:root {
  /* grayscale palette — hierarchy via font-weight and lightness only */
  --accent: #2b2b2b;
  --accent-text: #f5f5f5;
  --danger: #555555;
  --success: #666666;

  /* typography */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-serif: "Noto Serif KR", Georgia, "Times New Roman", serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  /* spacing scale */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;

  /* radii */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  /* motion */
  --transition-fast: 150ms ease;
  --transition-base: 220ms ease;
  --transition-slow: 350ms ease;
}

[data-theme="dark"] {
  --bg: oklch(18% 0.01 260);
  --bg-elevated: oklch(22% 0.01 260);
  --surface: oklch(26% 0.02 260);
  --surface-hover: oklch(30% 0.03 260);
  --border: oklch(35% 0.03 260);
  --border-subtle: oklch(30% 0.02 260);
  --text: oklch(92% 0.01 260);
  --text-muted: oklch(70% 0.02 260);
  --text-faint: oklch(55% 0.02 260);
  --shadow-color: oklch(8% 0.02 260 / 0.45);
}

[data-theme="light"] {
  --bg: oklch(98% 0.01 100);
  --bg-elevated: oklch(100% 0 0);
  --surface: oklch(96% 0.01 100);
  --surface-hover: oklch(92% 0.01 100);
  --border: oklch(85% 0.02 100);
  --border-subtle: oklch(92% 0.01 100);
  --text: oklch(22% 0.02 100);
  --text-muted: oklch(50% 0.03 100);
  --text-faint: oklch(60% 0.02 100);
  --shadow-color: oklch(50% 0.02 100 / 0.12);
}

[data-theme="newsprint"] {
  --bg: #f7f7f7;
  --bg-elevated: #ffffff;
  --surface: #ffffff;
  --surface-hover: #f0f0f0;
  --border: #d4d4d4;
  --border-subtle: #e6e6e6;
  --text: #1a1a1a;
  --text-muted: #555555;
  --text-faint: #888888;
  --accent: #2b2b2b;
  --accent-text: #ffffff;
  --shadow-color: rgba(0, 0, 0, 0.08);
  --font-headline: "Noto Serif KR", Georgia, "Times New Roman", serif;
}

[data-theme="sepia"] {
  --bg: oklch(92% 0.03 80);
  --bg-elevated: oklch(94% 0.03 80);
  --surface: oklch(88% 0.04 80);
  --surface-hover: oklch(84% 0.04 80);
  --border: oklch(70% 0.05 80);
  --border-subtle: oklch(80% 0.04 80);
  --text: oklch(25% 0.04 80);
  --text-muted: oklch(45% 0.05 80);
  --text-faint: oklch(55% 0.05 80);
  --accent: oklch(45% 0.12 50);
  --accent-text: oklch(95% 0.02 50);
  --shadow-color: oklch(30% 0.05 80 / 0.2);
}

* {
  box-sizing: border-box;
}

html {
  font-size: var(--type-base, 16px);
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-wrap: pretty;
}

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

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

/* Masthead */
.masthead {
  border-bottom: 1px solid var(--border);
  background: var(--bg-elevated);
}

.masthead-inner {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-10) var(--space-5);
}

.kicker {
  margin: 0 0 var(--space-2);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
}

.title {
  margin: 0;
  font-family: var(--font-serif);
  font-size: clamp(2.4rem, 8vw, 4rem);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.03em;
}

.lede {
  margin: var(--space-4) 0 0;
  max-width: 48ch;
  color: var(--text-muted);
  font-size: 1.05rem;
  line-height: 1.6;
}

.toolbar {
  margin-top: var(--space-6);
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
  align-items: center;
}

.search-wrap {
  position: relative;
  flex: 1 1 240px;
  min-width: 200px;
}

.search-wrap .icon {
  position: absolute;
  left: var(--space-3);
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-faint);
  pointer-events: none;
}

.search-wrap input {
  width: 100%;
  padding: var(--space-3) var(--space-3) var(--space-3) 2.4rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--surface);
  color: var(--text);
  font-size: 0.95rem;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.search-wrap input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(43, 43, 43, 0.15);
}

.filter-group select {
  padding: var(--space-3) 2.2rem var(--space-3) var(--space-3);
  border: 1px solid var(--border);
  border-radius: var(--space-3);
  background: var(--surface);
  color: var(--text);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.6rem center;
  cursor: pointer;
}

.filter-group select:focus {
  outline: none;
  border-color: var(--accent);
}

.meta {
  margin-top: var(--space-4);
  font-size: 0.8rem;
  color: var(--text-faint);
  font-variant-numeric: tabular-nums;
}

.meta-sep {
  margin: 0 var(--space-2);
}

/* Timeline */
.timeline {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-8) var(--space-5);
}

.loading,
.empty {
  text-align: center;
  padding: var(--space-12) var(--space-5);
  color: var(--text-muted);
}

.year-group {
  position: relative;
  padding-left: var(--space-10);
  margin-bottom: var(--space-8);
}

.year-group::before {
  content: "";
  position: absolute;
  left: 18px;
  top: 0;
  bottom: calc(-1 * var(--space-8));
  width: 1px;
  background: linear-gradient(180deg, var(--border) 80%, transparent);
}

.year-group:last-child::before {
  bottom: 0;
}

.year-label {
  position: sticky;
  top: var(--space-4);
  z-index: 10;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  margin: 0 0 var(--space-6) calc(-1 * var(--space-10));
  padding: var(--space-1) var(--space-3);
  font-family: var(--font-sans);
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  box-shadow: 0 2px 12px var(--shadow-color);
}

.year-label::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
}

/* Events */
.event {
  position: relative;
  margin-bottom: var(--space-6);
}

.event::before {
  content: "";
  position: absolute;
  left: calc(-1 * var(--space-10) + 14px);
  top: var(--space-4);
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--surface);
  border: 2px solid var(--accent);
  z-index: 5;
}

.event-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.event-card:hover {
  transform: translateY(-1px);
  border-color: var(--border);
  box-shadow: 0 6px 20px var(--shadow-color);
}

.event-card:focus-within {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.event-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2) var(--space-3);
  margin-bottom: var(--space-2);
}

.event-date {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.event-category {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 0.1rem 0.5rem;
  border-radius: 999px;
  background: rgba(43, 43, 43, 0.10);
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.event-title {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1.3;
  cursor: pointer;
  transition: color var(--transition-fast);
}

.event-title:hover {
  color: var(--accent);
}

.event-summary {
  margin: var(--space-2) 0 0;
  color: var(--text-muted);
  font-size: 0.97rem;
}

.event-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-3);
}

.tag {
  font-size: 0.78rem;
  color: var(--text-faint);
  cursor: pointer;
  transition: color var(--transition-fast);
}

.tag::before {
  content: "#";
  margin-right: 0.1em;
  color: var(--accent);
}

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

/* Expandable body */
.event-body {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--transition-slow);
}

.event-body.open {
  grid-template-rows: 1fr;
}

.event-body-inner {
  overflow: hidden;
  padding-top: 0;
  opacity: 0.7;
  transition: padding-top var(--transition-slow), opacity var(--transition-slow);
}

.event-body.open .event-body-inner {
  padding-top: var(--space-4);
  opacity: 1;
}

.event-body-inner > *:first-child {
  margin-top: 0;
}

.event-body-inner > *:last-child {
  margin-bottom: 0;
}

.event-body-inner h3,
.event-body-inner h2,
.event-body-inner h1 {
  font-family: var(--font-sans);
  margin: var(--space-4) 0 var(--space-2);
  font-size: 1.05rem;
  font-weight: 700;
}

.event-body-inner p,
.event-body-inner li {
  font-family: var(--font-serif);
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.8;
}

.event-body-inner ul,
.event-body-inner ol {
  padding-left: var(--space-5);
  margin: var(--space-2) 0;
}

.event-body-inner a {
  word-break: break-all;
}

.event-sources {
  margin-top: var(--space-5);
  padding-top: var(--space-4);
  border-top: 1px solid var(--border-subtle);
}

.event-sources h4 {
  margin: 0 0 var(--space-3);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-faint);
}

.event-sources ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.event-sources li {
  margin-bottom: var(--space-2);
}

.event-sources a {
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-2);
  color: var(--text);
  text-decoration: none;
  font-size: 0.93rem;
}

.event-sources a::before {
  content: "→";
  color: var(--accent);
  font-weight: 700;
}

.event-sources a:hover {
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

.event-source-url {
  display: block;
  font-size: 0.75rem;
  color: var(--text-faint);
  margin-top: 0.1rem;
  font-family: var(--font-mono);
}

/* Search highlight */
mark {
  background: #e8e8e8;
  color: inherit;
  padding: 0 0.1em;
  border-radius: 2px;
}

/* Colophon */
.colophon {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-8) var(--space-5);
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-faint);
  font-size: 0.78rem;
}

/* Tweaks toggle */
.tweaks-toggle {
  position: fixed;
  right: var(--space-4);
  bottom: var(--space-4);
  width: 44px;
  height: 44px;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--bg-elevated);
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 16px var(--shadow-color);
  transition: color var(--transition-fast), transform var(--transition-fast);
  z-index: 100;
}

.tweaks-toggle:hover {
  color: var(--accent);
  transform: rotate(30deg);
}

.tweaks-panel {
  position: fixed;
  right: var(--space-4);
  bottom: calc(var(--space-4) + 56px);
  width: min(260px, calc(100vw - var(--space-8)));
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  box-shadow: 0 12px 40px var(--shadow-color);
  z-index: 100;
  opacity: 0;
  transform: translateY(12px) scale(0.98);
  pointer-events: none;
  transition: opacity var(--transition-base), transform var(--transition-base);
}

.tweaks-panel.open {
  opacity: 1;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}

.tweaks-panel fieldset {
  border: none;
  padding: 0;
  margin: 0 0 var(--space-4);
}

.tweaks-panel fieldset:last-child {
  margin-bottom: 0;
}

.tweaks-panel legend {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-faint);
  margin-bottom: var(--space-2);
}

.segmented {
  display: flex;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.segmented label {
  flex: 1;
  text-align: center;
  padding: var(--space-2) var(--space-1);
  font-size: 0.82rem;
  cursor: pointer;
  background: var(--surface);
  color: var(--text-muted);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.segmented label:has(input:checked) {
  background: var(--accent);
  color: var(--accent-text);
}

.segmented input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.tweaks-panel input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}

/* Density variants */
[data-density="compact"] .year-group {
  margin-bottom: var(--space-4);
}

[data-density="compact"] .event {
  margin-bottom: var(--space-3);
}

[data-density="compact"] .event-card {
  padding: var(--space-3) var(--space-4);
}

[data-density="compact"] .year-label {
  margin-bottom: var(--space-4);
}

[data-density="spacious"] .year-group {
  margin-bottom: var(--space-12);
}

[data-density="spacious"] .event {
  margin-bottom: var(--space-8);
}

[data-density="spacious"] .event-card {
  padding: var(--space-6);
}

[data-density="spacious"] .year-label {
  margin-bottom: var(--space-8);
}

/* Responsive */
@media (max-width: 640px) {
  .masthead-inner {
    padding: var(--space-8) var(--space-4);
  }

  .timeline {
    padding: var(--space-6) var(--space-4);
  }

  .year-group {
    padding-left: var(--space-8);
  }

  .year-group::before {
    left: 13px;
  }

  .event::before {
    left: calc(-1 * var(--space-8) + 9px);
  }

  .year-label {
    margin-left: calc(-1 * var(--space-8));
    font-size: 1.2rem;
  }

  .event-title {
    font-size: 1.15rem;
  }

  .tweaks-panel {
    right: var(--space-2);
    bottom: calc(var(--space-2) + 56px);
  }

  .tweaks-toggle {
    right: var(--space-2);
    bottom: var(--space-2);
  }
}

/* Newsprint theme overrides */
[data-theme="newsprint"] .masthead {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

[data-theme="newsprint"] .title {
  color: #111111;
  letter-spacing: -0.02em;
  font-family: var(--font-serif);
}

[data-theme="newsprint"] .kicker {
  color: var(--accent);
  font-family: var(--font-sans);
  letter-spacing: 0.2em;
}

[data-theme="newsprint"] .event-card {
  background: var(--surface);
  border: 1px solid var(--border);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 1px rgba(0, 0, 0, 0.03);
}

[data-theme="newsprint"] .event-card:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  border-color: var(--text-faint);
}

[data-theme="newsprint"] .event-title {
  color: #0f0f0f;
  font-weight: 700;
}

[data-theme="newsprint"] .event-title:hover {
  color: var(--accent);
}

[data-theme="newsprint"] .event-category {
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
  font-weight: 700;
}

[data-theme="newsprint"] .year-group::before {
  background: var(--border);
}

[data-theme="newsprint"] .year-label {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 0;
  font-family: var(--font-sans);
  font-weight: 800;
  box-shadow: 0 1px 3px var(--shadow-color);
}

[data-theme="newsprint"] .year-label::before {
  display: none;
}

[data-theme="newsprint"] .event-title {
  font-family: var(--font-sans);
  color: #0f0f0f;
}

[data-theme="newsprint"] .event-body-inner p,
[data-theme="newsprint"] .event-body-inner li {
  font-family: var(--font-serif);
  color: var(--text-muted);
  line-height: 1.8;
}

[data-theme="newsprint"] .event-body-inner h3,
[data-theme="newsprint"] .event-body-inner h2,
[data-theme="newsprint"] .event-body-inner h1 {
  font-family: var(--font-sans);
  font-weight: 700;
}

[data-theme="newsprint"] .event::before {
  background: var(--accent);
  border-color: var(--surface);
}

[data-theme="newsprint"] .search-wrap input,
[data-theme="newsprint"] .filter-group select {
  background: var(--surface);
  border: 1px solid var(--border);
}

[data-theme="newsprint"] .search-wrap input:focus {
  box-shadow: 0 0 0 3px rgba(43, 43, 43, 0.15);
}

[data-theme="newsprint"] .tweaks-panel,
[data-theme="newsprint"] .tweaks-toggle {
  background: var(--surface);
  border: 1px solid var(--border);
}

[data-theme="newsprint"] .colophon {
  border-top: 1px solid var(--border);
}

[data-theme="newsprint"] .event-body-inner p,
[data-theme="newsprint"] .event-body-inner li {
  color: var(--text-muted);
  line-height: 1.75;
}

[data-theme="newsprint"] .event-sources a::before {
  color: var(--accent);
}

[data-theme="newsprint"] mark {
  background: rgba(43, 43, 43, 0.12);
}

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