@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:opsz,wght@8..60,300;8..60,400;8..60,600;8..60,700&family=Inter:wght@400;500;600&display=swap');

/* ── Tokens ── */
:root {
  --ink:          #1a2234;
  --ink-soft:     #4a5568;
  --ink-muted:    #8492a6;
  --paper:        #f8f6f1;
  --paper-raised: #ffffff;
  --line:         #e4dfd6;
  --accent:       #2d4a7a;
  --accent-mid:   #3d6499;
  --accent-soft:  #eaf0f9;
  --gold:         #c9a84c;
  --gold-soft:    #fdf6e3;
  --online:       #2d7a5a;
  --online-soft:  #e8f5ef;
  --radius:       12px;
  --radius-sm:    8px;
}

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

body {
  background: var(--paper);
  color: var(--ink);
  font-family: 'Inter', system-ui, sans-serif;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
  font-family: 'Source Serif 4', Georgia, serif;
  color: var(--ink);
  line-height: 1.2;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 3px; }

.wrap { max-width: 820px; margin: 0 auto; padding: 0 28px; }

/* ── Nav ── */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(248,246,241,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav-wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 18px;
  padding-bottom: 18px;
  gap: 16px;
  flex-wrap: wrap;
}
.brand {
  font-family: 'Source Serif 4', serif;
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--ink);
  letter-spacing: -0.01em;
}
.site-header nav {
  display: flex;
  gap: 6px;
  align-items: center;
  flex-wrap: wrap;
}
.site-header nav a {
  color: var(--ink-soft);
  font-size: 0.88rem;
  font-weight: 500;
  padding: 6px 10px;
  border-radius: 6px;
  transition: background 0.15s, color 0.15s;
}
.site-header nav a:hover { background: var(--accent-soft); color: var(--accent); text-decoration: none; }
.site-header nav a.active { color: var(--accent); background: var(--accent-soft); }
.nav-cta {
  background: var(--accent) !important;
  color: #fff !important;
  padding: 6px 14px !important;
  border-radius: 100px !important;
}
.nav-cta:hover { background: var(--accent-mid) !important; text-decoration: none !important; }

/* ── Hero ── */
.hero {
  padding: 72px 0 56px;
  border-bottom: 1px solid var(--line);
}
.hero-wrap {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 48px;
  align-items: start;
}
.hero-eyebrow {
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--gold);
  margin-bottom: 10px;
}
.hero h1 {
  font-size: clamp(2.4rem, 6vw, 3.4rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--ink);
  margin-bottom: 6px;
}
.hero-sub {
  font-size: 0.92rem;
  color: var(--ink-muted);
  margin-bottom: 20px;
}
.hero-bio {
  font-size: 1rem;
  color: var(--ink-soft);
  max-width: 52ch;
  line-height: 1.7;
  margin-bottom: 28px;
}
.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
  padding: 10px 22px;
  border-radius: 100px;
  font-size: 0.9rem;
  font-weight: 600;
  transition: background 0.15s, transform 0.15s;
}
.btn-primary:hover { background: var(--accent-mid); transform: translateY(-1px); text-decoration: none; }
.btn-ghost {
  background: transparent;
  color: var(--accent);
  padding: 10px 22px;
  border-radius: 100px;
  font-size: 0.9rem;
  font-weight: 600;
  border: 1.5px solid var(--accent);
  transition: background 0.15s, transform 0.15s;
}
.btn-ghost:hover { background: var(--accent-soft); transform: translateY(-1px); text-decoration: none; }

/* stat stack */
.stat-stack {
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-width: 140px;
}
.stat-card {
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 20px;
  display: flex;
  flex-direction: column;
  gap: 2px;
  text-align: center;
}
.stat-num {
  font-family: 'Source Serif 4', serif;
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
}
.stat-label {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-muted);
}

/* ── Section commons ── */
.section { padding: 48px 0; }
.section-divider { border-top: 1px solid var(--line); }
.section-header {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 24px;
}
.section-header h2 { font-size: 1.4rem; }
.term-badge {
  font-family: 'Inter', sans-serif;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  background: var(--gold-soft);
  color: var(--gold);
  border: 1px solid #e8d5a0;
  padding: 3px 10px;
  border-radius: 100px;
}

/* ── Course cards ── */
.course-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}
.course-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 18px 20px;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s;
  color: var(--ink);
}
.course-card:hover {
  border-color: var(--accent);
  border-left-color: var(--gold);
  box-shadow: 0 4px 16px rgba(45,74,122,0.10);
  transform: translateY(-2px);
  text-decoration: none;
}
.card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.course-code {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.course-mode {
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  background: var(--accent-soft);
  color: var(--accent);
  padding: 2px 8px;
  border-radius: 100px;
}
.course-mode.online {
  background: var(--online-soft);
  color: var(--online);
}
.course-name {
  font-family: 'Source Serif 4', serif;
  font-size: 1.05rem;
  color: var(--ink);
  line-height: 1.3;
}
.course-time {
  font-size: 0.8rem;
  color: var(--ink-muted);
}
.all-link {
  display: inline-block;
  margin-top: 18px;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--accent);
}

/* ── Outreach cards ── */
.outreach-grid {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.outreach-card {
  display: flex;
  gap: 20px;
  align-items: flex-start;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 22px;
  color: var(--ink);
  transition: border-color 0.15s, box-shadow 0.15s;
}
.outreach-card:hover {
  border-color: var(--accent);
  box-shadow: 0 4px 16px rgba(45,74,122,0.08);
  text-decoration: none;
}
.outreach-icon {
  font-size: 1.6rem;
  color: var(--accent);
  font-family: 'Source Serif 4', serif;
  line-height: 1;
  min-width: 36px;
  text-align: center;
  margin-top: 2px;
}
.outreach-card h3 {
  font-size: 1rem;
  margin-bottom: 4px;
}
.outreach-card p {
  font-size: 0.88rem;
  color: var(--ink-soft);
  line-height: 1.5;
}

/* ── Contact ── */
.contact-section { padding-bottom: 64px; }
.contact-section h2 { font-size: 1.4rem; margin-bottom: 6px; }
.contact-sub {
  font-size: 0.92rem;
  color: var(--ink-soft);
  margin-bottom: 24px;
}
.contact-row {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.contact-item {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.95rem;
  color: var(--ink);
}
.contact-icon {
  font-size: 1.1rem;
  width: 32px;
  text-align: center;
  color: var(--accent);
}

/* ── Footer ── */
footer {
  border-top: 1px solid var(--line);
  padding: 24px 0;
  background: var(--paper-raised);
}
.footer-wrap {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 0.8rem;
  color: var(--ink-muted);
}

.topic-link-pending {
  background: var(--line);
  color: var(--ink-muted);
  cursor: default;
  pointer-events: none;
}

/* ── HSTA index ── */
.hsta-year-grid {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.hsta-year-card {
  display: flex;
  align-items: center;
  gap: 20px;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 20px 24px;
  color: var(--ink);
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s;
  text-decoration: none;
}
.hsta-year-card:hover {
  border-color: var(--accent);
  border-left-color: var(--gold);
  box-shadow: 0 4px 16px rgba(45,74,122,0.10);
  transform: translateY(-1px);
}
.hsta-year-card.current-year { border-left-color: var(--gold); }
.year-label {
  font-family: 'Source Serif 4', serif;
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--accent);
  min-width: 60px;
}
.year-status {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  padding: 3px 10px;
  border-radius: 100px;
  white-space: nowrap;
}
.year-status.past { background: var(--accent-soft); color: var(--accent); }
.year-status.upcoming { background: var(--gold-soft); color: #9a7020; border: 1px solid #e8d5a0; }
.year-topics {
  font-size: 0.88rem;
  color: var(--ink-soft);
  margin-left: 4px;
}

/* ── HSTA session page ── */
.section-note {
  font-size: 0.88rem;
  color: var(--ink-soft);
  margin: -12px 0 20px;
}
.topic-cards {
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.topic-card {
  display: flex;
  gap: 20px;
  align-items: flex-start;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px 24px;
}
.topic-icon {
  font-size: 1.8rem;
  line-height: 1;
  min-width: 36px;
  margin-top: 2px;
}
.topic-body h3 {
  font-size: 1.1rem;
  margin-bottom: 6px;
}
.topic-body p {
  font-size: 0.88rem;
  color: var(--ink-soft);
  margin-bottom: 14px;
  max-width: 52ch;
}
.topic-link {
  display: inline-block;
  background: var(--accent);
  color: #fff;
  font-size: 0.82rem;
  font-weight: 600;
  padding: 7px 16px;
  border-radius: 100px;
  margin-right: 10px;
  margin-bottom: 8px;
  transition: background 0.15s;
}
.topic-link:hover { background: var(--accent-mid); text-decoration: none; }
.resource-link {
  display: inline-block;
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 500;
  padding: 7px 0;
}

/* resource groups */
.resource-group { margin-bottom: 28px; }
.resource-group-title {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--ink-muted);
  margin-bottom: 8px;
}
.resource-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.resource-item {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  color: var(--ink);
  font-size: 0.88rem;
  transition: background 0.12s, border-color 0.12s;
}
.resource-item:hover { background: var(--accent-soft); border-color: var(--accent); text-decoration: none; }
.resource-platform {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  background: var(--accent-soft);
  color: var(--accent);
  padding: 2px 8px;
  border-radius: 100px;
  white-space: nowrap;
  min-width: 68px;
  text-align: center;
}
.arrow { margin-left: auto; color: var(--ink-muted); font-size: 0.85em; }
.official-badge {
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  background: #eaf5ea;
  color: #2d7a4a;
  padding: 1px 6px;
  border-radius: 4px;
  margin-left: 4px;
}
.yt-badge {
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  background: #fdecea;
  color: #c0392b;
  padding: 1px 6px;
  border-radius: 4px;
  margin-left: 4px;
}
.optional-badge {
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  background: var(--gold-soft);
  color: #9a7020;
  padding: 1px 6px;
  border-radius: 4px;
  margin-left: 4px;
}

/* year nav */
.year-nav {
  display: flex;
  justify-content: space-between;
  padding: 32px 0 56px;
  border-top: 1px solid var(--line);
  margin-top: 16px;
}
.year-nav a { font-size: 0.9rem; font-weight: 500; color: var(--accent); }

/* coming soon */
.coming-soon-box {
  display: flex;
  align-items: center;
  gap: 16px;
  background: var(--gold-soft);
  border: 1px solid #e8d5a0;
  border-radius: var(--radius);
  padding: 24px 28px;
  margin: 8px 0 32px;
  color: var(--ink-soft);
  font-size: 0.95rem;
}
.coming-icon { font-size: 1.6rem; }

@media (max-width: 640px) {
  .hsta-year-card { flex-wrap: wrap; gap: 8px; }
  .year-topics { flex-basis: 100%; margin-left: 0; }
  .topic-card { flex-direction: column; gap: 12px; }
}

/* ── Calculators ── */
.calc-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-top: 18px;
}
.calc-card {
  background: var(--accent-soft);
  border: 1px solid #c5d4ea;
  border-radius: var(--radius);
  padding: 16px 18px;
}
.calc-title {
  font-family: 'Source Serif 4', serif;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 4px;
}
.calc-desc {
  font-size: 0.78rem;
  color: var(--ink-soft);
  margin-bottom: 12px;
}
.calc-fields {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 12px;
}
.calc-fields label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: var(--ink);
  gap: 8px;
}
.calc-fields input {
  width: 90px;
  padding: 4px 8px;
  border: 1px solid var(--line);
  border-radius: 6px;
  font-size: 0.85rem;
  font-family: 'Inter', sans-serif;
  background: var(--paper-raised);
  color: var(--ink);
  text-align: right;
}
.calc-fields input:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}
.calc-btn {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 100px;
  padding: 7px 16px;
  font-size: 0.82rem;
  font-weight: 600;
  font-family: 'Inter', sans-serif;
  cursor: pointer;
  transition: background 0.15s;
  width: 100%;
}
.calc-btn:hover { background: var(--accent-mid); }
.calc-result {
  margin-top: 10px;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--accent);
  min-height: 1.4em;
  font-family: 'Source Serif 4', serif;
}

@media (max-width: 640px) {
  .calc-row { grid-template-columns: 1fr; }
}

/* ── Topics (course page) ── */
.topics { padding: 8px 0 40px; border-top: 1px solid var(--line); margin-top: 8px; padding-top: 36px; }
.topics h2 { font-size: 1.3rem; margin-bottom: 6px; }
.topics-sub { font-size: 0.85rem; color: var(--ink-soft); margin: 0 0 18px; }
.topic-list { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.topic-list li { border: 1px solid var(--line); border-radius: var(--radius-sm); background: var(--paper-raised); }
.topic-list a {
  display: flex; align-items: center; gap: 10px;
  padding: 12px 16px; color: var(--ink); font-size: 0.95rem;
  border-radius: var(--radius-sm); transition: background 0.15s;
}
.topic-list a:hover { background: var(--accent-soft); text-decoration: none; }
.topic-list a::after { content: '↗'; margin-left: auto; color: var(--accent); font-size: 0.85em; }

/* ── Archive (course page) ── */
.archive { padding: 36px 0 56px; border-top: 1px solid var(--line); margin-top: 8px; }
.archive h2 { font-size: 1.3rem; margin-bottom: 16px; display: flex; align-items: baseline; gap: 10px; }
.archive-list { list-style: none; }
.archive-list li { padding: 6px 0; }
.archive-list a { color: var(--ink-soft); font-size: 0.92rem; }

/* ── Back link ── */
.back-link { display: inline-block; margin-top: 28px; font-size: 0.9rem; color: var(--ink-soft); }

/* ── Mobile ── */
@media (max-width: 640px) {
  .hero-wrap { grid-template-columns: 1fr; }
  .stat-stack { flex-direction: row; flex-wrap: wrap; min-width: unset; }
  .stat-card { flex: 1; min-width: 100px; }
  .course-grid { grid-template-columns: 1fr; }
  .nav-wrap { gap: 10px; }
  .site-header nav a { padding: 5px 8px; font-size: 0.82rem; }
  .hero { padding: 48px 0 40px; }
  .footer-wrap { flex-direction: column; text-align: center; }
}