:root {
  --bg: #f6f5f2;
  --bg-soft: #fbfaf8;
  --surface: rgba(255, 255, 255, 0.88);
  --surface-strong: #ffffff;
  --surface-soft: #f1f0eb;
  --surface-muted: rgba(255, 255, 255, 0.58);
  --border: rgba(17, 24, 39, 0.1);
  --border-strong: rgba(17, 24, 39, 0.16);
  --text: #111827;
  --text-soft: #4b5563;
  --text-faint: #6b7280;
  --primary: #234764;
  --primary-strong: #18324a;
  --primary-contrast: #ffffff;
  --primary-soft: rgba(35, 71, 100, 0.08);
  --success: #146356;
  --success-soft: rgba(20, 99, 86, 0.1);
  --danger: #b42318;
  --danger-soft: rgba(180, 35, 24, 0.08);
  --shadow-sm: 0 1px 2px rgba(17, 24, 39, 0.03), 0 8px 24px rgba(17, 24, 39, 0.04);
  --shadow-md: 0 10px 30px rgba(17, 24, 39, 0.045);
  --shadow-lg: 0 20px 48px rgba(17, 24, 39, 0.06);
  --radius-sm: 12px;
  --radius-md: 20px;
  --radius-lg: 28px;
  --radius-pill: 999px;
  --container: 1120px;
  --narrow: 760px;
  --header-h: 74px;
  --bg-gradient: rgba(255, 255, 255, 0.7);
  --primary-glow: rgba(35, 71, 100, 0.08);
  --focus-ring: rgba(35, 71, 100, 0.24);
  --header-bg: rgba(246, 245, 242, 0.84);
  --border-muted: rgba(17, 24, 39, 0.08);
  --surface-tint: rgba(255, 255, 255, 0.92);
  --surface-tint-strong: rgba(255, 255, 255, 0.96);
  --surface-subtle: rgba(241, 240, 235, 0.84);
  --surface-section: rgba(255, 255, 255, 0.56);
  --primary-border-soft: rgba(35, 71, 100, 0.22);
  --muted-faint: rgba(107, 114, 128, 0.7);
  --progress-end: #5f7c95;
  --option-hover-border: rgba(35, 71, 100, 0.28);
  --success-border: rgba(20, 99, 86, 0.28);
  --danger-border: rgba(180, 35, 24, 0.28);
  --transition: 180ms ease;
}

html[data-theme="dark"] {
  --bg: #0c1117;
  --bg-soft: #0f1620;
  --surface: rgba(15, 23, 35, 0.76);
  --surface-strong: #111a26;
  --surface-soft: #162130;
  --surface-muted: rgba(15, 23, 35, 0.58);
  --border: rgba(168, 182, 201, 0.16);
  --border-strong: rgba(168, 182, 201, 0.28);
  --text: #f2f5fa;
  --text-soft: #c6d0dc;
  --text-faint: #94a3b8;
  --primary: #90afcb;
  --primary-strong: #a9c3dd;
  --primary-contrast: #09111a;
  --primary-soft: rgba(144, 175, 203, 0.16);
  --success: #7fcab8;
  --success-soft: rgba(127, 202, 184, 0.16);
  --danger: #e8a39d;
  --danger-soft: rgba(232, 163, 157, 0.15);
  --shadow-sm: none;
  --shadow-md: none;
  --shadow-lg: none;
  --bg-gradient: rgba(13, 17, 23, 0.74);
  --primary-glow: rgba(159, 192, 223, 0.12);
  --focus-ring: rgba(159, 192, 223, 0.3);
  --header-bg: rgba(12, 17, 23, 0.9);
  --border-muted: rgba(168, 182, 201, 0.12);
  --surface-tint: rgba(17, 26, 38, 0.94);
  --surface-tint-strong: rgba(17, 26, 38, 0.98);
  --surface-subtle: rgba(24, 34, 49, 0.95);
  --surface-section: rgba(15, 23, 35, 0.62);
  --primary-border-soft: rgba(144, 175, 203, 0.26);
  --muted-faint: rgba(148, 163, 184, 0.72);
  --progress-end: #d8e6f3;
  --option-hover-border: rgba(144, 175, 203, 0.48);
  --success-border: rgba(127, 202, 184, 0.44);
  --danger-border: rgba(232, 163, 157, 0.42);
}

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

html {
  scroll-behavior: smooth;
  color-scheme: light;
}

html[data-theme="dark"] {
  color-scheme: dark;
}

body {
  margin: 0;
  min-width: 320px;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    linear-gradient(180deg, var(--bg-gradient) 0%, transparent 32%),
    var(--bg);
  color: var(--text);
  font-size: 16px;
  line-height: 1.65;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(circle at top center, var(--primary-glow) 0, transparent 32rem);
  opacity: 0.9;
}

img,
svg {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

button,
input,
select {
  font: inherit;
}

button {
  cursor: pointer;
}

p,
ul,
ol {
  margin-top: 0;
}

.sr-only,
.skip-link:not(:focus) {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  overflow: hidden;
  white-space: nowrap;
  clip-path: inset(50%);
  border: 0;
  padding: 0;
}

.skip-link:focus {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 1000;
  background: var(--text);
  color: var(--bg);
  padding: 0.8rem 1rem;
  border-radius: 14px;
}

:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 3px;
}

main,
.site-header,
.site-footer {
  position: relative;
  z-index: 1;
}

.container {
  width: min(100% - 2rem, var(--container));
  margin-inline: auto;
}

.container.narrow,
.narrow {
  width: min(100% - 2rem, var(--narrow));
  margin-inline: auto;
}

.center {
  text-align: center;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: saturate(1.2) blur(18px);
  background: var(--header-bg);
  border-bottom: 1px solid var(--border-muted);
}

.header-shell {
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  min-width: 0;
}


.brand-mark {
  width: 2.75rem;
  height: 2.75rem;
  display: block;
  flex: 0 0 auto;
  border-radius: 14px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.brand-mark img {
  width: 100%;
  height: 100%;
  display: block;
}


.brand-text {
  display: flex;
  flex-direction: column;
  gap: 0.06rem;
  min-width: 0;
}

.brand-text strong {
  font-size: 1rem;
  line-height: 1.1;
  letter-spacing: -0.025em;
}

.brand-text span {
  color: var(--text-faint);
  font-size: 0.82rem;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.theme-toggle,
.nav-toggle {
  min-height: 2.9rem;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--surface-strong);
  color: var(--text);
  transition: background-color var(--transition), border-color var(--transition), transform var(--transition);
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0 0.95rem;
  font-weight: 650;
}

.theme-toggle:hover,
.theme-toggle:focus-visible,
.nav-toggle:hover,
.nav-toggle:focus-visible {
  transform: translateY(-1px);
  background: var(--surface-soft);
  border-color: var(--border-strong);
}

.theme-toggle-icon {
  width: 1rem;
  text-align: center;
  font-size: 1rem;
}

.theme-toggle-text {
  color: var(--text-soft);
  font-size: 0.94rem;
}

.nav-toggle {
  display: none;
  width: 2.9rem;
  padding: 0;
  align-items: center;
  justify-content: center;
  gap: 0.23rem;
  flex-direction: column;
}

.nav-toggle span:not(.sr-only) {
  display: block;
  width: 1.05rem;
  height: 2px;
  background: currentColor;
  border-radius: 999px;
  transition: transform var(--transition), opacity var(--transition);
}

.nav-open .nav-toggle span:nth-child(2) {
  transform: translateY(6px) rotate(45deg);
}

.nav-open .nav-toggle span:nth-child(3) {
  opacity: 0;
}

.nav-open .nav-toggle span:nth-child(4) {
  transform: translateY(-6px) rotate(-45deg);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 0.2rem;
  justify-content: flex-end;
  flex-wrap: wrap;
}

.nav-link {
  padding: 0.65rem 0.9rem;
  border-radius: 999px;
  color: var(--text-soft);
  font-size: 0.95rem;
  font-weight: 650;
  transition: color var(--transition), background-color var(--transition);
}

.nav-link:hover,
.nav-link:focus-visible,
.nav-link.active {
  color: var(--text);
  background: var(--surface-subtle);
}

main {
  padding-bottom: 4rem;
}

.hero,
.page-hero {
  padding: 4.6rem 0 2.1rem;
}

.hero-home {
  padding-top: 5rem;
}

.hero-grid,
.topic-hero-grid,
.grid-2,
.progress-layout,
.cta-panel,
.footer-grid {
  display: grid;
  gap: 1.25rem;
}

.hero-grid {
  grid-template-columns: minmax(0, 1.2fr) minmax(300px, 0.8fr);
  align-items: start;
}

.topic-hero-grid {
  grid-template-columns: minmax(0, 1fr) minmax(280px, 0.42fr);
  align-items: start;
}

.grid-2,
.progress-layout {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.hero-copy {
  padding: 0;
  background: transparent;
  border: 0;
  box-shadow: none;
  max-width: 44rem;
}

.hero-panel-card,
.panel-shell,
.info-card,
.topic-card,
.sample-question,
.step-card,
.benefit-card,
.stat-card,
.quiz-card,
.empty-state,
.cta-panel,
.faq-item,
.error-item,
.topic-progress-item,
.result-tile {
  background: var(--surface);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  border-radius: var(--radius-md);
}

.hero-panel-card {
  padding: 1.35rem;
  min-height: 100%;
  background: var(--surface-tint);
}

.eyebrow,
.mini-label {
  margin-bottom: 0.75rem;
  color: var(--primary);
  font-weight: 700;
  letter-spacing: 0.01em;
  font-size: 0.91rem;
}

.mini-label {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.76rem;
  color: var(--text-faint);
}

h1,
h2,
h3 {
  margin-top: 0;
  line-height: 1.08;
  letter-spacing: -0.035em;
}

h1 {
  font-size: clamp(2.4rem, 6vw, 4.8rem);
  margin-bottom: 1rem;
  max-width: 12ch;
}

.page-hero h1,
.page-hero-topic h1 {
  font-size: clamp(2rem, 4.4vw, 3.2rem);
  max-width: 16ch;
}

h2 {
  font-size: clamp(1.55rem, 3vw, 2.35rem);
  margin-bottom: 0.75rem;
}

h3 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
}

.hero-lead,
.page-lead,
.result-copy,
.topic-card p,
.benefit-card p,
.step-card p,
.info-card p,
.sample-question p,
.stat-card p,
.empty-state p,
.faq-item p,
.footer-note,
.error-item p,
.topic-progress-meta {
  color: var(--text-soft);
}

.hero-lead,
.page-lead {
  max-width: 62ch;
  font-size: clamp(1.05rem, 1.5vw, 1.22rem);
}

.hero-actions,
.inline-actions,
.card-actions,
.result-actions,
.quiz-footer {
  display: flex;
  gap: 0.95rem;
  flex-wrap: wrap;
}

.result-actions {
  margin-top: 1.35rem;
  align-items: stretch;
}

.result-actions .button {
  min-width: 8.75rem;
}

.hero-actions {
  margin-top: 1.6rem;
}

.hero-actions.centered,
.inline-actions.centered,
.result-actions.centered {
  justify-content: center;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 3.2rem;
  padding: 0.85rem 1.22rem;
  border-radius: 16px;
  border: 1px solid transparent;
  background: var(--primary);
  color: var(--primary-contrast);
  font-weight: 700;
  letter-spacing: -0.01em;
  transition: transform var(--transition), background-color var(--transition), border-color var(--transition), color var(--transition);
}

.button:hover,
.button:focus-visible {
  transform: translateY(-1px);
  background: var(--primary-strong);
}

.button-secondary {
  background: var(--surface-strong);
  color: var(--text);
  border-color: var(--border);
}

.button-secondary:hover,
.button-secondary:focus-visible {
  background: var(--surface-soft);
  border-color: var(--border-strong);
}

.button-ghost {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

.button-ghost:hover,
.button-ghost:focus-visible {
  background: var(--surface-subtle);
}

.button-small {
  min-height: 2.75rem;
  padding: 0.7rem 1rem;
  font-size: 0.95rem;
}

.text-link {
  color: var(--primary);
  font-weight: 700;
}

.text-link:hover,
.text-link:focus-visible {
  color: var(--primary-strong);
  text-decoration: underline;
  text-underline-offset: 0.18em;
}

.hero-points,
.feature-list,
.study-list,
.sample-options {
  color: var(--text-soft);
  padding-left: 1.15rem;
}

.hero-points {
  list-style: none;
  padding-left: 0;
  margin: 1.4rem 0 0;
  display: flex;
  gap: 0.7rem 1.15rem;
  flex-wrap: wrap;
}

.hero-points li {
  position: relative;
  padding-left: 0.95rem;
  color: var(--text-faint);
  font-weight: 650;
}

.hero-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.65rem;
  width: 0.42rem;
  height: 0.42rem;
  border-radius: 50%;
  background: var(--primary);
}

.feature-list,
.study-list,
.sample-options {
  display: grid;
  gap: 0.52rem;
}

.feature-list li::marker,
.study-list li::marker,
.sample-options li::marker {
  color: var(--primary);
}

.section {
  padding: 2.7rem 0;
}

.section-tight {
  padding-top: 1rem;
}

.section-muted {
  background: var(--surface-section);
  border-top: 1px solid var(--border-muted);
  border-bottom: 1px solid var(--border-muted);
}

.section-heading {
  margin-bottom: 1.5rem;
}

.section-heading.center {
  text-align: center;
}

.section-heading p:last-child,
.prose p,
.info-card p:last-child,
.benefit-card p:last-child,
.step-card p:last-child,
.sample-question p:last-child,
.topic-card p:last-child,
.empty-state p:last-child,
.footer-note,
.faq-item p:last-child {
  margin-bottom: 0;
}

.benefit-grid,
.steps-grid,
.sample-grid,
.stats-grid,
.topic-grid,
.error-list,
.topic-progress-list,
.faq-list {
  display: grid;
  gap: 1rem;
}

.benefit-grid,
.steps-grid,
.sample-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.topic-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.stats-grid {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.benefit-card,
.step-card,
.info-card,
.sample-question,
.stat-card,
.topic-card,
.panel-shell,
.quiz-card,
.empty-state,
.cta-panel {
  padding: 1.45rem;
}

.benefit-card,
.step-card,
.topic-card,
.stat-card,
.info-card,
.quiz-card,
.sample-question,
.cta-panel {
  backdrop-filter: blur(10px);
}

.step-index {
  width: 2.3rem;
  height: 2.3rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--primary-soft);
  color: var(--primary);
  font-weight: 800;
  margin-bottom: 0.9rem;
}

.topic-card {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.topic-card h3 a:hover,
.topic-card h3 a:focus-visible {
  color: var(--primary);
}

.card-actions {
  margin-top: auto;
  align-items: center;
  justify-content: space-between;
}

.cta-panel {
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 1rem;
  background: var(--surface-tint);
}

.faq-item {
  overflow: hidden;
}

.faq-item summary {
  list-style: none;
  cursor: pointer;
  position: relative;
  padding: 1.05rem 1.2rem;
  font-weight: 700;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 1.15rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-faint);
  font-size: 1.15rem;
}

.faq-item[open] summary::after {
  content: "–";
}

.faq-item p {
  padding: 0 1.2rem 1.1rem;
}

.breadcrumb {
  padding-top: 1.15rem;
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  list-style: none;
  padding: 0;
  margin: 0;
  color: var(--text-faint);
  font-size: 0.93rem;
}

.breadcrumb li + li::before {
  content: "/";
  margin-right: 0.55rem;
  color: var(--muted-faint);
}

.metric-stack {
  display: grid;
  gap: 0.95rem;
}

.metric-value {
  display: block;
  font-size: 1.9rem;
  line-height: 1;
  font-weight: 800;
  letter-spacing: -0.04em;
}

.metric-label {
  display: block;
  margin-top: 0.22rem;
  color: var(--text-faint);
}

.related-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 0.9rem;
  margin-bottom: 1rem;
}

.pill-link,
.quiz-chip,
.error-meta span {
  display: inline-flex;
  align-items: center;
  min-height: 2.2rem;
  padding: 0.38rem 0.72rem;
  border-radius: 999px;
  background: var(--surface-subtle);
  border: 1px solid var(--border);
  color: var(--text-soft);
  font-size: 0.93rem;
  font-weight: 650;
}

.pill-link:hover,
.pill-link:focus-visible {
  color: var(--text);
  background: var(--surface-tint-strong);
}

.sample-options li.correct {
  color: var(--success);
  font-weight: 700;
}

.panel-shell {
  padding: 1.25rem;
}

.panel-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.panel-title,
.subsection-title {
  margin-bottom: 0;
  font-size: 1.25rem;
}

.error-item {
  display: grid;
  gap: 0.85rem;
  padding: 1.05rem;
}

.error-meta {
  display: flex;
  gap: 0.55rem;
  flex-wrap: wrap;
}

.empty-state {
  text-align: center;
}

.empty-state.compact {
  padding: 1rem 0;
  background: transparent;
  border: 0;
  box-shadow: none;
}

.stat-card {
  display: grid;
  gap: 0.3rem;
}

.stat-card strong,
.result-tile strong {
  display: block;
  font-size: clamp(1.8rem, 2vw, 2.45rem);
  line-height: 1;
  letter-spacing: -0.04em;
}

.topic-progress-item {
  display: grid;
  gap: 0.6rem;
  padding: 0.95rem 1rem;
}

.topic-progress-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

.topic-progress-bar,
.quiz-progress {
  height: 0.7rem;
  border-radius: 999px;
  background: var(--surface-subtle);
  overflow: hidden;
}

.topic-progress-fill,
.quiz-progress-bar {
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--primary), var(--progress-end));
}

.quiz-shell {
  min-height: 18rem;
}

.quiz-shell.is-hidden {
  display: none;
}

.quiz-loading {
  padding: 2rem;
  text-align: center;
  color: var(--text-faint);
}

.quiz-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.quiz-kicker {
  color: var(--text-faint);
  font-weight: 650;
  font-size: 0.95rem;
}

.quiz-progress {
  width: 100%;
  margin-bottom: 1.1rem;
}

.quiz-question {
  font-size: clamp(1.3rem, 2.2vw, 1.7rem);
  margin-bottom: 1rem;
}

.quiz-options {
  display: grid;
  gap: 0.78rem;
}

.quiz-option {
  width: 100%;
  min-height: 3.85rem;
  padding: 1rem 1.05rem;
  text-align: left;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--surface-strong);
  color: var(--text);
  font-size: 1.04rem;
  font-weight: 650;
  transition: border-color var(--transition), background-color var(--transition), transform var(--transition);
}

.quiz-option:hover,
.quiz-option:focus-visible {
  transform: translateY(-1px);
  background: var(--surface-subtle);
  border-color: var(--option-hover-border);
}

.quiz-option.correct {
  border-color: var(--success-border);
  background: var(--success-soft);
  color: var(--text);
}

.quiz-option.incorrect {
  border-color: var(--danger-border);
  background: var(--danger-soft);
  color: var(--text);
}

.quiz-option.dimmed {
  opacity: 0.72;
}

.quiz-feedback {
  margin-top: 1rem;
  padding: 1rem 1.05rem;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--surface-strong);
}

.quiz-feedback.is-correct {
  border-color: var(--success-border);
  background: var(--success-soft);
}

.quiz-feedback.is-incorrect {
  border-color: var(--danger-border);
  background: var(--danger-soft);
}

.quiz-feedback p {
  margin-bottom: 0.4rem;
}

.quiz-feedback p:last-child {
  margin-bottom: 0;
}

.quiz-feedback.is-correct strong {
  color: var(--success);
}

.quiz-feedback.is-incorrect strong {
  color: var(--danger);
}

.quiz-running-score {
  margin: 1rem 0 0;
  color: var(--text-faint);
  font-size: 0.94rem;
  font-weight: 650;
}

.quiz-footer-next {
  justify-content: flex-end;
}

.quiz-footer-next .button {
  min-width: 10rem;
}

.quiz-footer {
  margin-top: 1rem;
  align-items: center;
  justify-content: space-between;
}

.quiz-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.timer-box {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  margin-top: 0.75rem;
}

.timer-box label {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  color: var(--text-soft);
  font-weight: 650;
}

.timer-box input {
  accent-color: var(--primary);
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  margin: 1.2rem 0;
}

.result-tile {
  padding: 1rem;
}

.prose p + p {
  margin-top: 1rem;
}

.site-footer {
  border-top: 1px solid var(--border-muted);
  background: var(--surface-section);
}

.footer-grid {
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: start;
  padding: 2rem 0 1rem;
}

.footer-brand {
  display: inline-block;
  margin-bottom: 0.55rem;
  font-size: 1.02rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(2, auto);
  gap: 0.6rem 1.35rem;
  color: var(--text-soft);
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--text);
}

.footer-bottom {
  padding: 0 0 2rem;
  color: var(--text-faint);
  font-size: 0.94rem;
}

@media (max-width: 1080px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .hero-copy {
    max-width: 100%;
  }

  .site-nav {
    gap: 0.08rem;
  }
}

@media (max-width: 960px) {
  .topic-hero-grid,
  .grid-2,
  .progress-layout,
  .cta-panel,
  .footer-grid,
  .benefit-grid,
  .sample-grid,
  .steps-grid,
  .topic-grid,
  .stats-grid,
  .result-grid {
    grid-template-columns: 1fr;
  }

  .site-nav {
    position: fixed;
    top: calc(var(--header-h) + 0.6rem);
    left: 1rem;
    right: 1rem;
    display: none;
    flex-direction: column;
    align-items: stretch;
    padding: 0.85rem;
    background: var(--surface-tint-strong);
    border: 1px solid var(--border);
    border-radius: 20px;
    box-shadow: var(--shadow-lg);
    max-height: calc(100dvh - var(--header-h) - 1.5rem);
    overflow: auto;
  }

  .nav-open .site-nav {
    display: flex;
  }

  .nav-link {
    padding: 0.95rem 1rem;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .header-shell {
    gap: 0.75rem;
  }

  .header-actions {
    margin-left: auto;
  }
}

@media (max-width: 720px) {
  :root {
    --header-h: 70px;
  }

  body {
    font-size: 15.5px;
  }

  h1 {
    max-width: 14ch;
  }

  .hero,
  .page-hero {
    padding-top: 3.25rem;
  }

  .hero-home {
    padding-top: 3.6rem;
  }

  .button,
  .quiz-option {
    width: 100%;
  }

  .hero-actions,
  .card-actions,
  .quiz-footer,
  .panel-header,
  .inline-actions,
  .result-actions,
  .topic-progress-head {
    flex-direction: column;
    align-items: stretch;
  }

  .card-actions,
  .result-actions {
    gap: 0.9rem;
  }

  .site-header {
    backdrop-filter: blur(14px);
  }

  .theme-toggle {
    min-width: 2.9rem;
    justify-content: center;
    padding: 0;
  }

  .theme-toggle-text {
    display: none;
  }

  .footer-links {
    grid-template-columns: 1fr;
  }

  .hero-panel-card,
  .panel-shell,
  .info-card,
  .topic-card,
  .sample-question,
  .step-card,
  .benefit-card,
  .stat-card,
  .quiz-card,
  .empty-state,
  .cta-panel {
    padding: 1.2rem;
  }

  .quiz-topbar,
  .quiz-meta {
    align-items: flex-start;
  }

  .hero-points {
    gap: 0.6rem 0.95rem;
  }
}

@media (max-width: 520px) {
  .container,
  .container.narrow,
  .narrow {
    width: min(100% - 1.2rem, var(--container));
  }

  h1 {
    font-size: clamp(2.1rem, 10vw, 2.9rem);
  }

  h2 {
    font-size: clamp(1.45rem, 7vw, 1.95rem);
  }

  .brand-mark {
    width: 2.45rem;
    height: 2.45rem;
  }

  .brand-text span {
    display: none;
  }

  .hero-panel-card {
    padding: 1.15rem;
  }

  .faq-item summary,
  .faq-item p {
    padding-left: 1rem;
    padding-right: 1rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}

/* v4 refinements */
:root {
  --bg: #f5f7fb;
  --bg-soft: #eef3f9;
  --surface: rgba(255, 255, 255, 0.94);
  --surface-strong: #ffffff;
  --surface-soft: #eef4fb;
  --surface-muted: rgba(255, 255, 255, 0.7);
  --border: rgba(22, 34, 54, 0.1);
  --border-strong: rgba(22, 34, 54, 0.16);
  --text: #0f172a;
  --text-soft: #334155;
  --text-faint: #526277;
  --primary: #245d9b;
  --primary-strong: #184a80;
  --primary-contrast: #ffffff;
  --primary-soft: rgba(36, 93, 155, 0.11);
  --success: #0f766e;
  --success-soft: rgba(15, 118, 110, 0.1);
  --danger: #c2413a;
  --danger-soft: rgba(194, 65, 58, 0.1);
  --bg-gradient: rgba(255, 255, 255, 0.78);
  --primary-glow: rgba(36, 93, 155, 0.08);
  --focus-ring: rgba(36, 93, 155, 0.26);
  --header-bg: rgba(245, 247, 251, 0.86);
  --border-muted: rgba(22, 34, 54, 0.08);
  --surface-tint: rgba(255, 255, 255, 0.96);
  --surface-tint-strong: rgba(255, 255, 255, 0.985);
  --surface-subtle: rgba(236, 243, 251, 0.9);
  --surface-section: linear-gradient(180deg, rgba(237, 243, 250, 0.72), rgba(248, 250, 253, 0.92));
  --primary-border-soft: rgba(36, 93, 155, 0.22);
  --muted-faint: rgba(82, 98, 119, 0.78);
  --progress-end: #6b8fb6;
  --option-hover-border: rgba(36, 93, 155, 0.3);
  --success-border: rgba(15, 118, 110, 0.28);
  --danger-border: rgba(194, 65, 58, 0.28);
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.03), 0 10px 24px rgba(15, 23, 42, 0.04);
  --shadow-md: 0 16px 36px rgba(15, 23, 42, 0.05);
  --shadow-lg: 0 20px 48px rgba(15, 23, 42, 0.08);
}

html[data-theme="dark"] {
  --bg: #0b1220;
  --bg-soft: #101827;
  --surface: rgba(17, 24, 39, 0.94);
  --surface-strong: #121b2c;
  --surface-soft: #1a2638;
  --surface-muted: rgba(17, 24, 39, 0.74);
  --border: rgba(148, 163, 184, 0.2);
  --border-strong: rgba(148, 163, 184, 0.28);
  --text: #eff4fb;
  --text-soft: #cfd8e5;
  --text-faint: #9fb0c5;
  --primary: #8cb8eb;
  --primary-strong: #a5c8f2;
  --primary-contrast: #08111c;
  --primary-soft: rgba(140, 184, 235, 0.16);
  --success: #8ee0d3;
  --success-soft: rgba(94, 234, 212, 0.12);
  --danger: #f2b1aa;
  --danger-soft: rgba(242, 177, 170, 0.12);
  --bg-gradient: rgba(10, 16, 29, 0.84);
  --primary-glow: rgba(140, 184, 235, 0.12);
  --focus-ring: rgba(140, 184, 235, 0.34);
  --header-bg: rgba(11, 18, 32, 0.86);
  --border-muted: rgba(148, 163, 184, 0.16);
  --surface-tint: rgba(19, 28, 43, 0.95);
  --surface-tint-strong: rgba(19, 28, 43, 0.985);
  --surface-subtle: rgba(24, 37, 56, 0.95);
  --surface-section: linear-gradient(180deg, rgba(15, 23, 35, 0.78), rgba(11, 18, 32, 0.92));
  --primary-border-soft: rgba(140, 184, 235, 0.26);
  --muted-faint: rgba(159, 176, 197, 0.78);
  --progress-end: #d0e2f7;
  --option-hover-border: rgba(140, 184, 235, 0.42);
  --success-border: rgba(142, 224, 211, 0.4);
  --danger-border: rgba(242, 177, 170, 0.34);
  --shadow-sm: none;
  --shadow-md: none;
  --shadow-lg: none;
}

body {
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 17px;
  line-height: 1.7;
}

.brand-text strong,
.nav-link,
.button,
.quiz-option,
.faq-item summary {
  letter-spacing: -0.02em;
}

.brand-text strong {
  font-size: 1.02rem;
}

.brand-text span,
.footer-note,
.topic-progress-meta,
.quiz-running-score,
.quiz-kicker,
.mini-label,
.metric-label {
  color: var(--text-faint);
}

.site-header {
  box-shadow: 0 1px 0 rgba(15, 23, 42, 0.03);
}

.hero,
.page-hero {
  padding: 4.8rem 0 2.4rem;
}

.hero-home {
  padding-top: 5.2rem;
}

.hero-lead,
.page-lead {
  color: var(--text-soft);
  font-size: clamp(1.12rem, 1.6vw, 1.28rem);
}

h1 {
  max-width: 13ch;
}

h2 {
  line-height: 1.12;
}

.button {
  min-height: 3.3rem;
  padding: 0.92rem 1.28rem;
  box-shadow: 0 8px 20px rgba(36, 93, 155, 0.14);
}

.button-secondary,
.button-ghost {
  box-shadow: none;
}

.button-secondary {
  background: var(--surface-strong);
  border-color: rgba(36, 93, 155, 0.14);
}

.button-ghost {
  background: var(--surface-soft);
  border-color: transparent;
}

html[data-theme="dark"] .button-secondary {
  background: rgba(21, 32, 48, 0.98);
  color: var(--text);
  border-color: rgba(140, 184, 235, 0.18);
}

html[data-theme="dark"] .button-ghost {
  background: rgba(24, 37, 56, 0.95);
  color: var(--text);
  border-color: rgba(140, 184, 235, 0.12);
}

.hero-panel-card,
.panel-shell,
.info-card,
.topic-card,
.sample-question,
.step-card,
.benefit-card,
.stat-card,
.quiz-card,
.empty-state,
.cta-panel,
.faq-item,
.error-item,
.topic-progress-item,
.result-tile {
  background: var(--surface);
}

.panel-shell,
.quiz-card,
.cta-panel,
.hero-panel-card {
  border-radius: 24px;
}

.stat-card {
  gap: 0.5rem;
}

.stat-card p {
  font-size: 0.95rem;
  line-height: 1.45;
}

.stats-grid {
  gap: 0.9rem;
  margin-bottom: 1rem;
}

.progress-layout {
  grid-template-columns: minmax(300px, 0.7fr) minmax(0, 1.3fr);
  align-items: start;
}

.progress-summary-grid {
  display: grid;
  gap: 1rem;
}

.summary-panel {
  padding: 1.15rem;
  border-radius: 20px;
  background: var(--surface-soft);
  border: 1px solid var(--border);
}

.summary-panel-accent {
  background: linear-gradient(180deg, var(--surface-strong), var(--surface-soft));
}

.summary-panel h3 {
  font-size: 1.18rem;
  margin-bottom: 0.45rem;
}

.summary-panel p {
  color: var(--text-soft);
}

.summary-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.8rem;
}

.summary-metric,
.summary-list div {
  display: grid;
  gap: 0.22rem;
  padding: 0.9rem 0.95rem;
  border-radius: 16px;
  background: var(--surface-strong);
  border: 1px solid var(--border);
}

.summary-metric span,
.summary-list span {
  color: var(--text-faint);
  font-size: 0.9rem;
}

.summary-metric strong,
.summary-list strong {
  font-size: 1.18rem;
  line-height: 1.1;
  letter-spacing: -0.03em;
}

.summary-list {
  display: grid;
  gap: 0.75rem;
  margin: 1rem 0;
}

.topic-progress-list {
  gap: 0.85rem;
}

.topic-progress-item {
  gap: 0.72rem;
  padding: 1rem 1.05rem;
}

.topic-progress-head strong {
  font-size: 1rem;
}

.topic-progress-meta {
  font-size: 0.94rem;
}

.topic-progress-bar,
.quiz-progress {
  height: 0.62rem;
  background: rgba(36, 93, 155, 0.08);
}

html[data-theme="dark"] .topic-progress-bar,
html[data-theme="dark"] .quiz-progress {
  background: rgba(140, 184, 235, 0.12);
}

.quiz-topbar {
  align-items: center;
  margin-bottom: 1.15rem;
}

.quiz-meta {
  align-items: center;
}

.quiz-chip,
.error-meta span {
  min-height: 2.35rem;
  padding: 0.45rem 0.82rem;
  color: var(--text-soft);
  background: var(--surface-soft);
}

.quiz-chip-timer {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  padding-inline: 0.95rem;
  white-space: nowrap;
}

.quiz-chip-label {
  color: var(--text-faint);
  font-weight: 700;
}

.quiz-chip-timer strong {
  font-size: 1rem;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--text);
}

.quiz-question {
  font-size: clamp(1.45rem, 2.2vw, 1.82rem);
  line-height: 1.18;
}

.quiz-option {
  min-height: 4rem;
  padding: 1.02rem 1.08rem;
  font-size: 1.08rem;
  border-color: rgba(22, 34, 54, 0.12);
}

html[data-theme="dark"] .quiz-option {
  background: rgba(18, 27, 44, 0.98);
  border-color: rgba(148, 163, 184, 0.18);
}

.quiz-feedback {
  margin-top: 1.1rem;
}

.timer-box {
  margin-top: 1rem;
}

.timer-box label {
  padding: 0.85rem 1rem;
  border-radius: 16px;
  background: var(--surface-soft);
  border: 1px solid var(--border);
}

.site-footer {
  background: transparent;
}

.footer-grid {
  padding: 1.65rem 0 0.8rem;
  gap: 0.9rem 1.4rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.7rem 1rem;
  font-size: 0.95rem;
}

.footer-bottom {
  padding: 0 0 1.5rem;
}

@media (max-width: 960px) {
  .progress-layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  body {
    font-size: 16px;
  }

  .hero,
  .page-hero {
    padding-top: 3.3rem;
  }

  .stats-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .summary-metrics {
    grid-template-columns: 1fr 1fr;
  }

  .quiz-meta {
    width: 100%;
    gap: 0.5rem;
  }

  .quiz-chip,
  .quiz-chip-timer {
    min-height: 2.6rem;
  }

  .footer-grid {
    padding-top: 1.4rem;
  }

  .footer-links {
    justify-content: flex-start;
    gap: 0.55rem 0.9rem;
    font-size: 0.92rem;
  }

  .footer-note {
    max-width: 34ch;
  }
}

@media (max-width: 520px) {
  h1 {
    font-size: clamp(2.15rem, 9.5vw, 2.95rem);
  }

  .stats-grid,
  .summary-metrics {
    grid-template-columns: 1fr;
  }

  .stat-card strong,
  .result-tile strong {
    font-size: 1.95rem;
  }

  .quiz-topbar {
    align-items: stretch;
  }

  .quiz-chip,
  .quiz-chip-timer {
    width: fit-content;
    max-width: 100%;
  }

  .quiz-chip-timer {
    padding-right: 0.85rem;
  }

  .site-footer {
    margin-top: 1rem;
  }

  .footer-brand {
    margin-bottom: 0.35rem;
  }

  .footer-note {
    font-size: 0.92rem;
  }

  .footer-links {
    gap: 0.45rem 0.8rem;
    font-size: 0.9rem;
  }

  .footer-bottom {
    font-size: 0.88rem;
    padding-bottom: 1.2rem;
  }
}

/* v5 product and study refinements */
.home-focus-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 1rem;
}

.home-focus-card {
  display: grid;
  gap: 0.7rem;
  padding: 1.35rem;
  border: 1px solid var(--border);
  border-radius: 22px;
  background: var(--surface);
  box-shadow: var(--shadow-sm);
}

.home-focus-highlight {
  background: linear-gradient(180deg, var(--surface-strong), var(--surface-soft));
}

.home-focus-card h3,
.progress-overview-card h3,
.result-next-step h3 {
  margin: 0;
  font-size: clamp(1.3rem, 2vw, 1.7rem);
  line-height: 1.12;
}

.home-focus-card p,
.progress-overview-card p,
.result-next-step p,
.topic-progress-sub,
.quiz-support,
.quiz-running-note,
.summary-empty,
.session-item p {
  margin: 0;
  color: var(--text-soft);
}

.home-focus-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
}

.mode-switch {
  display: inline-grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.6rem;
  padding: 0.45rem;
  margin: 1rem 0 0.45rem;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--surface-soft);
}

.mode-pill {
  position: relative;
  display: block;
}

.mode-pill input {
  position: absolute;
  inset: 0;
  opacity: 0;
}

.mode-pill span {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 2.9rem;
  padding: 0.75rem 1rem;
  border-radius: 16px;
  font-weight: 700;
  color: var(--text-soft);
  transition: background var(--transition), color var(--transition), box-shadow var(--transition);
}

.mode-pill input:checked + span {
  background: var(--surface-strong);
  color: var(--text);
  box-shadow: var(--shadow-sm);
}

.mode-pill input:focus-visible + span {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
}

.quiz-support,
.quiz-running-note,
.quiz-feedback-note {
  font-size: 0.98rem;
}

.quiz-meta-wrap {
  flex-wrap: wrap;
  justify-content: flex-end;
}

.quiz-chip-timer {
  min-height: 2.9rem;
  padding-inline: 1rem;
  border-radius: 18px;
}

.quiz-chip-timer .timer-value {
  font-variant-numeric: tabular-nums;
  font-weight: 800;
  font-size: 1.08rem;
  letter-spacing: -0.03em;
  color: var(--text);
}

.quiz-feedback-note {
  margin-top: 0.35rem;
}

.result-next-step {
  display: grid;
  gap: 0.5rem;
  margin-top: 1.15rem;
  padding: 1rem 1.05rem;
  border-radius: 18px;
  background: var(--surface-soft);
  border: 1px solid var(--border);
}

.error-summary-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.9rem;
  margin-bottom: 1rem;
}

.error-summary-card {
  display: grid;
  gap: 0.22rem;
  padding: 1rem;
  border-radius: 18px;
  background: var(--surface-soft);
  border: 1px solid var(--border);
}

.error-summary-card strong {
  font-size: 1.6rem;
  line-height: 1;
  letter-spacing: -0.04em;
}

.error-summary-card span {
  color: var(--text-soft);
}

.error-stack {
  display: grid;
  gap: 0.95rem;
}

.error-item-head {
  margin-bottom: 0.55rem;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2rem;
  padding: 0.28rem 0.72rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-soft);
  color: var(--text-soft);
  font-size: 0.82rem;
  font-weight: 700;
}

.status-pill-good {
  color: var(--success);
  background: var(--success-soft);
  border-color: var(--success-border);
}

.status-pill-progress {
  color: var(--primary);
  background: var(--primary-soft);
  border-color: var(--primary-border-soft);
}

.status-pill-alert {
  color: var(--danger);
  background: var(--danger-soft);
  border-color: var(--danger-border);
}

.progress-overview-card {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(280px, 0.8fr);
  gap: 1rem;
  padding: 1.2rem;
  margin-bottom: 1rem;
  border-radius: 24px;
  border: 1px solid var(--border);
  background: linear-gradient(180deg, var(--surface-strong), var(--surface-soft));
}

.progress-overview-metrics {
  display: grid;
  gap: 0.75rem;
}

.progress-overview-metrics div {
  display: grid;
  gap: 0.22rem;
  padding: 0.9rem 0.95rem;
  border-radius: 16px;
  background: var(--surface-strong);
  border: 1px solid var(--border);
}

.progress-overview-metrics span,
.metric-row span,
.session-item span {
  color: var(--text-faint);
}

.progress-overview-metrics strong {
  font-size: 1.05rem;
  line-height: 1.2;
}

.summary-panel-wide {
  grid-column: 1 / -1;
}

.session-list {
  display: grid;
  gap: 0.75rem;
}

.session-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.85rem;
  padding: 0.9rem 0.95rem;
  border-radius: 16px;
  background: var(--surface-strong);
  border: 1px solid var(--border);
}

.topic-progress-sub {
  margin-top: 0.18rem;
  font-size: 0.95rem;
}

.metric-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  font-size: 0.94rem;
}

.metric-row strong {
  color: var(--text);
  font-size: 0.98rem;
}

.topic-progress-fill-accuracy {
  background: linear-gradient(90deg, var(--success), var(--progress-end));
}

.site-footer {
  border-top: 1px solid var(--border-muted);
}

.footer-note {
  max-width: 34ch;
}

@media (max-width: 1080px) {
  .home-focus-grid {
    grid-template-columns: 1fr 1fr;
  }

  .home-focus-highlight {
    grid-column: 1 / -1;
  }
}

@media (max-width: 900px) {
  .progress-overview-card {
    grid-template-columns: 1fr;
  }

  .error-summary-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .home-focus-grid,
  .progress-summary-grid {
    grid-template-columns: 1fr;
  }

  .mode-switch {
    width: 100%;
  }

  .quiz-meta-wrap {
    justify-content: flex-start;
  }

  .session-item {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 560px) {
  .home-focus-card,
  .progress-overview-card,
  .summary-panel,
  .error-summary-card,
  .result-next-step {
    padding: 1rem;
    border-radius: 20px;
  }

  .quiz-chip-timer {
    width: 100%;
    justify-content: space-between;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 0.8rem;
  }

  .footer-links {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    justify-content: flex-start;
    gap: 0.4rem 0.9rem;
    font-size: 0.89rem;
  }

  .footer-bottom {
    padding-top: 0.1rem;
  }
}
.progress-summary-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}


/* v6 refinements */
.button:disabled,
.button[disabled],
.quiz-option:disabled {
  cursor: not-allowed;
}

.button:disabled,
.button[disabled] {
  background: var(--surface-soft);
  border-color: var(--border);
  color: var(--text-faint);
  box-shadow: none;
  transform: none;
}

html[data-theme="dark"] .button-secondary {
  background: #162334;
  color: #eef4fb;
  border-color: rgba(156, 190, 226, 0.28);
}

html[data-theme="dark"] .button-secondary:hover,
html[data-theme="dark"] .button-secondary:focus-visible {
  background: #1c2b40;
  border-color: rgba(178, 207, 238, 0.4);
}

html[data-theme="dark"] .button-ghost {
  background: rgba(24, 36, 54, 0.78);
  color: #eef4fb;
  border-color: rgba(156, 190, 226, 0.2);
}

html[data-theme="dark"] .button-ghost:hover,
html[data-theme="dark"] .button-ghost:focus-visible {
  background: rgba(31, 46, 67, 0.92);
  border-color: rgba(178, 207, 238, 0.34);
}

.progress-overview-card {
  grid-template-columns: 1fr;
  gap: 1rem;
}

.progress-overview-main {
  display: grid;
  gap: 0.45rem;
}

.progress-overview-metrics-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.progress-summary-stack {
  display: grid;
  gap: 1rem;
}

.summary-panel-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.summary-list-compact {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.summary-list-compact div {
  min-height: 5.5rem;
  align-content: start;
}

.summary-empty {
  padding: 0.25rem 0 0;
}

.session-item {
  gap: 0.8rem;
  justify-content: space-between;
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--border);
}

.session-item:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.summary-panel .inline-actions {
  margin-top: 1rem;
}

.quiz-feedback {
  display: grid;
  gap: 0.8rem;
}

.quiz-explanation {
  border: 1px solid var(--border);
  border-radius: 18px;
  background: var(--surface-soft);
  overflow: clip;
}

.quiz-explanation summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.95rem 1rem;
  font-weight: 700;
  color: var(--text);
}

.quiz-explanation summary::-webkit-details-marker {
  display: none;
}

.quiz-explanation summary::after {
  content: "+";
  font-size: 1.15rem;
  line-height: 1;
  color: var(--text-soft);
}

.quiz-explanation[open] summary::after {
  content: "−";
}

.quiz-explanation-body {
  padding: 0 1rem 1rem;
  color: var(--text-soft);
}

.quiz-feedback-note {
  margin-top: 0.4rem;
}

@media (max-width: 900px) {
  .progress-layout {
    grid-template-columns: 1fr;
  }

  .progress-overview-metrics-3,
  .summary-panel-grid,
  .summary-list-compact {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .progress-overview-metrics-3 {
    gap: 0.75rem;
  }

  .summary-panel-grid {
    gap: 0.75rem;
  }
}


/* v7 simplification */
.quiz-feedback-card {
  padding: 1rem 1.05rem;
  border-radius: 20px;
  border: 1px solid var(--border);
}

.quiz-feedback-title,
.quiz-answer-note {
  margin: 0;
}

.quiz-answer-note {
  color: var(--text-soft);
}

.quiz-explanation-inline {
  padding: 0.95rem 1rem;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--surface-soft);
}

.quiz-explanation-inline p {
  margin: 0;
  color: var(--text-soft);
}

.quiz-feedback-card.is-correct {
  background: var(--success-soft);
  border-color: var(--success-border);
}

.quiz-feedback-card.is-incorrect {
  background: var(--danger-soft);
  border-color: var(--danger-border);
}

.quiz-feedback-card.is-correct .quiz-explanation-inline,
.quiz-feedback-card.is-incorrect .quiz-explanation-inline {
  background: var(--surface-soft);
}

.progress-overview-card-simple {
  gap: 1rem;
}

.summary-stat-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.8rem;
}

.summary-stat-card {
  display: grid;
  gap: 0.28rem;
  padding: 0.95rem 1rem;
  border-radius: 18px;
  background: var(--surface-strong);
  border: 1px solid var(--border);
}

.summary-stat-card span {
  color: var(--text-faint);
  font-size: 0.92rem;
}

.summary-stat-card strong {
  font-size: 1.15rem;
  line-height: 1.2;
  color: var(--text);
  word-break: break-word;
}

.progress-summary-stack-clean {
  grid-template-columns: 1fr;
}

.summary-actions-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1rem;
}

.summary-panel .summary-list-compact {
  margin-top: 1rem;
}

.session-list-clean {
  gap: 0.5rem;
}

.session-item-clean {
  padding: 0.9rem 1rem;
  border-radius: 16px;
  background: var(--surface-strong);
  border: 1px solid var(--border);
}

.session-item-clean p {
  margin: 0.2rem 0 0;
}

@media (max-width: 900px) {
  .summary-stat-grid,
  .summary-list-compact,
  .summary-panel-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .quiz-feedback-card,
  .quiz-explanation-inline,
  .summary-stat-card,
  .session-item-clean {
    border-radius: 16px;
  }
}


/* v8 cleanup */
.summary-stat-grid {
  display: none;
}

@media (max-width: 720px) {
  .related-links {
    margin-top: 1rem;
  }
}