  z-index: 1;
  margin: 0 16px 16px;
  border-radius: var(--radius-lg);
  padding: 20px 24px;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-tertiary);
}

.footer-domain {
  font-weight: 600;
  color: var(--text-secondary);
}

.footer-divider {
  opacity: 0.4;
}

.footer-icp {
  color: var(--text-tertiary);
}

.footer-icp:hover {
  color: var(--accent);
}

/* ── Reveal Animation ── */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
  transition-delay: var(--reveal-delay, 0ms);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .site-header {
    top: 10px;
    width: calc(100% - 20px);
    border-radius: var(--radius-md);
  }

  .nav {
    display: none;
  }

  .hero-panel {
    padding: 40px 24px;
    border-radius: var(--radius-lg);
  }

  .hero {
    padding: 32px 0 48px;
  }

  .about-panel {
    padding: 24px 20px;
  }

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

  .footer-inner {
    flex-direction: column;
    gap: 4px;
  }

  .footer-divider {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .ambient__orb {
    animation: none !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}