:root {
  color-scheme: light dark;
  --bg: #0b1020;
  --bg-accent: #121933;
  --surface: rgba(255, 255, 255, 0.08);
  --surface-strong: rgba(255, 255, 255, 0.12);
  --text: #f5f7ff;
  --muted: #c0c7dd;
  --border: rgba(255, 255, 255, 0.14);
  --shadow: 0 20px 45px rgba(0, 0, 0, 0.25);
  --accent: #7c9cff;
  --accent-strong: #9eb3ff;
  --success: #7ee081;
  font-family: "Pretendard", "Noto Sans KR", system-ui, -apple-system, BlinkMacSystemFont,
    "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top, rgba(124, 156, 255, 0.22), transparent 32%),
    linear-gradient(180deg, var(--bg) 0%, #050813 100%);
  color: var(--text);
}

a {
  color: inherit;
}

.page-shell {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 72px 0 96px;
}

.hero {
  display: grid;
  gap: 24px;
  margin-bottom: 40px;
}

.eyebrow {
  margin: 0;
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent-strong);
}

.hero h1 {
  margin: 0;
  font-size: clamp(2.2rem, 4vw, 4rem);
  line-height: 1.08;
}

.hero p {
  margin: 0;
  max-width: 760px;
  font-size: 1.03rem;
  line-height: 1.7;
  color: var(--muted);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero-outline {
  margin-top: 8px;
  display: grid;
  gap: 10px;
  max-width: 520px;
}

.hero-outline-heading {
  margin: 0;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--muted);
  letter-spacing: 0.02em;
}

.hero-outline-dropdown {
  border-radius: 16px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.04);
  overflow: hidden;
}

.hero-outline-summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 16px;
  min-height: 48px;
  font-weight: 600;
  font-size: 0.96rem;
  color: var(--text);
  user-select: none;
  transition: background-color 150ms ease;
}

.hero-outline-summary::-webkit-details-marker {
  display: none;
}

.hero-outline-summary::after {
  content: "";
  flex-shrink: 0;
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--muted);
  border-bottom: 2px solid var(--muted);
  transform: rotate(45deg) translateY(-3px);
  transition: transform 150ms ease;
}

.hero-outline-dropdown[open] > .hero-outline-summary::after {
  transform: rotate(225deg) translateY(2px);
}

.hero-outline-summary:hover,
.hero-outline-summary:focus-visible {
  background: rgba(255, 255, 255, 0.06);
  outline: none;
}

.hero-outline-dropdown[open] > .hero-outline-summary {
  border-bottom: 1px solid var(--border);
}

.hero-outline-list {
  list-style: none;
  margin: 0;
  padding: 6px 0;
  max-height: min(50vh, 360px);
  overflow-y: auto;
}

.hero-outline-list a {
  display: flex;
  flex-direction: column;
  gap: 3px;
  padding: 10px 16px;
  color: inherit;
  text-decoration: none;
  transition: background-color 130ms ease;
}

.hero-outline-list a:hover,
.hero-outline-list a:focus-visible {
  background: rgba(124, 156, 255, 0.12);
  outline: none;
}

.hero-outline-entry-title {
  font-weight: 600;
  font-size: 0.9rem;
  word-break: break-all;
}

.hero-outline-entry-sub {
  font-size: 0.78rem;
  color: var(--muted);
  line-height: 1.35;
}

.button-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 18px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-strong);
  text-decoration: none;
  font-weight: 600;
  transition: transform 150ms ease, border-color 150ms ease, background-color 150ms ease;
}

.button-link:hover,
.button-link:focus-visible,
.card-link:hover,
.card-link:focus-visible {
  transform: translateY(-1px);
  border-color: rgba(158, 179, 255, 0.55);
}

.button-link.primary {
  background: linear-gradient(135deg, var(--accent) 0%, #5d74e7 100%);
  border-color: transparent;
}

.meta-strip {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 14px;
  margin-bottom: 28px;
}

.meta-card,
.exercise-card {
  border: 1px solid var(--border);
  border-radius: 24px;
  background: var(--surface);
  box-shadow: var(--shadow);
  backdrop-filter: blur(14px);
}

.meta-card {
  padding: 18px 20px;
}

.meta-label {
  display: block;
  margin-bottom: 8px;
  font-size: 0.84rem;
  color: var(--muted);
}

.meta-value {
  font-size: 1.05rem;
  font-weight: 700;
}

.section-heading {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 20px;
}

.section-heading h2,
.empty-state h2 {
  margin: 0;
  font-size: 1.55rem;
}

.section-heading p,
.empty-state p {
  margin: 0;
  color: var(--muted);
  line-height: 1.65;
}

.exercise-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 18px;
}

.exercise-card {
  display: grid;
  gap: 16px;
  padding: 22px;
}

.exercise-card header {
  display: grid;
  gap: 10px;
}

.exercise-card h3 {
  margin: 0;
  font-size: 1.18rem;
}

.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.badge {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 0 10px;
  border-radius: 999px;
  background: rgba(124, 156, 255, 0.15);
  color: var(--accent-strong);
  font-size: 0.85rem;
}

.badge.success {
  background: rgba(126, 224, 129, 0.14);
  color: #b4f0b6;
}

.badge.warn {
  background: rgba(255, 196, 90, 0.16);
  color: #ffd79a;
}

.card-api-note {
  margin: 0;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid rgba(255, 214, 150, 0.35);
  background: rgba(255, 196, 90, 0.08);
  font-size: 0.93rem;
  line-height: 1.62;
}

.card-api-note code {
  font-size: 0.84em;
  padding: 0.06em 0.28em;
  border-radius: 6px;
  background: rgba(0, 0, 0, 0.2);
}

.exercise-card p {
  margin: 0;
  color: var(--muted);
  line-height: 1.65;
}

.path-label {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 0.86rem;
  color: #d9def0;
}

.card-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: fit-content;
  min-height: 44px;
  padding: 0 16px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.04);
  text-decoration: none;
  font-weight: 600;
  transition: transform 150ms ease, border-color 150ms ease;
}

.card-link-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.empty-state {
  padding: 32px;
  text-align: center;
}

.page-footer {
  margin-top: 36px;
  color: var(--muted);
  font-size: 0.92rem;
}

@media (max-width: 640px) {
  .page-shell {
    width: min(100% - 20px, 1120px);
    padding-top: 48px;
    padding-bottom: 72px;
  }

  .hero-actions,
  .section-heading {
    flex-direction: column;
    align-items: stretch;
  }

  .button-link,
  .card-link {
    width: 100%;
  }
}