/* US Debt Timeline — Design System
   Inspired by America.gov + USWDS principles
   Light mode only. Public Sans body, Merriweather headings.
   Gold and red reserved for timeline markers.
*/

@import url('https://fonts.googleapis.com/css2?family=Merriweather:wght@400;700&family=Public+Sans:wght@400;500;600;700&display=swap');

:root {
  /* Core colors — light, professional, America.gov-inspired */
  --color-bg: #ffffff;
  --color-text: #000c1f;
  --color-text-muted: #3d4551;
  --color-border: #dfe1e2;
  --color-surface: #f8f9fa;
  --color-surface-raised: #ffffff;

  /* Accents — restrained, used sparingly */
  --color-primary: #005ea2;          /* USWDS primary blue — links, active states */
  --color-primary-hover: #1a4480;
  --color-gold: #ffbe2e;             /* Timeline gold markers */
  --color-gold-dark: #e5a000;
  --color-red: #d83933;              /* Timeline war/crisis markers */
  --color-red-dark: #b50909;
  --color-green: #00a91c;            /* Future / positive markers */

  /* Typography */
  --font-sans: "Public Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-serif: "Merriweather", Georgia, "Times New Roman", serif;

  /* Spacing & shape */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-pill: 9999px;
  --shadow-sm: 0 1px 2px rgba(0, 12, 31, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 12, 31, 0.08);
}

/* Base */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  font-size: 1.05rem;
}

/* Typography */
h1, h2, h3, .font-serif {
  font-family: var(--font-serif);
  font-weight: 400;
  line-height: 1.25;
  color: var(--color-text);
}
h1 { font-size: clamp(2.2rem, 5vw, 3.2rem); margin: 0 0 0.75rem; }
h2 { font-size: 1.45rem; margin: 0 0 0.35rem; }
p { margin: 0.5rem 0; }
a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Layout */
header {
  padding: 3rem 1.5rem 2rem;
  text-align: center;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
}
header p {
  color: var(--color-text-muted);
  max-width: 42rem;
  margin-inline: auto;
  font-size: 1.1rem;
}

/* Controls / filters */
.controls {
  display: flex;
  gap: 0.6rem;
  justify-content: center;
  flex-wrap: wrap;
  padding: 1rem 1rem;
  background: var(--color-surface);
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid var(--color-border);
}
button {
  font-family: var(--font-sans);
  background: var(--color-surface-raised);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  padding: 0.45rem 1.1rem;
  border-radius: var(--radius-pill);
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}
button:hover { border-color: var(--color-primary); color: var(--color-primary); }
button.active {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

/* Timeline */
.timeline {
  max-width: 860px;
  margin: 2.5rem auto 4rem;
  padding: 0 1.25rem;
  position: relative;
}
.timeline::before {
  content: "";
  position: absolute;
  left: 1.75rem;
  top: 0;
  bottom: 0;
  width: 3px;
  background: linear-gradient(to bottom, var(--color-gold), var(--color-primary), var(--color-red));
  border-radius: 2px;
}
.event {
  position: relative;
  margin-bottom: 1.75rem;
  padding-left: 4rem;
}
.event::before {
  content: "";
  position: absolute;
  left: 1.15rem;
  top: 1.35rem;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 3px solid var(--color-bg);
  box-shadow: var(--shadow-sm);
  z-index: 1;
}
.event.gold::before { background: var(--color-gold); }
.event.war::before { background: var(--color-red); }
.event.future::before { background: var(--color-green); }

/* Cards */
.card {
  background: var(--color-surface-raised);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s, border-color 0.2s, transform 0.15s;
}
.card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}
.date {
  color: var(--color-primary);
  font-weight: 600;
  font-size: 0.85rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}
.summary { color: var(--color-text-muted); margin-top: 0.4rem; }

/* Details / tabs */
.details {
  display: none;
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
}
.event.open .details { display: block; }
.tabs { display: flex; gap: 0.4rem; margin-bottom: 0.85rem; flex-wrap: wrap; }
.tab {
  background: transparent;
  border: 1px solid var(--color-border);
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
  font-weight: 500;
}
.tab.active {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}
.tab-content { display: none; }
.tab-content.active { display: block; }
.facts {
  background: var(--color-surface);
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  margin: 0.75rem 0 0;
  font-size: 0.92rem;
  border-left: 3px solid var(--color-gold);
}
.facts strong { color: var(--color-text); }

/* Footer */
footer {
  text-align: center;
  padding: 2.5rem 1.5rem;
  color: var(--color-text-muted);
  font-size: 0.88rem;
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
}

/* Responsive */
@media (max-width: 640px) {
  .timeline::before { left: 1.1rem; }
  .event { padding-left: 3.2rem; }
  .event::before { left: 0.55rem; }
  header { padding: 2rem 1rem 1.5rem; }
}


/* Brand / header icon */
.brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 0.5rem;
}
.brand .icon {
  width: 72px;
  height: 48px;
  flex-shrink: 0;
}
.brand h1 {
  margin: 0;
  font-size: clamp(2.4rem, 6vw, 4.2rem);
}
.subtitle {
  font-family: var(--font-sans);
  font-weight: 400;
  font-size: 1.4rem;
  color: var(--color-text-muted);
  margin: 0.25rem 0 1rem;
  letter-spacing: 0;
}
.alt-journey {
  margin-top: 1.25rem;
  font-size: 0.95rem;
  color: var(--color-text-muted);
}
.alt-journey a {
  color: var(--color-primary);
  font-weight: 500;
  text-decoration: none;
  border-bottom: 1px solid transparent;
}
.alt-journey a:hover {
  border-bottom-color: var(--color-primary);
}

/* Questions view */
.questions-header {
  max-width: 720px;
  margin: 2.5rem auto 1.5rem;
  padding: 0 1.25rem;
  text-align: center;
}
.questions {
  max-width: 720px;
  margin: 0 auto 4rem;
  padding: 0 1.25rem;
}
.q-card {
  background: var(--color-surface-raised);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  margin-bottom: 0.75rem;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.q-header {
  padding: 1.1rem 1.4rem;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 1.05rem;
}
.q-header::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--color-primary);
  font-weight: 300;
}
.q-card.open .q-header::after { content: "–"; }
.q-answer {
  display: none;
  padding: 0 1.4rem 1.2rem;
  color: var(--color-text-muted);
  border-top: 1px solid var(--color-border);
}
.q-card.open .q-answer { display: block; }
.q-answer p { margin: 0.75rem 0 0; }

/* View switching — force isolation */
#timeline-view,
#questions-view {
  display: block;
}
#questions-view {
  display: none;
}
#questions-view.active {
  display: block;
}
#timeline-view.hidden {
  display: none;
}

/* Brand — stack icon above title, centered */
.brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}
.brand .icon {
  width: 80px;
  height: 56px;
}
.brand h1 {
  margin: 0;
  text-align: center;
}

/* Questions cards — stronger card look */
.q-card {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 12px;
  margin-bottom: 0.75rem;
  box-shadow: 0 1px 3px rgba(0,12,31,0.06);
}
.q-header {
  padding: 1rem 1.25rem;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.q-answer {
  display: none;
  padding: 0 1.25rem 1rem;
  color: var(--color-text-muted);
  border-top: 1px solid var(--color-border);
}
.q-card.open .q-answer {
  display: block;
}