:root {
  --bg: #0b0f14;
  --bg-2: #121823;
  --ink: #e6edf3;
  --muted: #98a4b3;
  --accent: #4dd0e1;
  --accent-2: #7ee787;
  --card: #111823;
  --border: #1f2a37;
  --code-bg: #0f1722;
  --code-ink: #e6edf3;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", sans-serif;
  color: var(--ink);
  background: radial-gradient(1200px 800px at 8% -10%, #142033 0%, var(--bg) 50%),
    radial-gradient(900px 600px at 100% 0%, #0f2b2e 0%, var(--bg) 45%),
    var(--bg);
  min-height: 100vh;
}

body.modal-open {
  overflow: hidden;
}

.hero {
  position: relative;
  padding: 64px 6vw 48px;
}

.hero::after {
  content: "";
  position: absolute;
  inset: 16px 6vw auto auto;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, rgba(77, 208, 225, 0.25), transparent 60%);
  pointer-events: none;
}

.hero-inner {
  max-width: 980px;
  margin: 0 auto;
  display: grid;
  gap: 16px;
}

.eyebrow {
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--muted);
  margin: 0;
}

.hero h1 {
  font-family: "Fraunces", "Noto Serif SC", serif;
  font-size: clamp(2.6rem, 5vw, 4.1rem);
  margin: 0;
}

.subtitle {
  font-size: 1.1rem;
  color: var(--muted);
  margin: 0;
  max-width: 640px;
}

.meta {
  display: inline-flex;
  gap: 12px;
  align-items: center;
  padding: 10px 16px;
  border-radius: 999px;
  background: #0f1722;
  border: 1px solid var(--border);
  width: fit-content;
  font-size: 0.95rem;
}

.meta-label {
  color: var(--muted);
}

.layout {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 6vw 64px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 32px;
}

.content {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 28px;
  padding: 40px 40px 48px;
  box-shadow: var(--shadow);
}

.content > * {
  opacity: 0;
  transform: translateY(10px);
  animation: rise 0.7s ease forwards;
  animation-delay: calc(var(--i, 0) * 60ms);
}

.content h1,
.content h2,
.content h3 {
  font-family: "Fraunces", "Noto Serif SC", serif;
  scroll-margin-top: 120px;
}

.content h2 {
  margin-top: 36px;
  padding-left: 14px;
  border-left: 4px solid var(--accent);
}

.content h1 {
  margin-top: 0;
}

.content p {
  line-height: 1.75;
}

.content a {
  color: var(--accent-2);
  text-decoration: none;
  border-bottom: 1px solid rgba(126, 231, 135, 0.35);
}

.content a:hover {
  color: var(--accent);
  border-bottom-color: rgba(77, 208, 225, 0.6);
}

.content ul,
.content ol {
  padding-left: 20px;
}

.content code {
  font-family: "JetBrains Mono", "SFMono-Regular", ui-monospace, monospace;
  font-size: 0.95rem;
  background: rgba(77, 208, 225, 0.12);
  padding: 2px 6px;
  border-radius: 6px;
}

.content pre,
.modal-body pre {
  position: relative;
  padding: 18px 72px 16px 16px;
  background: var(--code-bg);
  border-radius: 16px;
  border: 1px solid var(--border);
  overflow: auto;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05);
}

.content pre code,
.modal-body pre code {
  display: block;
  background: transparent;
  padding: 0;
  color: var(--code-ink);
  font-size: 0.92rem;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  word-break: break-word;
}

.copy-btn {
  position: absolute;
  top: 10px;
  right: 12px;
  border: none;
  background: #0b111a;
  border-radius: 999px;
  padding: 6px 12px;
  font-size: 0.8rem;
  cursor: pointer;
  color: var(--muted);
  box-shadow: 0 6px 12px rgba(0, 0, 0, 0.4);
  transition: transform 0.2s ease, color 0.2s ease;
}

.copy-btn:hover {
  transform: translateY(-1px);
  color: var(--accent);
}

.sidebar {
  display: grid;
  gap: 20px;
  align-content: start;
  position: sticky;
  top: 24px;
  height: fit-content;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 20px;
  box-shadow: var(--shadow);
}

.card h3 {
  margin-top: 0;
  font-family: "Fraunces", "Noto Serif SC", serif;
}

.card button {
  width: 100%;
  margin-top: 10px;
}

.toc a {
  display: block;
  padding: 6px 0;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
}

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

.toc .toc-easter {
  margin-top: 8px;
  color: var(--accent-2);
  font-weight: 600;
}

.appendix {
  max-width: 1200px;
  margin: 0 auto 96px;
  padding: 0 6vw;
}

.appendix-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
}

.appendix-head h2 {
  font-family: "Fraunces", "Noto Serif SC", serif;
  margin: 0;
}

.appendix-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
}

.appendix-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 18px;
  box-shadow: var(--shadow);
  display: grid;
  gap: 10px;
  opacity: 0;
  transform: translateY(10px);
  animation: rise 0.7s ease forwards;
  animation-delay: calc(var(--i, 0) * 80ms + 200ms);
}

.appendix-card h3 {
  margin: 0;
}

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

.site-footer {
  text-align: center;
  color: var(--muted);
  padding: 0 6vw 40px;
  font-size: 0.95rem;
}

button,
.btn {
  border: none;
  border-radius: 999px;
  padding: 10px 16px;
  font-size: 0.95rem;
  cursor: pointer;
  background: linear-gradient(135deg, var(--accent), #1f8ea3);
  color: #fff;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

button:hover,
.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 18px rgba(77, 208, 225, 0.3);
}

button.secondary {
  background: #0f1722;
  color: var(--muted);
  border: 1px solid var(--border);
  box-shadow: none;
}

.modal {
  position: fixed;
  inset: 0;
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 20;
}

.modal.is-open {
  display: flex;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(8, 10, 14, 0.65);
  backdrop-filter: blur(4px);
}

.modal-panel {
  position: relative;
  background: var(--card);
  border-radius: 24px;
  max-width: 900px;
  width: min(92vw, 900px);
  max-height: 80vh;
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  display: grid;
  grid-template-rows: auto 1fr;
  animation: rise 0.3s ease;
}

.modal-header {
  padding: 18px 22px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border);
}

.modal-header h3 {
  margin: 0;
  font-family: "Fraunces", "Noto Serif SC", serif;
}

.modal-body {
  padding: 20px 22px 24px;
  overflow: auto;
}

.modal-body pre {
  margin-top: 0;
}

.modal-close {
  background: #0f1722;
  color: var(--muted);
  border: 1px solid var(--border);
  padding: 6px 12px;
  font-size: 0.85rem;
  border-radius: 999px;
  cursor: pointer;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 960px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
    order: -1;
  }
}

@media (max-width: 640px) {
  .content pre,
  .modal-body pre {
    padding-right: 16px;
  }

  .copy-btn {
    position: static;
    margin-bottom: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation: none !important;
    transition: none !important;
  }
}