/* ==========================================================================
   HCI Exam Trainer. Apple/macOS inspired styles.
   ========================================================================== */

/* --- Design tokens --------------------------------------------------------- */
:root {
  /* Color */
  --bg: #fbfbfd;
  --bg-elevated: #ffffff;
  --bg-translucent: rgba(255, 255, 255, 0.72);
  --bg-subtle: #f5f5f7;
  --border: rgba(0, 0, 0, 0.08);
  --border-strong: rgba(0, 0, 0, 0.14);
  --text: #1d1d1f;
  --text-secondary: #6e6e73;
  --text-tertiary: #86868b;
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --accent-pressed: #006edb;
  --accent-soft: rgba(0, 113, 227, 0.1);
  --success: #34c759;
  --success-soft: rgba(52, 199, 89, 0.12);
  --danger: #ff3b30;
  --danger-soft: rgba(255, 59, 48, 0.12);
  --warning: #ff9500;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.08), 0 2px 6px rgba(0, 0, 0, 0.04);
  --shadow-xl: 0 24px 60px rgba(0, 0, 0, 0.12), 0 4px 12px rgba(0, 0, 0, 0.06);

  /* Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;
  --radius-full: 999px;

  /* Spacing scale (4px) */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;
  --space-16: 64px;
  --space-20: 80px;

  /* Type */
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "Segoe UI", system-ui, sans-serif;
  --font-mono: "SF Mono", ui-monospace, "Menlo", "Monaco", monospace;

  /* Motion */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --duration-fast: 150ms;
  --duration: 240ms;
  --duration-slow: 400ms;
}

/* Dark theme: applied either by explicit data-theme="dark" (user choice)
   or by the system preference when no explicit choice is set. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #000000;
    --bg-elevated: #1c1c1e;
    --bg-translucent: rgba(28, 28, 30, 0.72);
    --bg-subtle: #2c2c2e;
    --border: rgba(255, 255, 255, 0.1);
    --border-strong: rgba(255, 255, 255, 0.18);
    --text: #f5f5f7;
    --text-secondary: #a1a1a6;
    --text-tertiary: #6e6e73;
    --accent: #0a84ff;
    --accent-hover: #2391ff;
    --accent-pressed: #0a78f0;
    --accent-soft: rgba(10, 132, 255, 0.16);
    --success: #30d158;
    --success-soft: rgba(48, 209, 88, 0.18);
    --danger: #ff453a;
    --danger-soft: rgba(255, 69, 58, 0.18);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.5);
  }
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg: #000000;
  --bg-elevated: #1c1c1e;
  --bg-translucent: rgba(28, 28, 30, 0.72);
  --bg-subtle: #2c2c2e;
  --border: rgba(255, 255, 255, 0.1);
  --border-strong: rgba(255, 255, 255, 0.18);
  --text: #f5f5f7;
  --text-secondary: #a1a1a6;
  --text-tertiary: #6e6e73;
  --accent: #0a84ff;
  --accent-hover: #2391ff;
  --accent-pressed: #0a78f0;
  --accent-soft: rgba(10, 132, 255, 0.16);
  --success: #30d158;
  --success-soft: rgba(48, 209, 88, 0.18);
  --danger: #ff453a;
  --danger-soft: rgba(255, 69, 58, 0.18);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.5);
}

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

/* --- Reset & base ---------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.5;
  color: var(--text);
  background: var(--bg);
  min-height: 100vh;
  letter-spacing: -0.01em;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  letter-spacing: -0.03em;
}

h2 {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
}

h3 {
  font-size: 1.25rem;
}

p {
  margin: 0;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: opacity var(--duration-fast) var(--ease-out);
}

a:hover {
  opacity: 0.75;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

::selection {
  background: var(--accent-soft);
}

/* --- Layout helpers -------------------------------------------------------- */
.container {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.container-narrow {
  max-width: 680px;
}

.muted {
  color: var(--text-secondary);
}

.tertiary {
  color: var(--text-tertiary);
}

/* --- Buttons --------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 11px 22px;
  border-radius: var(--radius-full);
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  transition: background-color 120ms ease-out, transform 120ms ease-out,
    box-shadow 120ms ease-out;
  user-select: none;
  white-space: nowrap;
}

/* Buttons rendered as links should not inherit the global a:hover opacity. */
a.btn:hover {
  opacity: 1;
}

.btn:active {
  transform: scale(0.97);
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover:not(:disabled) {
  background: var(--accent-hover);
}

.btn-primary:active:not(:disabled) {
  background: var(--accent-pressed);
}

.btn-secondary {
  background: var(--bg-subtle);
  color: var(--text);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--border);
}

.btn-ghost {
  background: transparent;
  color: var(--accent);
  padding: 8px 14px;
}

.btn-ghost:hover:not(:disabled) {
  background: var(--accent-soft);
}

.btn-lg {
  padding: 14px 28px;
  font-size: 1.05rem;
}

.btn-block {
  width: 100%;
}

/* --- Card ------------------------------------------------------------------ */
.card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: var(--space-8);
}

/* --- Top nav --------------------------------------------------------------- */
.topnav {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  background: var(--bg-translucent);
  border-bottom: 1px solid var(--border);
}

.topnav-inner {
  max-width: 1080px;
  margin: 0 auto;
  height: 52px;
  padding: 0 var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  text-decoration: none;
}

a.brand:hover {
  opacity: 1;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), #5e9bff);
  color: #fff;
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.05em;
  box-shadow: 0 1px 2px rgba(0, 113, 227, 0.2),
    inset 0 1px 0 rgba(255, 255, 255, 0.18);
}

.brand-name {
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: -0.01em;
}

.brand-name .muted-word {
  color: var(--text-tertiary);
  font-weight: 500;
}

/* Topnav CTA: blue pill, sized to fit the 52px nav row */
.topnav-cta {
  padding: 7px 16px;
  font-size: 0.875rem;
  font-weight: 500;
}

/* Legacy class kept as alias so existing pages still render. */
.topnav-link {
  padding: 7px 16px;
  font-size: 0.875rem;
  font-weight: 500;
  color: #fff;
  background: var(--accent);
  border-radius: var(--radius-full);
  transition: background var(--duration-fast) var(--ease-out),
    transform var(--duration-fast) var(--ease-out);
}

.topnav-link:hover {
  background: var(--accent-hover);
  opacity: 1;
}

/* --- Landing page ---------------------------------------------------------- */
.hero {
  text-align: center;
  padding: var(--space-20) var(--space-6) var(--space-12);
}

.hero-eyebrow {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  margin-bottom: var(--space-5);
  letter-spacing: 0;
}

.hero-title {
  background: linear-gradient(180deg, var(--text), var(--text-secondary));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: var(--space-4);
}

.hero-subtitle {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto var(--space-8);
  line-height: 1.5;
}

.hero-actions {
  display: flex;
  gap: var(--space-3);
  justify-content: center;
  flex-wrap: wrap;
}

/* Footer: shared between landing and exam pages */
.site-footer {
  padding: var(--space-8) var(--space-6) var(--space-10);
  text-align: center;
}

.byline-line {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  max-width: 480px;
  width: 100%;
  margin: 0 auto;
  font-size: 0.9rem;
  color: var(--text-tertiary);
  letter-spacing: 0;
}

.byline-rule {
  flex: 1;
  height: 1px;
  background: linear-gradient(
    90deg,
    transparent,
    var(--border-strong),
    transparent
  );
}

.byline-text {
  flex-shrink: 0;
  white-space: nowrap;
}

.byline-name {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-left: 6px;
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
  transition: opacity 120ms ease-out;
}

.byline-name:hover {
  opacity: 0.75;
}

.byline-arrow {
  opacity: 0.7;
  transition: transform 120ms ease-out;
}

.byline-name:hover .byline-arrow {
  transform: translate(1px, -1px);
}

/* Hochschule attribution row */
.school {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-top: var(--space-5);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-tertiary);
}

.school-logo {
  height: 22px;
  width: auto;
  opacity: 0.7;
  transition: opacity 120ms ease-out;
}

@media (prefers-color-scheme: dark) {
  .school-logo {
    filter: invert(1) brightness(1.1);
  }
}

.school:hover .school-logo {
  opacity: 1;
}

/* --- Exam: resume banner --------------------------------------------------- */
.resume-banner {
  padding: var(--space-6) var(--space-6) 0;
}

.resume-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
  padding: var(--space-4) var(--space-5);
  background: var(--accent-soft);
  border: 1px solid color-mix(in srgb, var(--accent) 22%, transparent);
  border-radius: var(--radius-lg);
  animation: fadeUp var(--duration) var(--ease-out);
}

.resume-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.resume-eyebrow {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  color: var(--accent);
}

.resume-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.01em;
}

.resume-meta {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-variant-numeric: tabular-nums;
}

.resume-actions {
  display: flex;
  gap: var(--space-2);
  flex-shrink: 0;
}

@media (max-width: 600px) {
  .resume-card {
    flex-direction: column;
    align-items: stretch;
    text-align: left;
  }
  .resume-actions {
    justify-content: flex-end;
  }
}

/* --- Exam: topic selector -------------------------------------------------- */
.page-header {
  padding: var(--space-12) var(--space-6) var(--space-6);
  text-align: center;
}

.page-header h1 {
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  margin-bottom: var(--space-2);
}

.page-header p {
  color: var(--text-secondary);
  font-size: 1.05rem;
}

.section {
  padding: var(--space-4) var(--space-6) var(--space-12);
}

.section-title {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  color: var(--text-tertiary);
  margin-bottom: var(--space-3);
  padding-left: var(--space-4);
}

.preset-row {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
  margin-bottom: var(--space-4);
  padding: 0 var(--space-1);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: var(--radius-full);
  background: var(--bg-elevated);
  color: var(--text);
  border: 1px solid var(--border);
  transition: all var(--duration-fast) var(--ease-out);
}

.chip:hover {
  border-color: var(--border-strong);
  background: var(--bg-subtle);
}

.chip:active {
  transform: scale(0.97);
}

.topic-list {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.topic-row {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-5);
  cursor: pointer;
  transition: background var(--duration-fast) var(--ease-out);
  border-bottom: 1px solid var(--border);
  user-select: none;
}

.topic-row:last-child {
  border-bottom: none;
}

.topic-row:hover {
  background: var(--bg-subtle);
}

.topic-row.disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

.topic-row.disabled:hover {
  background: transparent;
}

.topic-info {
  flex: 1;
  min-width: 0;
}

.topic-title {
  font-size: 0.98rem;
  font-weight: 500;
  color: var(--text);
}

.topic-meta {
  font-size: 0.82rem;
  color: var(--text-tertiary);
  margin-top: 2px;
}

.topic-badge {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  background: var(--accent-soft);
  color: var(--accent);
}

.topic-badge.empty {
  background: var(--bg-subtle);
  color: var(--text-tertiary);
}

/* iOS-style checkbox */
.checkbox {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1.5px solid var(--border-strong);
  background: var(--bg-elevated);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--duration-fast) var(--ease-out);
  position: relative;
}

.topic-row[data-checked="true"] .checkbox {
  background: var(--accent);
  border-color: var(--accent);
}

.checkbox::after {
  content: "";
  width: 6px;
  height: 10px;
  border-right: 2px solid #fff;
  border-bottom: 2px solid #fff;
  transform: rotate(45deg) translate(-1px, -1px) scale(0);
  transition: transform var(--duration-fast) var(--ease-out);
  margin-bottom: 2px;
}

.topic-row[data-checked="true"] .checkbox::after {
  transform: rotate(45deg) translate(-1px, -1px) scale(1);
}

.start-bar {
  position: sticky;
  bottom: 0;
  background: var(--bg-translucent);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-top: 1px solid var(--border);
  padding: var(--space-4) var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  z-index: 30;
}

.start-bar .summary {
  font-size: 0.92rem;
  color: var(--text-secondary);
}

.start-bar .summary strong {
  color: var(--text);
  font-weight: 600;
}

/* --- Exam: quiz screen ----------------------------------------------------- */
.quiz {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-8) var(--space-6) var(--space-20);
}

.progress {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-6);
}

.progress-track {
  flex: 1;
  height: 4px;
  background: var(--bg-subtle);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: var(--radius-full);
  transition: width var(--duration-slow) var(--ease-out);
}

.progress-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-variant-numeric: tabular-nums;
  flex-shrink: 0;
}

.q-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-md);
  animation: fadeUp var(--duration-slow) var(--ease-out);
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.q-meta {
  display: flex;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
  flex-wrap: wrap;
}

.tag {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  background: var(--bg-subtle);
  color: var(--text-secondary);
}

.tag.accent {
  background: var(--accent-soft);
  color: var(--accent);
}

.q-text {
  font-size: 1.2rem;
  font-weight: 500;
  margin-bottom: var(--space-6);
  line-height: 1.45;
}

.q-sketch {
  margin: 0 0 var(--space-6);
  padding: var(--space-4);
  background: var(--bg-subtle);
  border-radius: var(--radius-md);
  display: flex;
  justify-content: center;
}

.q-sketch svg {
  max-width: 100%;
  height: auto;
}

.q-hint {
  margin: -8px 0 var(--space-3);
  font-size: 0.82rem;
  color: var(--text-tertiary);
  font-style: italic;
}

.options {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

/* Square mark for multi-select to visually distinguish from single-select */
.options[data-multi="true"] .option-mark {
  border-radius: 6px;
}

.option {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4);
  background: var(--bg-elevated);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  cursor: pointer;
  text-align: left;
  font-size: 0.98rem;
  color: var(--text);
  transition: all var(--duration-fast) var(--ease-out);
}

.option:hover:not(:disabled) {
  border-color: var(--border-strong);
  background: var(--bg-subtle);
}

.option[data-selected="true"] {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.option[data-state="correct"] {
  border-color: var(--success);
  background: var(--success-soft);
  color: var(--text);
}

.option[data-state="wrong"] {
  border-color: var(--danger);
  background: var(--danger-soft);
  color: var(--text);
}

.option[data-state="answer"] {
  border-color: var(--success);
  border-style: dashed;
  color: var(--text);
}

.option:disabled {
  cursor: default;
}

.option-mark {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1.5px solid var(--border-strong);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  color: #fff;
  transition: all var(--duration-fast) var(--ease-out);
}

.option[data-selected="true"] .option-mark {
  background: var(--accent);
  border-color: var(--accent);
}

.option[data-state="correct"] .option-mark {
  background: var(--success);
  border-color: var(--success);
}

.option[data-state="wrong"] .option-mark {
  background: var(--danger);
  border-color: var(--danger);
}

.option[data-state="answer"] .option-mark {
  background: var(--success);
  border-color: var(--success);
}

.short-input {
  width: 100%;
  padding: 14px 16px;
  font-family: inherit;
  font-size: 1rem;
  color: var(--text);
  background: var(--bg-elevated);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  transition: border var(--duration-fast) var(--ease-out),
    box-shadow var(--duration-fast) var(--ease-out);
  resize: vertical;
  min-height: 100px;
  letter-spacing: -0.01em;
}

.short-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-soft);
}

.short-grading {
  display: flex;
  gap: var(--space-2);
  margin-top: var(--space-4);
}

.grade-btn {
  flex: 1;
  padding: 11px 16px;
  border-radius: var(--radius-md);
  font-size: 0.92rem;
  font-weight: 500;
  border: 1.5px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text);
  transition: all var(--duration-fast) var(--ease-out);
}

.grade-btn[data-style="correct"] {
  border-color: var(--success);
  color: var(--success);
}

.grade-btn[data-style="correct"]:hover:not(:disabled) {
  background: var(--success-soft);
}

.grade-btn[data-style="wrong"] {
  border-color: var(--danger);
  color: var(--danger);
}

.grade-btn[data-style="wrong"]:hover:not(:disabled) {
  background: var(--danger-soft);
}

.grade-btn[data-style="partial"] {
  border-color: var(--warning);
  color: var(--warning);
}

.grade-btn[data-style="partial"]:hover:not(:disabled) {
  background: rgba(255, 149, 0, 0.12);
}

/* Selected (clicked) state: filled with the matching color */
.grade-btn[data-selected="true"][data-style="correct"] {
  background: var(--success);
  color: #fff;
  border-color: var(--success);
  box-shadow: 0 1px 4px rgba(52, 199, 89, 0.25);
}

.grade-btn[data-selected="true"][data-style="partial"] {
  background: var(--warning);
  color: #fff;
  border-color: var(--warning);
  box-shadow: 0 1px 4px rgba(255, 149, 0, 0.25);
}

.grade-btn[data-selected="true"][data-style="wrong"] {
  background: var(--danger);
  color: #fff;
  border-color: var(--danger);
  box-shadow: 0 1px 4px rgba(255, 59, 48, 0.25);
}

/* After a grade is chosen, fade the unchosen ones so the selection stands out.
   Buttons remain clickable so the user can correct a misclick. */
.short-grading[data-graded="true"] .grade-btn:not([data-selected="true"]) {
  opacity: 0.55;
}

.feedback {
  margin-top: var(--space-5);
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius-md);
  background: var(--bg-subtle);
  border-left: 3px solid var(--accent);
  font-size: 0.95rem;
  line-height: 1.55;
  color: var(--text);
}

.feedback strong {
  display: block;
  margin-bottom: 4px;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
  font-weight: 600;
}

.feedback[data-correct="true"] {
  border-left-color: var(--success);
}

.feedback[data-correct="false"] {
  border-left-color: var(--danger);
}

.q-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-3);
  margin-top: var(--space-6);
  flex-wrap: wrap;
}

/* --- Results screen -------------------------------------------------------- */
.results {
  max-width: 640px;
  margin: 0 auto;
  padding: var(--space-12) var(--space-6) var(--space-20);
  text-align: center;
}

.score-ring {
  width: 180px;
  height: 180px;
  margin: 0 auto var(--space-6);
  position: relative;
}

.score-ring svg {
  transform: rotate(-90deg);
}

.score-ring-bg {
  fill: none;
  stroke: var(--bg-subtle);
  stroke-width: 12;
}

.score-ring-fg {
  fill: none;
  stroke: var(--accent);
  stroke-width: 12;
  stroke-linecap: round;
  transition: stroke-dashoffset 1s var(--ease-out);
}

.score-ring-text {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.score-pct {
  font-size: 2.5rem;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.score-frac {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

.results h2 {
  margin-bottom: var(--space-2);
}

.results-meta {
  color: var(--text-secondary);
  font-size: 1rem;
  margin-bottom: var(--space-6);
}

.breakdown {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  margin: var(--space-6) 0;
  text-align: left;
  overflow: hidden;
}

.breakdown-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-3) var(--space-5);
  border-bottom: 1px solid var(--border);
  font-size: 0.92rem;
}

.breakdown-row:last-child {
  border-bottom: none;
}

.breakdown-row .topic {
  color: var(--text);
}

.breakdown-row .score {
  font-variant-numeric: tabular-nums;
  color: var(--text-secondary);
  font-weight: 500;
}

.results-actions {
  display: flex;
  gap: var(--space-3);
  justify-content: center;
  flex-wrap: wrap;
  margin-top: var(--space-6);
}

/* --- Landing: lecture cards + semester sections -------------------------- */
.lectures {
  padding: var(--space-4) var(--space-6) var(--space-16);
}

.sem-header {
  display: flex;
  align-items: baseline;
  gap: var(--space-3);
  margin: var(--space-6) 0 var(--space-4);
}

.section-h {
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0;
}

.section-h-spaced {
  margin-top: var(--space-12);
  margin-bottom: var(--space-4);
}

.sem-tag {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 3px 8px;
  border-radius: var(--radius-full);
}

.lecture-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: var(--space-4);
}

.lecture-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: var(--space-5);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: var(--text);
  position: relative;
  overflow: hidden;
  transition: transform 200ms var(--ease-out), box-shadow 200ms var(--ease-out),
    border-color 200ms var(--ease-out);
}

.lecture-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
  opacity: 1;
}

.lecture-card-code {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  color: var(--text-tertiary);
}

.lecture-card-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 2px 0 var(--space-2);
  letter-spacing: -0.01em;
  color: var(--text);
}

.lecture-card-meta {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-3);
}

.lect-meta-pct {
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.lect-meta-pct[data-tone="good"] { color: var(--success); }
.lect-meta-pct[data-tone="ok"]   { color: var(--warning); }
.lect-meta-pct[data-tone="weak"] { color: var(--danger); }

.lecture-card-cta {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--accent);
  margin-top: auto;
  align-self: flex-start;
}

.sem-details {
  margin-bottom: var(--space-3);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--bg-elevated);
}

.sem-details summary {
  cursor: pointer;
  padding: var(--space-4) var(--space-5);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  list-style: none;
}

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

.sem-details summary::before {
  content: "▸";
  display: inline-block;
  margin-right: 10px;
  color: var(--text-tertiary);
  transition: transform 150ms ease-out;
  flex-shrink: 0;
}

.sem-details[open] summary::before {
  transform: rotate(90deg);
}

.sem-details summary .sem-label {
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  flex: 1;
}

.sem-details[open] .lecture-grid {
  padding: 0 var(--space-5) var(--space-5);
}

/* --- Page eyebrow used by exam/dashboard pages ---------------------------- */
.page-eyebrow {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: var(--space-2);
}

/* --- Theme toggle: segmented pill in the topnav ------------------------- */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0;
  padding: 3px;
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
}

.theme-toggle-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  padding: 0;
  border-radius: var(--radius-full);
  background: transparent;
  color: var(--text-tertiary);
  border: none;
  cursor: pointer;
  transition: color 120ms ease-out, background-color 120ms ease-out;
}

.theme-toggle-btn:hover {
  color: var(--text-secondary);
}

.theme-toggle-btn[aria-pressed="true"] {
  background: var(--bg-elevated);
  color: var(--text);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.06);
}

[data-theme="dark"] .theme-toggle-btn[aria-pressed="true"],
:root:not([data-theme="light"]) .theme-toggle-btn[aria-pressed="true"] {
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
}

/* --- Topnav: secondary links next to the CTA ------------------------------ */
.topnav-links {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.topnav-link-ghost {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: 7px 4px;
  text-decoration: none;
  transition: color 120ms ease-out;
}

.topnav-link-ghost:hover {
  color: var(--text);
  opacity: 1;
}

.topnav-link-ghost.is-active {
  color: var(--accent);
  background: var(--accent-soft);
  padding: 7px 12px;
  border-radius: var(--radius-full);
  font-weight: 600;
}

/* --- Dashboard: empty state ----------------------------------------------- */
.dash-empty {
  display: flex;
  justify-content: center;
  padding: var(--space-12) var(--space-6) var(--space-20);
}

.dash-empty-card {
  max-width: 480px;
  text-align: center;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-12) var(--space-8);
  box-shadow: var(--shadow-md);
}

.dash-empty-icon {
  font-size: 2rem;
  color: var(--accent);
  margin-bottom: var(--space-3);
}

.dash-empty h2 {
  font-size: 1.4rem;
  margin-bottom: var(--space-2);
}

.dash-empty p {
  color: var(--text-secondary);
  margin-bottom: var(--space-6);
  line-height: 1.5;
}

/* --- Dashboard: filter pills (Alle / grouped by semester) ----------------- */
.filter-pills {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-6) 0;
  margin-bottom: var(--space-2);
}

.filter-pill-section {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.filter-pill-label {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  color: var(--text-tertiary);
  margin: 0;
}

.filter-pill-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.filter-pill {
  display: inline-flex;
  align-items: center;
  padding: 7px 14px;
  font-size: 0.88rem;
  font-weight: 500;
  letter-spacing: -0.005em;
  color: var(--text-secondary);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  text-decoration: none;
  white-space: nowrap;
  transition: background-color 120ms ease-out, color 120ms ease-out, border-color 120ms ease-out;
}

.filter-pill:hover {
  background: var(--bg-subtle);
  color: var(--text);
  border-color: var(--border-strong);
  opacity: 1;
}

.filter-pill.is-active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.filter-pill.is-active:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  color: #fff;
}

/* --- Dashboard: stat cards grid ------------------------------------------- */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--space-3);
  margin-bottom: var(--space-6);
  padding-top: var(--space-4);
}

.stat-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  box-shadow: var(--shadow-sm);
}

.stat-label {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 600;
  color: var(--text-tertiary);
  margin-bottom: var(--space-2);
}

.stat-value {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--text);
}

.stat-sub {
  font-size: 0.82rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

/* --- Dashboard: panels ---------------------------------------------------- */
.panel {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin-bottom: var(--space-6);
  box-shadow: var(--shadow-sm);
}

.panel-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-4);
  margin-bottom: var(--space-5);
  flex-wrap: wrap;
}

.panel-title {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 2px;
}

.panel-sub {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.legend {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
}

/* --- Dashboard: trend chart ----------------------------------------------- */
.chart-container {
  width: 100%;
  overflow-x: auto;
}

#trend-chart {
  width: 100%;
  height: auto;
  min-height: 240px;
}

#trend-chart .grid-line {
  stroke: var(--border);
  stroke-width: 1;
}

#trend-chart .axis-line {
  stroke: var(--border-strong);
  stroke-width: 1;
}

#trend-chart .axis-label {
  fill: var(--text-tertiary);
  font-size: 11px;
  font-family: var(--font-sans);
  font-variant-numeric: tabular-nums;
}

#trend-chart .pass-line {
  stroke: var(--success);
  stroke-width: 1;
  stroke-dasharray: 4 4;
  opacity: 0.55;
}

#trend-chart .pass-label {
  fill: var(--success);
  font-size: 10.5px;
  font-family: var(--font-sans);
  font-weight: 600;
}

#trend-chart .trend-area {
  fill: var(--accent);
  opacity: 0.08;
}

#trend-chart .trend-line {
  fill: none;
  stroke: var(--accent);
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

#trend-chart .trend-dot {
  fill: var(--bg-elevated);
  stroke: var(--accent);
  stroke-width: 2.5;
  cursor: pointer;
  transition: r 120ms ease-out;
}

#trend-chart .trend-dot:hover {
  r: 7;
}

/* --- Dashboard: topic performance bars ------------------------------------ */
.topic-perf-row {
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--border);
}

.topic-perf-row:last-child {
  border-bottom: none;
}

.topic-perf-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-3);
  margin-bottom: 6px;
}

.topic-perf-name-block {
  display: flex;
  flex-direction: column;
  gap: 2px;
  flex: 1;
  min-width: 0;
}

.topic-perf-name {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text);
}

.topic-perf-sub {
  font-size: 0.78rem;
  color: var(--text-tertiary);
  line-height: 1.3;
}

.topic-perf-pct {
  font-size: 0.95rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.topic-perf-pct[data-tone="good"] { color: var(--success); }
.topic-perf-pct[data-tone="ok"]   { color: var(--warning); }
.topic-perf-pct[data-tone="weak"] { color: var(--danger); }

.topic-perf-bar {
  width: 100%;
  height: 6px;
  background: var(--bg-subtle);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-bottom: 4px;
}

.topic-perf-fill {
  height: 100%;
  border-radius: var(--radius-full);
  transition: width 600ms var(--ease-out);
}

.topic-perf-fill[data-tone="good"] { background: var(--success); }
.topic-perf-fill[data-tone="ok"]   { background: var(--warning); }
.topic-perf-fill[data-tone="weak"] { background: var(--danger); }

.topic-perf-meta {
  font-size: 0.78rem;
  color: var(--text-tertiary);
}

/* --- Dashboard: data management panel ------------------------------------- */
.data-actions {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
  margin-bottom: var(--space-3);
}

.data-actions .btn-danger {
  color: var(--danger);
}

.data-actions .btn-danger:hover {
  background: var(--danger-soft);
}

.data-hint {
  font-size: 0.82rem;
  color: var(--text-tertiary);
  line-height: 1.5;
  margin: 0;
}

/* Inline link-style button used in the empty state for "import backup" */
.empty-import {
  margin-top: var(--space-5);
  font-size: 0.88rem;
  color: var(--text-tertiary);
}

.link-btn {
  background: none;
  border: none;
  padding: 0;
  font: inherit;
  color: var(--accent);
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
}

.link-btn:hover {
  text-decoration: underline;
}

/* --- Dashboard: recent exams list ----------------------------------------- */
.recent-row {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--border);
}

.recent-row:last-child {
  border-bottom: none;
}

.recent-pct {
  flex-shrink: 0;
  width: 56px;
  text-align: center;
  font-size: 1.1rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
  padding: 8px 0;
  border-radius: var(--radius-md);
}

.recent-pct[data-tone="good"] { color: var(--success); background: var(--success-soft); }
.recent-pct[data-tone="ok"]   { color: var(--warning); background: rgba(255, 149, 0, 0.12); }
.recent-pct[data-tone="weak"] { color: var(--danger);  background: var(--danger-soft); }

.recent-info {
  flex: 1;
  min-width: 0;
}

.recent-topics {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text);
  margin-bottom: 2px;
  overflow: hidden;
  text-overflow: ellipsis;
}

.recent-topics .tag {
  margin-left: 6px;
  vertical-align: middle;
}

.recent-meta {
  font-size: 0.82rem;
  color: var(--text-secondary);
  font-variant-numeric: tabular-nums;
}

/* --- Empty / loading states ------------------------------------------------ */
.empty-state {
  text-align: center;
  padding: var(--space-12) var(--space-6);
  color: var(--text-secondary);
}

.spinner {
  width: 28px;
  height: 28px;
  border: 3px solid var(--bg-subtle);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto var(--space-3);
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* --- Utility --------------------------------------------------------------- */
.hidden {
  display: none !important;
}

@media (max-width: 600px) {
  .hero {
    padding-top: var(--space-12);
  }
  .q-card {
    padding: var(--space-6);
  }
  .start-bar {
    flex-direction: column;
    align-items: stretch;
  }
  .start-bar .btn {
    width: 100%;
  }
}