/* ============================================================
   USM CS Programme Explorer — Stylesheet
   Design: technical "ledger" aesthetic for a reference tool —
   monospace course codes as structural data, flat panels with
   hairline borders, a distinct accent colour per branch.
   ============================================================ */

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

:root {
  --font-sans: 'IBM Plex Sans', system-ui, -apple-system, sans-serif;
  --font-mono: 'IBM Plex Mono', ui-monospace, 'SFMono-Regular', Menlo, monospace;

  --bg: #F5F6F8;
  --bg-elevated: #FFFFFF;
  --panel-border: #DBDFE5;
  --text: #1B1F27;
  --text-muted: #5B6472;
  --text-faint: #8992A0;
  --accent-neutral: #3E5C76;
  --accent-neutral-bg: #EAF0F5;
  --shadow: 0 1px 2px rgba(20, 24, 32, 0.04);
  --shadow-lift: 0 8px 24px rgba(20, 24, 32, 0.12);
  --radius-sm: 4px;
  --radius-md: 7px;
  --track-common: #3E5C76;
  --track-branchcore: #6B7A8F;
  --track-ci: #1E8FA6;
  --track-ic: #7A5CC5;
  --track-se: #C97A2B;
  --track-capstone: #B4433C;
  --track-freemodule: #4E9153;
  --track-university: #8992A0;
  --track-elective: #C97A2B;
  --focus-ring: #3E5C76;
}

:root[data-theme="dark"] {
  --bg: #12151A;
  --bg-elevated: #1A1E26;
  --panel-border: #2C323C;
  --text: #E4E7EC;
  --text-muted: #9AA3B0;
  --text-faint: #6B7280;
  --accent-neutral: #7FA8CC;
  --accent-neutral-bg: #1E2733;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-lift: 0 12px 32px rgba(0, 0, 0, 0.5);
  --track-common: #7FA8CC;
  --track-branchcore: #8B96A5;
  --track-ci: #4FC3D9;
  --track-ic: #A48EE8;
  --track-se: #E0995A;
  --track-capstone: #E0736A;
  --track-freemodule: #6FBD75;
  --track-university: #8992A0;
  --track-elective: #E0995A;
  --focus-ring: #7FA8CC;
}

* { box-sizing: border-box; }
html {
  scroll-padding-top: env(safe-area-inset-top, 0px);
}
body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.5;
  padding-top: env(safe-area-inset-top, 0px);
  padding-bottom: env(safe-area-inset-bottom, 0px);
}

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

button {
  font-family: inherit;
  cursor: pointer;
}
button:focus-visible,
input:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--panel-border);
  padding: env(safe-area-inset-top, 0px) 0 0 0;
}

.header-inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.site-title {
  font-weight: 700;
  font-size: 17px;
  margin: 0;
  white-space: nowrap;
}
.site-title small {
  display: block;
  font-weight: 400;
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 1px;
}

.search-wrap {
  position: relative;
  flex: 1 1 260px;
  min-width: 180px;
}
#search-input {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-sm);
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 14px;
}
#search-results {
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  right: 0;
  background: var(--bg-elevated);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lift);
  max-height: 320px;
  overflow-y: auto;
  z-index: 40;
}
.search-result {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  text-align: left;
  padding: 9px 12px;
  border: none;
  border-bottom: 1px solid var(--panel-border);
  background: transparent;
  color: var(--text);
  font-size: 13.5px;
}
.search-result:last-child { border-bottom: none; }
.search-result:hover { background: var(--accent-neutral-bg); }
.search-result .course-name { flex: 1; }
.search-empty {
  padding: 12px;
  color: var(--text-muted);
  font-size: 13.5px;
}

.header-controls {
  display: flex;
  gap: 8px;
  flex-shrink: 0;
}
.icon-btn {
  border: 1px solid var(--panel-border);
  background: var(--bg-elevated);
  color: var(--text);
  padding: 7px 11px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  white-space: nowrap;
}
.icon-btn:hover { border-color: var(--accent-neutral); }

/* ---------- Tabs ---------- */

.tabs-wrap {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 20px;
  overflow-x: auto;
}
#tabs {
  display: flex;
  gap: 2px;
  border-bottom: 1px solid var(--panel-border);
}
.tab-btn {
  border: none;
  background: transparent;
  color: var(--text-muted);
  padding: 10px 16px;
  font-size: 13.5px;
  font-weight: 500;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
}
.tab-btn:hover { color: var(--text); }
.tab-btn.active {
  color: var(--text);
  border-bottom-color: var(--accent-neutral);
}

/* ---------- Main layout ---------- */

#app {
  max-width: 1180px;
  margin: 0 auto;
  padding: 24px 20px 64px;
}

.branch-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  flex-wrap: wrap;
  border-left: 4px solid var(--branch-accent, var(--accent-neutral));
  padding-left: 14px;
  margin-bottom: 20px;
}
.branch-header h2 {
  margin: 0 0 4px;
  font-size: 22px;
}
.ms-name {
  font-weight: 400;
  font-size: 14px;
  color: var(--text-muted);
  font-style: italic;
}
.programme-title {
  margin: 0;
  color: var(--text-muted);
  font-size: 13.5px;
}

.progress-widget {
  min-width: 200px;
  text-align: right;
}
.progress-ring-track {
  width: 200px;
  height: 6px;
  border-radius: 3px;
  background: var(--panel-border);
  overflow: hidden;
  margin-bottom: 5px;
}
.progress-ring-fill {
  height: 100%;
  background: var(--branch-accent, var(--accent-neutral));
  transition: width 0.3s ease;
}
.progress-text {
  font-size: 12px;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 14px;
  margin-bottom: 32px;
}
.info-card {
  background: var(--bg-elevated);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-md);
  padding: 16px 18px;
  box-shadow: var(--shadow);
}
.info-card h3 {
  margin: 0 0 10px;
  font-size: 13.5px;
  text-transform: none;
  color: var(--text);
  border-bottom: 1px solid var(--panel-border);
  padding-bottom: 8px;
}
.info-card p { margin: 0 0 8px; font-size: 13.5px; color: var(--text-muted); }
.info-card p:last-child { margin-bottom: 0; }

.not-specified {
  font-style: italic;
  color: var(--text-faint) !important;
}

.fine-note {
  font-size: 12.5px;
  color: var(--text-faint);
  margin: 6px 0 10px;
  line-height: 1.5;
}

.plain-list, .plo-list {
  margin: 0;
  padding-left: 18px;
  font-size: 13px;
  color: var(--text-muted);
}
.plain-list li, .plo-list li { margin-bottom: 6px; }
.plo-list { max-height: 220px; overflow-y: auto; }

/* ---------- Requirements table ---------- */

.req-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  margin-bottom: 4px;
}
.req-table th {
  text-align: left;
  font-weight: 600;
  color: var(--text-muted);
  padding: 5px 4px;
  border-bottom: 1px solid var(--panel-border);
  font-size: 11.5px;
}
.req-table td {
  padding: 5px 4px;
  border-bottom: 1px solid var(--panel-border);
}
.req-table td.num { text-align: right; font-family: var(--font-mono); }
.req-total td { color: var(--text-muted); }
.req-grand-total td {
  font-weight: 700;
  border-top: 2px solid var(--text);
  border-bottom: none;
}

.type-chip {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 10.5px;
  padding: 1px 6px;
  border-radius: 3px;
  background: var(--accent-neutral-bg);
  color: var(--accent-neutral);
  white-space: nowrap;
}

/* ---------- Elective pool ---------- */

.pool-list { list-style: none; margin: 0; padding: 0; }
.pool-row {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 0;
  border-bottom: 1px solid var(--panel-border);
  font-size: 13px;
}
.pool-row:last-child { border-bottom: none; }
.pool-row.is-done .course-name { text-decoration: line-through; color: var(--text-faint); }
.pool-note-flag {
  font-size: 10px;
  color: var(--track-elective);
  border: 1px solid var(--track-elective);
  border-radius: 3px;
  padding: 0 4px;
  cursor: help;
}

/* ---------- Roadmap ---------- */

.roadmap-heading {
  font-size: 16px;
  margin: 8px 0 10px;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 16px;
  margin-bottom: 14px;
  font-size: 11.5px;
  color: var(--text-muted);
}
.legend-item { display: flex; align-items: center; gap: 5px; }
.legend-dot {
  width: 9px; height: 9px; border-radius: 2px; display: inline-block; flex-shrink: 0;
}

.year-accordion {
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-md);
  margin-bottom: 10px;
  background: var(--bg-elevated);
  overflow: hidden;
}
.year-accordion > summary {
  padding: 12px 16px;
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.year-accordion > summary::-webkit-details-marker { display: none; }
.year-accordion > summary::after {
  content: '+';
  font-size: 16px;
  color: var(--text-muted);
  font-weight: 400;
}
.year-accordion[open] > summary::after { content: '−'; }
.year-accordion[open] > summary { border-bottom: 1px solid var(--panel-border); }

.year-body { padding: 4px 16px 12px; }

.sem-block { margin-top: 12px; }
.sem-heading {
  font-size: 12.5px;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: var(--text-muted);
  margin: 0 0 6px;
  display: flex;
  justify-content: space-between;
  font-weight: 600;
}
.sem-total { font-family: var(--font-mono); text-transform: none; letter-spacing: 0; font-weight: 400; }

.course-list { list-style: none; margin: 0; padding: 0; }
.course-row {
  border-bottom: 1px solid var(--panel-border);
}
.course-row:last-child { border-bottom: none; }
.course-row-main {
  width: 100%;
  display: grid;
  grid-template-columns: 20px 78px 1fr 52px 16px;
  align-items: center;
  gap: 10px;
  padding: 8px 2px;
  background: transparent;
  border: none;
  color: var(--text);
  text-align: left;
}
.course-row-main:hover { background: var(--accent-neutral-bg); }
.course-check { width: 15px; height: 15px; accent-color: var(--branch-accent, var(--accent-neutral)); }
.course-code {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-muted);
}
.course-name { font-size: 13.5px; }
.course-row.is-done .course-name { text-decoration: line-through; color: var(--text-faint); }
.course-credit {
  font-family: var(--font-mono);
  font-size: 12px;
  text-align: right;
  color: var(--text-muted);
}
.course-credit small { font-size: 9px; margin-left: 1px; }
.course-caret {
  color: var(--text-faint);
  transition: transform 0.15s ease;
  font-size: 15px;
}
.course-row-main[aria-expanded="true"] .course-caret { transform: rotate(90deg); }

.course-detail {
  padding: 4px 2px 14px 30px;
  font-size: 13px;
}
.detail-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 8px 16px;
  margin-bottom: 10px;
}
.detail-label {
  display: block;
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--text-faint);
  margin-bottom: 2px;
}
.detail-value { font-size: 13px; }
.detail-prereq, .detail-note {
  font-size: 12.5px;
  color: var(--text-muted);
  background: var(--accent-neutral-bg);
  border-radius: var(--radius-sm);
  padding: 8px 10px;
  margin: 0 0 8px;
}
.detail-note { background: transparent; border: 1px dashed var(--panel-border); }
.elective-note-input {
  width: 100%;
  max-width: 320px;
  padding: 6px 9px;
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-sm);
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 13px;
  margin-top: 3px;
}

.flash-highlight { animation: flash 1.6s ease; }
@keyframes flash {
  0%, 100% { background: transparent; }
  15% { background: var(--accent-neutral-bg); }
}

/* ---------- Track badges (colour-coded) ---------- */

.track-badge {
  display: inline-block;
  font-size: 11px;
  padding: 1px 7px;
  border-radius: 3px;
  color: #fff;
}
.track-common       { background: var(--track-common); }
.track-branchcore    { background: var(--track-branchcore); }
.track-ci-track       { background: var(--track-ci); }
.track-ic-track       { background: var(--track-ic); }
.track-se-track       { background: var(--track-se); }
.track-capstone      { background: var(--track-capstone); }
.track-freemodule    { background: var(--track-freemodule); }
.track-university    { background: var(--track-university); }
.track-elective      { background: var(--track-elective); }

.legend-dot.track-common      { background: var(--track-common); }
.legend-dot.track-branchcore  { background: var(--track-branchcore); }
.legend-dot.track-ci-track    { background: var(--track-ci); }
.legend-dot.track-ic-track    { background: var(--track-ic); }
.legend-dot.track-se-track    { background: var(--track-se); }
.legend-dot.track-capstone    { background: var(--track-capstone); }
.legend-dot.track-freemodule  { background: var(--track-freemodule); }
.legend-dot.track-university  { background: var(--track-university); }
.legend-dot.track-elective    { background: var(--track-elective); }

/* ---------- Compare view ---------- */

.compare-view h2 { margin-top: 0; }
.compare-view h3 {
  font-size: 14.5px;
  margin: 28px 0 8px;
  border-bottom: 1px solid var(--panel-border);
  padding-bottom: 6px;
}

.compare-req-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 14px;
  margin-bottom: 8px;
}
.compare-req-col {
  background: var(--bg-elevated);
  border: 1px solid var(--panel-border);
  border-left: 4px solid var(--branch-accent);
  border-radius: var(--radius-md);
  padding: 14px 16px;
}
.compare-req-col h4 { margin: 0 0 8px; font-size: 13.5px; }

.compare-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  margin-bottom: 6px;
}
.compare-table th {
  text-align: left;
  color: var(--text-muted);
  font-size: 11.5px;
  font-weight: 600;
  padding: 6px 8px;
  border-bottom: 1px solid var(--panel-border);
}
.compare-table td {
  padding: 6px 8px;
  border-bottom: 1px solid var(--panel-border);
}

.branch-pill {
  display: inline-block;
  font-size: 10.5px;
  font-family: var(--font-mono);
  padding: 1px 6px;
  border-radius: 3px;
  color: #fff;
  margin-right: 3px;
}
.branch-pill.branch-ci { background: var(--track-ci); }
.branch-pill.branch-ic { background: var(--track-ic); }
.branch-pill.branch-se { background: var(--track-se); }

.compare-unique-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin-top: 6px;
}
.compare-unique-col {
  border-left: 4px solid var(--branch-accent);
  padding-left: 12px;
}
.compare-unique-col h4 { font-size: 13px; margin: 0 0 6px; }

/* ---------- Responsive ---------- */

@media (max-width: 640px) {
  .header-inner { padding: 10px 14px; }
  .site-title { font-size: 15px; }
  .search-wrap { order: 3; flex: 1 1 100%; }
  #app { padding: 16px 14px 48px; }
  .course-row-main { grid-template-columns: 18px 62px 1fr 44px 14px; gap: 7px; }
  .progress-widget { text-align: left; }
  .progress-ring-track { width: 140px; }
  .branch-header { flex-direction: column; }
}

@media (max-width: 420px) {
  .course-code { font-size: 10.5px; }
  .course-name { font-size: 12.5px; }
}

/* ---------- Reduced motion ---------- */

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}