:root {
  --bg: #0e1117;
  --surface: #161b26;
  --surface2: #1e2638;
  --border: #2a3347;
  --accent: #4f9cf9;
  --accent2: #f59e0b;
  --accent3: #22d3a5;
  --text: #e2e8f0;
  --text2: #94a3b8;
  --text3: #64748b;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background:
    radial-gradient(1200px 420px at 10% -10%, rgba(79, 156, 249, 0.24), transparent 60%),
    radial-gradient(900px 380px at 100% -10%, rgba(245, 158, 11, 0.16), transparent 65%),
    var(--bg);
  color: var(--text);
  font-family: 'DM Sans', sans-serif;
  min-height: 100vh;
}

header {
  background: rgba(22, 27, 38, 0.95);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--border);
  padding: 1.2rem 2rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-badge {
  background: linear-gradient(135deg, #f59e0b, #22d3a5);
  color: #0a0f1b;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  padding: 3px 10px;
  border-radius: 999px;
  text-transform: uppercase;
}

.header-text {
  flex: 1;
}

header h1 {
  font-size: 18px;
  font-weight: 600;
}

header p {
  font-size: 13px;
  color: var(--text2);
}

.day-nav {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.day-link {
  font-size: 12px;
  font-weight: 500;
  padding: 5px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface2);
  color: var(--text2);
  text-decoration: none;
  transition: all 0.15s ease;
}

.day-link:hover {
  color: var(--text);
  border-color: var(--accent);
}

.day-link.current {
  color: var(--accent2);
  border-color: var(--accent2);
  background: rgba(245, 158, 11, 0.12);
}

.day-link.home-link {
  color: var(--accent3);
  border-color: var(--accent3);
  background: rgba(34, 211, 165, 0.08);
}

.container {
  max-width: 980px;
  margin: 0 auto;
  padding: 2rem;
  display: grid;
  gap: 1rem;
}

.card {
  background: rgba(22, 27, 38, 0.92);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.2rem 1.4rem;
}

.hero h2 {
  font-size: clamp(1.25rem, 2.5vw, 1.75rem);
  margin-bottom: 0.45rem;
}

.hero p {
  color: var(--text2);
  line-height: 1.6;
}

.quick-grid {
  margin-top: 1rem;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.6rem;
}

.quick-link {
  text-decoration: none;
  text-align: center;
  font-weight: 600;
  color: var(--text);
  padding: 0.6rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: linear-gradient(135deg, rgba(79, 156, 249, 0.18), rgba(30, 38, 56, 0.5));
}

.quick-link:hover {
  border-color: var(--accent);
}

.toc h3,
.card h3 {
  margin-bottom: 0.6rem;
}

.toc ul {
  list-style: none;
  display: grid;
  gap: 0.45rem;
}

.toc a {
  color: var(--accent);
  text-decoration: none;
}

.toc a:hover {
  text-decoration: underline;
}

.section-tag {
  display: inline-block;
  margin-bottom: 0.5rem;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent2);
}

.card p,
.card li {
  color: var(--text2);
  line-height: 1.65;
}

.card ol {
  padding-left: 1.25rem;
  margin-bottom: 0.8rem;
  display: grid;
  gap: 0.3rem;
}

.code-wrap {
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
  background: #0a0e17;
}

.code-topbar {
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
  padding: 0.45rem 0.75rem;
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  color: var(--text3);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem;
}

.copy-btn {
  border: 1px solid var(--border);
  background: rgba(79, 156, 249, 0.12);
  color: #b8d5ff;
  font-family: 'DM Sans', sans-serif;
  font-size: 11px;
  font-weight: 600;
  border-radius: 6px;
  padding: 0.18rem 0.5rem;
  cursor: pointer;
}

.copy-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}

.copy-btn.copied {
  border-color: var(--accent3);
  color: var(--accent3);
  background: rgba(34, 211, 165, 0.12);
}

.helper-actions {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin: 0.75rem 0;
}

.mode-btn {
  border: 1px solid var(--border);
  background: var(--surface2);
  color: var(--text2);
  font-family: 'DM Sans', sans-serif;
  font-size: 12px;
  font-weight: 600;
  border-radius: 8px;
  padding: 0.35rem 0.75rem;
  cursor: pointer;
}

.mode-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}

.mode-btn.is-active {
  border-color: var(--accent2);
  color: var(--accent2);
  background: rgba(245, 158, 11, 0.12);
}

.code-wrap.compact pre {
  font-size: 11.5px;
}

pre {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  line-height: 1.85;
  color: #d6e2ff;
  padding: 0.9rem 1rem;
  overflow-x: auto;
}

.note {
  margin-top: 0.55rem;
  font-size: 13px;
}

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.8rem;
}

.split h4 {
  font-size: 14px;
  margin-bottom: 0.4rem;
}

details {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface2);
  padding: 0.75rem 0.85rem;
  margin-top: 0.55rem;
}

summary {
  cursor: pointer;
  font-weight: 600;
}

details p {
  margin-top: 0.55rem;
}

code {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: #f8d477;
}

.next-steps {
  text-align: center;
}

.cta {
  display: inline-block;
  margin-top: 0.8rem;
  text-decoration: none;
  color: #0a0f1b;
  font-weight: 700;
  border-radius: 999px;
  padding: 0.6rem 1.1rem;
  background: linear-gradient(135deg, #22d3a5, #4f9cf9);
}

@media (max-width: 900px) {
  header {
    flex-wrap: wrap;
    align-items: flex-start;
  }

  .day-nav {
    width: 100%;
  }

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

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

@media (max-width: 640px) {
  .container {
    padding: 1rem;
  }

  header {
    padding: 1rem;
  }
}