/* Site-wide visual language: a study notebook with clear, functional controls. */
:root,
[data-theme="light"] {
  --primary: #276650;
  --primary-hover: #1b503e;
  --primary-light: #e4eee7;
  --primary-glow: transparent;
  --success: #276650;
  --success-bg: #e4eee7;
  --success-border: #a8c6b5;
  --danger: #a34433;
  --danger-bg: #f8eae5;
  --danger-border: #e4b5a7;
  --warning: #88632d;
  --warning-bg: #f8f0df;
  --warning-border: #ddcb9d;
  --info: #276650;
  --info-bg: #e4eee7;
  --bg-main: #f3f4ed;
  --bg-card: #fffefa;
  --bg-card-hover: #f7f8f2;
  --bg-surface: #ecefe9;
  --border-color: #d4ddd4;
  --border-light: #e0e6df;
  --text-main: #1b302e;
  --text-muted: #50645e;
  --text-subtle: #61756d;
  --shadow-sm: none;
  --shadow-md: none;
  --shadow-lg: none;
  --shadow-card: none;
  --radius-sm: 3px;
  --radius-md: 3px;
  --radius-lg: 4px;
  --radius-xl: 4px;
  --button-text: #ffffff;
}
[data-theme="dark"] {
  --primary: #a6d9bd;
  --primary-hover: #c6ecd5;
  --primary-light: #2a443a;
  --primary-glow: transparent;
  --success: #a6d9bd;
  --success-bg: #254338;
  --success-border: #416b58;
  --danger: #f2b29f;
  --danger-bg: #46342f;
  --danger-border: #80564d;
  --warning: #e5c995;
  --warning-bg: #453d2f;
  --warning-border: #746044;
  --info: #a6d9bd;
  --info-bg: #254338;
  --bg-main: #152226;
  --bg-card: #1d2d30;
  --bg-card-hover: #26373a;
  --bg-surface: #253639;
  --border-color: #3c5150;
  --border-light: #354a48;
  --text-main: #ecf4ec;
  --text-muted: #b7c8c0;
  --text-subtle: #9db1a8;
  --shadow-sm: none;
  --shadow-md: none;
  --shadow-lg: none;
  --shadow-card: none;
  --radius-sm: 3px;
  --radius-md: 3px;
  --radius-lg: 4px;
  --radius-xl: 4px;
  --button-text: #14261f;
}

body { font-family: "Segoe UI", Arial, sans-serif; line-height: 1.55; transition: none; }
:where(button, a, input, select, summary):focus-visible {
  outline: 3px solid #b47f3f;
  outline-offset: 3px;
}
.view-panel, .explanation-box, .modal-box { animation: none; }
.site-header { background: var(--bg-card); }
.header-container {
  max-width: 1240px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  padding: 1rem 1.5rem 0;
  gap: .25rem 1rem;
}
.brand { grid-column: 1; width: fit-content; }
.brand-icon {
  width: 38px;
  height: 38px;
  background: var(--text-main);
  color: var(--bg-card);
  border-radius: 2px;
  box-shadow: none;
  font: 700 .8rem Georgia, Cambria, serif;
  letter-spacing: -.06em;
}
.brand-text h1 { font: 600 1.12rem/1.2 Georgia, Cambria, serif; letter-spacing: -.025em; }
.brand-text p { font-size: .72rem; }
.badge-cert, .badge-tag, .badge-klevel, .glossary-acronym {
  background: var(--bg-surface);
  color: var(--text-muted);
  border: 1px solid var(--border-color);
  border-radius: 2px;
  letter-spacing: .02em;
}
.badge-cert { font: 700 .66rem "Segoe UI", Arial, sans-serif; text-transform: none; }
.header-actions { grid-column: 2; grid-row: 1; }
.portfolio-link {
  color: var(--text-muted);
  font-size: .79rem;
  font-weight: 650;
  text-decoration: underline;
  text-underline-offset: 4px;
  margin-right: .5rem;
}
.portfolio-link:hover { color: var(--primary); }
.theme-toggle-btn {
  width: auto;
  height: auto;
  min-height: 34px;
  padding: .43rem .7rem;
  background: transparent;
  border-color: var(--border-color);
  font-size: .75rem;
  font-weight: 650;
}
.main-nav {
  grid-column: 1 / -1;
  grid-row: 2;
  flex-wrap: nowrap;
  gap: 1.35rem;
  min-width: 0;
  overflow-x: auto;
  margin-top: .7rem;
  scrollbar-width: thin;
}
.nav-btn {
  padding: .7rem 0 .8rem;
  color: var(--text-muted);
  border-radius: 0;
  border-bottom: 2px solid transparent;
  font-size: .79rem;
  font-weight: 650;
  transition: color .15s ease, border-color .15s ease;
}
.nav-btn:hover { background: transparent; color: var(--text-main); }
.nav-btn.active {
  color: var(--primary);
  background: transparent;
  border-bottom-color: var(--primary);
  box-shadow: none;
}
.main-content { max-width: 1240px; padding: 2rem 1.5rem 3rem; }
.page-title { font: 400 clamp(1.9rem, 3vw, 2.65rem)/1.16 Georgia, Cambria, serif; letter-spacing: -.045em; }
.page-subtitle { max-width: 760px; line-height: 1.6; margin-top: .5rem; }
.page-title-row { margin-bottom: 1.6rem; }
.hero-banner,
[data-theme="light"] .hero-banner {
  background: var(--bg-card) !important;
  background-size: auto !important;
  border: 1px solid var(--border-color) !important;
  border-top: 4px solid var(--primary) !important;
  border-radius: 3px;
  box-shadow: none !important;
  padding: clamp(1.5rem, 4vw, 3rem);
}
.hero-banner::after { display: none; }
.hero-content { max-width: 960px; }
.hero-content h2,
[data-theme="light"] .hero-content h2 {
  max-width: 850px;
  font: 400 clamp(2.55rem, 5vw, 4.55rem)/1.06 Georgia, Cambria, serif;
  letter-spacing: -.06em;
  color: var(--text-main) !important;
  text-shadow: none !important;
  margin: 0 0 1rem;
}
.hero-content p,
[data-theme="light"] .hero-content p {
  max-width: 750px;
  color: var(--text-muted) !important;
  text-shadow: none !important;
  font: 400 1rem/1.7 "Segoe UI", Arial, sans-serif !important;
}
.hero-content .hero-eyebrow,
[data-theme="light"] .hero-content .hero-eyebrow {
  color: var(--primary) !important;
  font: 750 .69rem/1.4 "Segoe UI", Arial, sans-serif !important;
  letter-spacing: .14em;
  margin-bottom: 1rem;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: .65rem; margin: 1.4rem 0 0; }
.hero-stats {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0;
  border-top: 1px solid var(--border-color);
  margin-top: 2.4rem;
}
.hero-banner .stat-chip,
[data-theme="light"] .hero-banner .stat-chip {
  display: block;
  padding: 1.15rem 1rem 0 0;
  background: transparent !important;
  border: 0 !important;
  border-radius: 0;
  color: var(--text-main) !important;
  box-shadow: none !important;
  backdrop-filter: none;
}
.hero-banner .stat-chip + .stat-chip { border-left: 1px solid var(--border-light) !important; padding-left: 1.2rem !important; }
.hero-banner .stat-info .stat-value,
[data-theme="light"] .hero-banner .stat-info .stat-value {
  color: var(--text-main) !important;
  text-shadow: none !important;
  font: 400 clamp(1.3rem, 2vw, 1.7rem)/1.2 Georgia, Cambria, serif;
  letter-spacing: -.03em;
}
.hero-banner .stat-info .stat-label,
[data-theme="light"] .hero-banner .stat-info .stat-label {
  color: var(--text-muted) !important;
  font-size: .7rem;
  letter-spacing: .02em;
  margin-top: .3rem;
}
.dash-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1px; background: var(--border-color); border: 1px solid var(--border-color); }
.dash-card {
  border: 0;
  border-radius: 0;
  padding: 1.5rem;
  box-shadow: none;
  min-width: 0;
  transition: background-color .15s ease;
}
.dash-card:hover { transform: none; background: var(--bg-card-hover); border-color: transparent; box-shadow: none; }
.dash-card-header { display: block; margin-bottom: 1rem; }
.dash-card-icon {
  width: auto;
  height: auto;
  justify-content: flex-start;
  margin-bottom: .9rem;
  background: transparent;
  color: var(--primary);
  font: 700 .72rem ui-monospace, Consolas, monospace;
  letter-spacing: .08em;
}
.dash-card-title { font: 400 1.45rem/1.2 Georgia, Cambria, serif; letter-spacing: -.03em; margin-bottom: .6rem; }
.dash-card-desc { font-size: .87rem; line-height: 1.6; }
.dash-card-footer { gap: .8rem; flex-wrap: wrap; border-top: 1px solid var(--border-light); padding-top: 1rem; }
.dash-card-badge { font-size: .7rem; color: var(--text-muted); }
.btn { border-radius: 3px; font-size: .83rem; box-shadow: none; transition: background-color .15s ease, border-color .15s ease; }
.btn-primary { background: var(--primary); color: var(--button-text); box-shadow: none; }
.btn-primary:hover { background: var(--primary-hover); transform: none; }
.btn-secondary { background: var(--bg-card); color: var(--text-main); }
.btn-success { background: var(--success-bg); color: var(--text-main); border: 1px solid var(--success-border); }
.btn-danger { background: var(--danger-bg); color: var(--text-main); border: 1px solid var(--danger-border); }
.btn-warning { background: var(--warning-bg); color: var(--text-main); border: 1px solid var(--warning-border); }
.btn:disabled { opacity: .48; cursor: not-allowed; }
.exam-summary-box { border-radius: 3px; box-shadow: none; gap: 0; }
.summary-item { padding: .55rem 1.2rem .55rem 0; }
.summary-item h4 { font-size: .67rem; color: var(--text-muted); }
.summary-item p { font: 400 1rem/1.35 Georgia, Cambria, serif; }
.chapter-sidebar, .chapter-content-pane, .practice-controls, .question-card, .glossary-card, .exam-header-bar, .exam-nav-panel { border-radius: 3px; box-shadow: none; }
.chapter-sidebar-title, .exam-nav-title { font-size: .7rem; letter-spacing: .11em; }
.chapter-nav-item { padding: 0; border-radius: 2px; font-weight: 500; }
.chapter-nav-trigger { display: grid; gap: .1rem; width: 100%; padding: .65rem .85rem; text-align: left; border: 0; background: transparent; color: inherit; cursor: pointer; font: inherit; }
.chapter-nav-info { display: grid; gap: .16rem; }
.chapter-nav-name { line-height: 1.35; }
.chapter-nav-meta { font-size: .72rem; color: var(--text-subtle); }
.chapter-nav-item.active { background: var(--primary-light); color: var(--text-main); border-color: var(--border-color); }
.chapter-nav-item.active .chapter-nav-num { color: var(--primary); }
.chapter-content-pane { padding: clamp(1.35rem, 3vw, 2.4rem); }
.chapter-badge-row { display: flex; flex-wrap: wrap; gap: .4rem; margin-bottom: 1.1rem; }
.chapter-main-title { font: 400 clamp(2.2rem, 4vw, 3.6rem)/1.08 Georgia, Cambria, serif; letter-spacing: -.05em; }
.chapter-main-subtitle { font-size: 1.1rem; margin-top: .6rem; color: var(--text-muted); }
.chapter-overview-text { margin-top: 1.1rem; max-width: 770px; line-height: 1.75; }
.chapter-hero { border-bottom: 1px solid var(--border-color); padding-bottom: 1.5rem; margin-bottom: 1.7rem; }
.learning-objectives-box { margin-top: 1.5rem; background: var(--bg-surface); border-left: 3px solid var(--primary); border-radius: 0; }
.learning-objectives-box h4, .cheatsheet-key, .question-num, .explanation-title { color: var(--primary); }
.chapter-section-block { margin: 0 0 2rem; }
.chapter-section-block .section-title { font: 400 1.7rem/1.25 Georgia, Cambria, serif; letter-spacing: -.03em; margin-bottom: .7rem; }
.markdown-body { line-height: 1.8; overflow-wrap: anywhere; }
.markdown-body h2, .markdown-body h3, .markdown-body h4 { font: 400 1.32rem/1.35 Georgia, Cambria, serif; margin: 1.3rem 0 .5rem; }
.markdown-body li { margin-left: 1.4rem; padding-left: .3rem; }
.markdown-body code { font: .86em ui-monospace, Consolas, monospace; background: var(--bg-surface); padding: .1em .3em; }
.markdown-body pre { max-width: 100%; overflow-x: auto; background: var(--bg-surface); padding: 1rem; }
.cheat-sheet-box { border-top: 1px solid var(--border-color); padding-top: 1.3rem; }
.cheat-sheet-box h4 { font: 400 1.55rem Georgia, Cambria, serif; margin-bottom: .8rem; }
.cheat-sheet-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: .55rem; }
.cheat-item { border: 1px solid var(--border-color); padding: .75rem; display: grid; gap: .3rem; }
.cheat-key { color: var(--primary); font-size: .75rem; font-weight: 700; }
.cheat-val { color: var(--text-main); font-size: .86rem; }
.pitfalls-box { background: var(--warning-bg); border-left: 3px solid var(--warning); border-radius: 0; }
.pitfalls-box h4 { color: var(--text-main); }
.filter-select, .search-input { border-radius: 3px; outline: initial; background: var(--bg-card); }
.card-perspective-stage { perspective: none; min-height: 340px; }
.flashcard { transform: none !important; transform-style: flat; transition: none; min-height: 340px; }
.card-face {
  position: relative;
  top: auto;
  left: auto;
  min-height: 340px;
  height: auto;
  backface-visibility: visible;
  transform: none;
  box-shadow: none;
  background: var(--bg-card);
  border-radius: 3px;
  padding: clamp(1.3rem, 4vw, 2.25rem);
}
.flashcard .card-back { display: none; }
.flashcard.flipped .card-front, .flashcard.is-flipped .card-front { display: none; }
.flashcard.flipped .card-back, .flashcard.is-flipped .card-back { display: flex; }
.card-chapter-tag { background: var(--primary-light); color: var(--text-main); border-radius: 2px; }
.card-side-label { font-size: .75rem; color: var(--text-muted); }
.card-main-content { margin: auto 0; }
.card-prompt { font: 400 clamp(1.4rem, 3vw, 2rem)/1.35 Georgia, Cambria, serif; }
.card-answer { font-size: 1rem; line-height: 1.7; }
.deck-progress-fill { background: var(--primary); }
.flashcard-actions { flex-wrap: wrap; gap: .5rem; }
.option-item { border-radius: 3px; background: var(--bg-card); }
.option-item:hover:not(.locked) { transform: none; background: var(--bg-card-hover); }
.option-item.selected { border-color: var(--primary); background: var(--primary-light); }
.option-item.correct { background: var(--success-bg) !important; border-color: var(--success-border) !important; }
.option-item.incorrect { background: var(--danger-bg) !important; border-color: var(--danger-border) !important; }
.option-item.correct .option-letter { background: var(--success) !important; border-color: var(--success) !important; color: var(--button-text) !important; }
.option-item.incorrect .option-letter { background: var(--danger) !important; border-color: var(--danger) !important; color: var(--bg-card) !important; }
.explanation-box { border-radius: 2px; }
.explanation-title { gap: .7rem; flex-wrap: wrap; }
.exam-setup-kicker { margin-bottom: .8rem; color: var(--primary); font-size: .7rem; font-weight: 750; letter-spacing: .13em; }
.exam-setup-title { font: 400 clamp(2.2rem, 4vw, 3.2rem)/1.12 Georgia, Cambria, serif; letter-spacing: -.045em; margin-bottom: .75rem; }
.exam-mode-card { border-width: 1px; background: var(--bg-card); border-radius: 3px; color: var(--text-main); font: inherit; }
.exam-mode-card.selected { background: var(--primary-light); border-color: var(--primary); }
.exam-mode-desc { display: block; }
.exam-timer { background: var(--bg-surface); color: var(--text-main); border-color: var(--border-color); border-radius: 3px; }
.exam-timer.warning { color: var(--danger); background: var(--danger-bg); animation: none; }
.exam-grid-cell.current { border-color: var(--primary); box-shadow: inset 0 0 0 1px var(--primary); }
.exam-grid-cell.flagged::after { background: var(--warning); }
.result-hero-card { text-align: center; border: 1px solid var(--border-color); }
.result-badge { border: 1px solid var(--border-color); border-radius: 2px; padding: .3rem .7rem; font-size: .74rem; letter-spacing: .06em; margin: 0 0 1rem; }
.result-badge.pass { color: var(--primary); background: var(--primary-light); }
.result-badge.fail { color: var(--danger); background: var(--danger-bg); }
.result-score-large { font: 400 clamp(2.8rem, 6vw, 4.5rem)/1 Georgia, Cambria, serif; letter-spacing: -.06em; }
.result-pct-large { color: var(--text-muted); font-size: 1.4rem; margin-top: .4rem; }
.result-feedback-text { color: var(--text-muted); max-width: 630px; margin: 1rem auto; }
.result-breakdown-row { display: grid; grid-template-columns: minmax(120px, 1fr) minmax(100px, 1fr) auto; gap: .9rem; align-items: center; padding: .65rem 0; border-top: 1px solid var(--border-light); font-size: .85rem; }
.perf-bar-wrap { background: var(--bg-surface); height: 7px; }
.perf-bar-fill.high { background: var(--primary); }
.perf-bar-fill.medium { background: var(--warning); }
.perf-bar-fill.low { background: var(--danger); }
.review-correct { border-left: 3px solid var(--success); }
.review-incorrect { border-left: 3px solid var(--danger); }
.glossary-card-header { display: flex; justify-content: space-between; gap: .6rem; align-items: flex-start; margin-bottom: .6rem; }
.glossary-badge { font-size: .69rem; font-weight: 700; padding: .18rem .4rem; border: 1px solid var(--border-color); color: var(--primary); }
.glossary-chapter-tag { margin-top: .9rem; padding-top: .7rem; border-top: 1px solid var(--border-light); color: var(--text-muted); font-size: .73rem; }
.site-footer { text-align: left; padding: 1.5rem max(1.5rem, calc((100% - 1192px) / 2)); }
.footer-subline { font-size: .76rem; margin-top: .25rem; }
.modal-overlay { backdrop-filter: none; background: rgba(8, 20, 20, .62); }
.lab-hero::before { display: none; }
.lab-hero { border-bottom-width: 3px; }
@media (max-width: 900px) {
  .dash-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .hero-stats { grid-template-columns: repeat(2, minmax(0, 1fr)); row-gap: 1rem; }
  .stat-chip:nth-child(3) { border-left: 0 !important; padding-left: 0 !important; }
}
@media (max-width: 620px) {
  .header-container { padding: .8rem 1rem 0; gap: .5rem; }
  .brand-text h1 { font-size: 1rem; }
  .brand-text p { font-size: .66rem; }
  .portfolio-link { display: none; }
  .main-nav { gap: 1.1rem; margin-top: .35rem; }
  .main-content { padding: 1.25rem 1rem 2rem; }
  .hero-banner { margin-bottom: 1rem; }
  .hero-content h2 { font-size: 2.55rem; }
  .dash-grid { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .hero-banner .stat-chip { padding-top: .8rem !important; }
  .hero-banner .stat-info .stat-value { font-size: 1.2rem; }
  .result-breakdown-row { grid-template-columns: minmax(0, 1fr) auto; }
  .perf-bar-wrap { grid-column: 1 / -1; grid-row: 2; }
  .flashcard-actions .btn { flex: 1 1 42%; }
  .flashcard-actions .btn-primary { flex-basis: 100%; order: -1; }
  .site-footer { padding: 1.3rem 1rem; }
}
@media (max-width: 390px) {
  .brand-text p, .badge-cert { display: none; }
  .theme-toggle-btn { font-size: .68rem; padding: .38rem .55rem; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: .01ms !important; transition-duration: .01ms !important; }
}