/* Examlearn hosted UI stylesheet (ux-implementation-brief.md section 2 and 5).
   Same-origin only: no external hosts and no imported sheets. Light tokens on :root; the
   dark palette applies with the OS preference unless data-theme="light", or
   explicitly with data-theme="dark". */

/* Self-hosted OFL fonts (latin subset); licenses ship next to the files. */
@font-face {
  font-family: "Fraunces";
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url("/assets/fonts/fraunces-500.woff2") format("woff2");
}

@font-face {
  font-family: "Fraunces";
  font-style: italic;
  font-weight: 500;
  font-display: swap;
  src: url("/assets/fonts/fraunces-500-italic.woff2") format("woff2");
}

@font-face {
  font-family: "Inter";
  font-style: normal;
  font-weight: 400 700;
  font-display: swap;
  src: url("/assets/fonts/inter-variable.woff2") format("woff2");
}

@font-face {
  font-family: "JetBrains Mono";
  font-style: normal;
  font-weight: 400 500;
  font-display: swap;
  src: url("/assets/fonts/jetbrains-mono-variable.woff2") format("woff2");
}

:root {
  color-scheme: light;

  --bg: #ece7dc;
  --paper: #f8f5ee;
  --paper-sunk: #e4dfd3;
  --ink: #1b1d20;
  --ink-soft: #4e525a;
  --ink-faint: #8a8d92;
  --rule: #c9c3b4;
  --rule-strong: #a19a86;

  --ai103: #2d6a62;
  --ai103-soft: #d8e8e4;
  --dp300: #b56536;
  --dp300-soft: #f3e3d3;
  --az104: #1f3b6b;
  --az204: #7d4a9c;
  --az305: #a04040;
  --az900: #5b6b50;

  --ok: #3a7a4a;
  --warn: #8f6b1a;
  --crit: #99364a;
  --accent: #1f3b6b;

  --font-display: "Fraunces", Georgia, serif;
  --font-ui: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "SF Mono", Menlo, Consolas, monospace;

  --radius-utility: 4px;
  --radius-card: 10px;
  --gutter: 16px;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #121316;
    --paper: #1c1e22;
    --paper-sunk: #0e0f12;
    --ink: #ecebe6;
    --ink-soft: #b5b7bc;
    --ink-faint: #7a7d84;
    --rule: #2b2e34;
    --rule-strong: #44484f;
    --ai103: #7cc0b6;
    --ai103-soft: #1a2e2b;
    --dp300: #e2975f;
    --dp300-soft: #3a2616;
    --az104: #a7c0f0;
    --az204: #c89fe4;
    --az305: #e59090;
    --az900: #a8b89a;
    --ok: #7fc08f;
    --warn: #d9b05c;
    --crit: #e18597;
    --accent: #a7c0f0;
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #121316;
  --paper: #1c1e22;
  --paper-sunk: #0e0f12;
  --ink: #ecebe6;
  --ink-soft: #b5b7bc;
  --ink-faint: #7a7d84;
  --rule: #2b2e34;
  --rule-strong: #44484f;
  --ai103: #7cc0b6;
  --ai103-soft: #1a2e2b;
  --dp300: #e2975f;
  --dp300-soft: #3a2616;
  --az104: #a7c0f0;
  --az204: #c89fe4;
  --az305: #e59090;
  --az900: #a8b89a;
  --ok: #7fc08f;
  --warn: #d9b05c;
  --crit: #e18597;
  --accent: #a7c0f0;
}

/* ---- base ---------------------------------------------------------------- */

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: 15px;
  line-height: 1.55;
}

main {
  max-width: 65ch;
  margin-inline: auto;
  padding-inline: max(var(--gutter), env(safe-area-inset-left));
  padding-block: 24px 40px;
}

h1,
h2,
h3 {
  font-family: var(--font-display);
  font-weight: 500;
  letter-spacing: -0.01em;
  line-height: 1.15;
}

code,
kbd,
.mono {
  font-family: var(--font-mono);
}

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

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

button,
select {
  border: 1px solid var(--rule-strong);
  border-radius: var(--radius-utility);
  background: var(--paper);
  padding: 6px 12px;
  cursor: pointer;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.6;
}

input,
textarea {
  border: 1px solid var(--rule);
  border-radius: var(--radius-utility);
  background: var(--paper-sunk);
  padding: 8px 10px;
}

/* Brief section 5: visible focus on every interactive element. */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Brief section 5: number columns use tabular figures. */
.num,
time,
progress,
.count {
  font-variant-numeric: tabular-nums;
}

.status {
  font-size: 1.05rem;
  color: var(--ink-soft);
}

.error {
  color: var(--crit);
}

.muted {
  color: var(--ink-faint);
}

/* ---- login (brief screen 1) ---------------------------------------------- */

main[data-state="login"] {
  max-width: 420px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

main[data-state="login"] > h1 {
  display: none;
}

.brand-name {
  display: block;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 20px;
  letter-spacing: -0.01em;
}

.eyebrow {
  display: block;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.login-hero h2 {
  font-size: 28px;
  margin: 40px 0 10px;
}

.lede {
  color: var(--ink-soft);
  font-size: 14px;
  margin: 0 0 24px;
}

.field-label {
  display: block;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 6px;
}

.input-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--paper-sunk);
  border: 1px solid var(--rule);
  border-radius: var(--radius-card);
  padding: 4px 6px 4px 14px;
  font-family: var(--font-mono);
  font-size: 13px;
}

.input-wrap:focus-within {
  border-color: var(--accent);
}

.input-wrap .prefix {
  color: var(--ink-faint);
}

.input-wrap input {
  flex: 1;
  min-width: 0;
  border: 0;
  background: transparent;
  padding: 8px 0;
  font-family: var(--font-mono);
  letter-spacing: 0.02em;
}

.input-wrap .eye {
  border: 0;
  background: transparent;
  color: var(--ink-faint);
  font-family: var(--font-mono);
  font-size: 12px;
}

.help {
  font-size: 12px;
  color: var(--ink-faint);
  margin: 8px 0 16px;
}

.btn-primary {
  display: block;
  width: 100%;
  border: 0;
  border-radius: var(--radius-card);
  background: var(--ink);
  color: var(--paper);
  padding: 14px;
  font-weight: 600;
  font-size: 14px;
}

.login-foot {
  font-size: 12px;
  color: var(--ink-faint);
  text-align: center;
  border-top: 1px solid var(--rule);
  padding-top: 20px;
  margin-top: 24px;
}

/* ---- home picker (brief screen 2, S4) ------------------------------------ */

main[data-state="home"] {
  max-width: 520px;
}

.picker-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
}

.picker-brand {
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.picker-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--rule-strong);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 12px;
}

.picker-h {
  font-size: 24px;
  margin: 0 0 4px;
}

.picker-sub {
  margin: 0 0 16px;
  color: var(--ink-soft);
}

.exam-stack {
  display: grid;
  gap: 12px;
}

.exam-card {
  position: relative;
  display: grid;
  gap: 9px;
  padding: 14px 14px 14px 16px;
  text-decoration: none;
  color: inherit;
  border-radius: 14px;
  border: 1px solid var(--rule);
  background: var(--paper);
}

.exam-stripe {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  border-radius: 14px 0 0 14px;
  background: var(--accent);
}

.exam-hue-ai103 {
  --exam-hue: var(--ai103);
}

.exam-hue-dp300 {
  --exam-hue: var(--dp300);
}

.exam-hue-accent {
  --exam-hue: var(--accent);
}

.exam-hue-ai103 .exam-stripe,
.exam-hue-dp300 .exam-stripe,
.exam-hue-accent .exam-stripe {
  background: var(--exam-hue);
}

.exam-meta,
.resume-line {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 8px;
}

.exam-code,
.exam-last,
.exam-label,
.resume-line {
  font-family: var(--font-mono);
  font-size: 11px;
}

.exam-code {
  color: var(--exam-hue, var(--ink));
}

.exam-last,
.exam-label,
.resume-line {
  color: var(--ink-faint);
}

.exam-title {
  margin: 0;
  font-size: 18px;
}

.exam-numbers {
  display: flex;
  gap: 20px;
}

.exam-stat b {
  display: block;
  font-size: 17px;
}

.progress-bar {
  width: 100%;
  height: 4px;
}

progress.progress-bar {
  appearance: none;
  border: 0;
  border-radius: 999px;
  overflow: hidden;
  background: var(--paper-sunk);
}

progress.progress-bar::-webkit-progress-bar {
  background: var(--paper-sunk);
}

progress.progress-bar::-webkit-progress-value,
progress.progress-bar::-moz-progress-bar {
  background: var(--exam-hue, var(--accent));
}

.resume-go {
  text-transform: lowercase;
}

.exam-card-item {
  display: grid;
  gap: 4px;
  margin-bottom: 12px;
}

.exam-card-item > .exam-card {
  margin-bottom: 0;
}

.exam-progress-shortcut {
  justify-self: end;
  border: 0;
  background: transparent;
  padding: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  text-transform: lowercase;
  color: var(--accent);
}

/* ---- bottom tabs (home + progress) --------------------------------------- */

.tab-bar {
  position: sticky;
  bottom: 0;
  z-index: 3;
  margin-top: 16px;
  margin-bottom: env(safe-area-inset-bottom);
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 4px;
  border: 1px solid var(--rule);
  border-radius: 12px;
  background: var(--paper);
  padding: 6px;
}

.tab-item {
  text-decoration: none;
  text-align: center;
  border-radius: 8px;
  padding: 8px 6px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.tab-item-active {
  background: color-mix(in srgb, var(--accent) 16%, var(--paper));
  color: var(--ink);
}

.tab-item-disabled {
  opacity: 0.7;
  cursor: not-allowed;
}

/* ---- progress (brief screen 4) ------------------------------------------- */

main[data-state="progress"] {
  max-width: 520px;
}

.progress-back {
  border: 0;
  padding: 0;
  background: transparent;
  color: var(--ink-soft);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.progress-heading {
  margin: 0 0 4px;
  font-size: 24px;
}

.progress-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin: 14px 0;
}

.progress-stat {
  border: 1px solid var(--rule);
  border-radius: 12px;
  padding: 10px 12px;
  background: var(--paper);
}

.progress-stat-value {
  font-size: 28px;
  line-height: 1;
  font-family: var(--font-display);
  font-weight: 500;
}

.progress-stat-label {
  margin-top: 6px;
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.obj-list {
  border: 1px solid var(--rule);
  border-radius: 12px;
  padding: 12px;
  background: var(--paper);
}

.obj-title {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.obj-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  align-items: center;
  padding: 8px 0;
  border-bottom: 1px solid var(--rule);
}

.obj-row:last-child {
  border-bottom: 0;
}

.obj-name {
  min-width: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  font-size: 13px;
}

.obj-score {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 12px;
}

.obj-mini-bar {
  width: 50px;
  height: 4px;
  appearance: none;
  border: 0;
  border-radius: 2px;
  overflow: hidden;
  background: var(--paper-sunk);
}

.obj-mini-bar::-webkit-progress-bar {
  background: var(--paper-sunk);
}

.obj-mini-bar::-webkit-progress-value,
.obj-mini-bar::-moz-progress-bar {
  background: var(--dp300);
}

.obj-row.weak .obj-mini-bar::-webkit-progress-value,
.obj-row.weak .obj-mini-bar::-moz-progress-bar,
.obj-row.weak .obj-value,
.obj-row.weak .obj-weak-tag {
  color: var(--crit);
  background: var(--crit);
}

.obj-row.weak .obj-value,
.obj-row.weak .obj-weak-tag {
  background: transparent;
}

.obj-weak-tag {
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 10px;
}

.progress-cta {
  margin-top: 14px;
}

/* ---- study affordance ----------------------------------------------------- */

#btn-home {
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 11px;
}

.session-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin: 10px 0;
  font-size: 11px;
  color: var(--ink-faint);
}

.session-close {
  font-family: var(--font-ui);
  font-size: 20px;
  line-height: 1;
  padding: 0 10px;
}

.objective-chip {
  display: inline-block;
  width: fit-content;
  border-radius: 999px;
  border: 1px solid color-mix(in srgb, var(--exam-hue, var(--accent)) 35%, var(--rule));
  padding: 3px 10px;
  margin: 6px 0 10px;
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--exam-hue, var(--accent));
  background: color-mix(in srgb, var(--exam-hue, var(--accent)) 14%, var(--paper));
}

.objective-chip.ungradable {
  border-style: dashed;
  border-color: color-mix(in srgb, var(--warn) 50%, var(--rule));
  color: var(--warn);
  background: color-mix(in srgb, var(--warn) 12%, var(--paper));
}

.study-question {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 500;
  line-height: 1.35;
  color: var(--ink);
}

.option-row {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 12px;
  border: 1px solid var(--rule);
  border-radius: var(--radius-card);
  background: var(--paper-sunk);
  margin: 8px 0;
}

.option-letter {
  min-width: 1.2rem;
  font-size: 12px;
  color: var(--ink-faint);
}

.option-row.option-selected {
  border-color: var(--exam-hue, var(--accent));
  background: color-mix(in srgb, var(--exam-hue, var(--accent)) 14%, var(--paper));
}

.option-row.option-correct {
  border-color: var(--ok);
  background: color-mix(in srgb, var(--ok) 14%, var(--paper));
}

.verdict-strip {
  border-radius: var(--radius-card);
  border: 1px solid var(--rule);
  padding: 10px 12px;
  margin-top: 10px;
}

.verdict-strip.ok {
  border-color: color-mix(in srgb, var(--ok) 45%, var(--rule));
  background: color-mix(in srgb, var(--ok) 14%, var(--paper));
}

.verdict-strip.crit {
  border-color: color-mix(in srgb, var(--crit) 45%, var(--rule));
  background: color-mix(in srgb, var(--crit) 10%, var(--paper));
}

.verdict-strip.warn {
  border-color: color-mix(in srgb, var(--warn) 45%, var(--rule));
  background: color-mix(in srgb, var(--warn) 10%, var(--paper));
}

.expected-answer {
  margin-top: 10px;
  padding: 8px 12px;
  border-radius: var(--radius-utility);
  border: 1px dashed var(--rule);
  background: color-mix(in srgb, var(--paper-sunk) 75%, transparent);
}

.audio-dock {
  position: sticky;
  bottom: 0;
  z-index: 2;
  margin-top: 14px;
  margin-bottom: env(safe-area-inset-bottom);
  padding: 10px 12px;
  border-radius: 12px;
  border: 1px solid var(--rule);
  background: var(--paper);
  display: flex;
  align-items: center;
  gap: 10px;
}

.audio-dock-eyebrow {
  font-size: 10px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

.audio-dock-title {
  font-weight: 600;
}

.audio-dock-meta {
  min-width: 0;
  flex: 1;
}

.audio-dock-duration {
  color: var(--ink-faint);
  font-size: 11px;
}

/* Brief section 5: respect reduced motion. */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}