:root {
  --bg: #f4f5f3;
  --panel: #ffffff;
  --panel-soft: #f8faf9;
  --ink: #172321;
  --muted: #63716e;
  --line: #dbe4e1;
  --line-strong: #c7d5d1;
  --accent: #17766c;
  --accent-strong: #0e5d55;
  --accent-soft: #e8f4f1;
  --warning: #a85a0b;
  --warning-soft: #fff8e9;
  --danger: #b33434;
  --danger-soft: #fff5f5;
  --input: #ffffff;
  --sticky: rgba(255, 255, 255, 0.96);
  --shadow: none;
  --shadow-small: none;
  --radius: 4px;
  --radius-small: 3px;
}

:root[data-theme="dark"] {
  --bg: #101716;
  --panel: #17211f;
  --panel-soft: #1b2825;
  --ink: #edf4f2;
  --muted: #a5b4b0;
  --line: #2c3a37;
  --line-strong: #40504c;
  --accent: #69cfc1;
  --accent-strong: #91e3d8;
  --accent-soft: #183a34;
  --warning: #f0b35f;
  --warning-soft: #352814;
  --danger: #ff9898;
  --danger-soft: #351e1e;
  --input: #101817;
  --sticky: rgba(23, 33, 31, 0.96);
  --shadow: 0 14px 40px rgba(0, 0, 0, 0.25);
  --shadow-small: 0 5px 18px rgba(0, 0, 0, 0.18);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --bg: #101716;
    --panel: #17211f;
    --panel-soft: #1b2825;
    --ink: #edf4f2;
    --muted: #a5b4b0;
    --line: #2c3a37;
    --line-strong: #40504c;
    --accent: #69cfc1;
    --accent-strong: #91e3d8;
    --accent-soft: #183a34;
    --warning: #f0b35f;
    --warning-soft: #352814;
    --danger: #ff9898;
    --danger-soft: #351e1e;
    --input: #101817;
    --sticky: rgba(23, 33, 31, 0.96);
    --shadow: 0 14px 40px rgba(0, 0, 0, 0.25);
    --shadow-small: 0 5px 18px rgba(0, 0, 0, 0.18);
  }
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  min-height: 100%;
  scroll-behavior: smooth;
}

body {
  min-height: 100%;
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.62 system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Tahoma, Arial, sans-serif;
  transition: background-color 180ms ease, color 180ms ease;
}

button,
input,
textarea {
  font: inherit;
}

button {
  border: 0;
  border-radius: var(--radius-small);
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  font-weight: 750;
  padding: 0.82rem 1.05rem;
  transition: background 150ms ease, border-color 150ms ease, transform 150ms ease;
}

button:hover {
  background: var(--accent-strong);
  transform: translateY(-1px);
}

button:active {
  transform: translateY(0);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.6;
  transform: none;
}

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

.shell {
  width: min(1080px, calc(100% - 32px));
  margin: 0 auto;
  padding: 30px 0 46px;
}

.topbar {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 22px;
  margin-bottom: 22px;
}

.title-group {
  min-width: 0;
}

.eyebrow,
.section-kicker {
  margin: 0 0 5px;
  color: var(--accent);
  font-size: 0.76rem;
  font-weight: 820;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

h1 {
  max-width: 850px;
  margin: 0;
  font-size: clamp(1.65rem, 4vw, 2.55rem);
  font-weight: 760;
  letter-spacing: -0.035em;
  line-height: 1.12;
}

.subtitle {
  max-width: 720px;
  margin: 9px 0 0;
  color: var(--muted);
  font-size: 1.02rem;
}

.window-info {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.top-actions {
  display: grid;
  flex: 0 0 auto;
  justify-items: end;
  gap: 10px;
}

.theme-toggle {
  display: inline-grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--panel);
  box-shadow: var(--shadow-small);
  color: var(--muted);
  padding: 0;
}

.theme-toggle:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.timer {
  min-width: 150px;
  border: 1px solid var(--line);
  border-radius: 3px;
  background: var(--panel);
  box-shadow: var(--shadow-small);
  padding: 12px 15px;
  text-align: right;
}

.timer-label {
  display: block;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 780;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.timer strong {
  display: block;
  margin-top: 1px;
  font-size: 1.75rem;
  font-variant-numeric: tabular-nums;
  line-height: 1.08;
}

.timer.late {
  border-color: color-mix(in srgb, var(--warning), transparent 42%);
  background: var(--warning-soft);
  color: var(--warning);
}

.timer.closed {
  border-color: color-mix(in srgb, var(--danger), transparent 45%);
  background: var(--danger-soft);
  color: var(--danger);
}

.panel,
.notice,
.result-panel {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow);
  animation: rise 220ms ease both;
}

.panel {
  padding: clamp(18px, 3vw, 28px);
}

.panel-heading {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 20px;
}

.panel#loginPanel {
  border-top: 3px solid var(--accent);
}

.panel-heading h2 {
  margin: 0;
  font-size: 1.35rem;
  line-height: 1.25;
}

.panel-heading > p {
  max-width: 470px;
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
  text-align: right;
}

.login-form {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: end;
  gap: 12px;
}

.login-fields {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.input-group {
  display: grid;
  gap: 7px;
}

.input-group > span {
  font-size: 0.88rem;
  font-weight: 760;
}

input[type="text"],
input[type="password"],
textarea {
  width: 100%;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-small);
  background: var(--input);
  color: var(--ink);
  outline: none;
  transition: border-color 150ms ease, box-shadow 150ms ease, background 150ms ease;
}

input[type="text"],
input[type="password"] {
  min-height: 49px;
  padding: 0.78rem 0.9rem;
}

textarea {
  min-height: 130px;
  padding: 0.9rem 1rem;
  line-height: 1.68;
  resize: vertical;
}

input:focus,
textarea:focus,
button:focus-visible,
a:focus-visible {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent), transparent 78%);
  outline: none;
}

.hint,
#submitHint {
  margin: 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.login-form > .hint,
.remembered {
  grid-column: 1 / -1;
}

.remembered {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--muted);
  font-size: 0.9rem;
}

.ghost-button,
.link-button {
  border: 1px solid var(--line);
  background: transparent;
  color: var(--accent-strong);
}

.ghost-button:hover,
.link-button:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.link-button {
  border: 0;
  border-radius: 0;
  padding: 0;
  font-size: 0.9rem;
}

.link-button:hover {
  background: transparent;
  text-decoration: underline;
  transform: none;
}

.notice {
  margin-bottom: 18px;
  padding: 14px 16px;
  color: var(--muted);
}

.live-update {
  display: flex;
  gap: 8px;
  border-left: 3px solid var(--warning);
  background: var(--warning-soft);
  margin-bottom: 18px;
  padding: 11px 14px;
  color: var(--ink);
}

.live-update strong {
  flex: 0 0 auto;
  color: var(--warning);
}

.notice.error {
  border-color: color-mix(in srgb, var(--danger), transparent 55%);
  background: var(--danger-soft);
  color: var(--danger);
}

.notice.success {
  border-color: color-mix(in srgb, var(--accent), transparent 55%);
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.result-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
  padding: 16px 18px;
}

.after-panel {
  border-top: 3px solid var(--accent);
  background: var(--panel);
  margin-bottom: 18px;
  padding: 22px clamp(18px, 3vw, 28px);
}

.after-panel h2 {
  margin: 0 0 10px;
  font-size: 1.35rem;
}

.after-panel p {
  max-width: 850px;
  margin: 7px 0;
  color: var(--muted);
}

.feedback-link {
  display: inline-block;
  border-bottom: 1px solid currentColor;
  margin-top: 10px;
  color: var(--accent-strong);
  font-weight: 760;
  text-decoration: none;
}

.feedback-link:hover {
  border-bottom-width: 2px;
}

.feedback-note {
  font-size: 0.82rem;
}

.result-panel p {
  margin: 3px 0 0;
  color: var(--muted);
}

.result-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 9px;
}

.report-button {
  border-radius: var(--radius-small);
  background: var(--accent);
  color: #fff;
  padding: 0.72rem 0.9rem;
  font-weight: 760;
  text-decoration: none;
  white-space: nowrap;
}

.toast {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 30;
  max-width: min(380px, calc(100vw - 36px));
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--panel);
  box-shadow: var(--shadow);
  color: var(--ink);
  padding: 12px 15px;
  font-weight: 720;
  animation: toast-in 180ms ease both;
}

.toast.success {
  border-color: color-mix(in srgb, var(--accent), transparent 55%);
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.toast.error {
  border-color: color-mix(in srgb, var(--danger), transparent 50%);
  color: var(--danger);
}

.quiz-meta {
  display: grid;
  grid-template-columns: 1.35fr 0.75fr 1fr;
  gap: 0;
  border-block: 1px solid var(--line);
  margin-bottom: 22px;
}

.quiz-meta > div {
  min-width: 0;
  border: 0;
  border-right: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
  padding: 10px 14px;
}

.quiz-meta > div:last-child {
  border-right: 0;
}

.label {
  display: block;
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 790;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.quiz-meta strong {
  display: block;
  overflow: hidden;
  margin-top: 2px;
  font-size: 0.91rem;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#saveStatus[data-tone="success"] {
  color: var(--accent-strong);
}

#saveStatus[data-tone="warning"] {
  color: var(--warning);
}

.instructions {
  display: grid;
  gap: 7px;
  border-left: 3px solid var(--accent);
  margin-bottom: 16px;
  padding: 2px 0 2px 15px;
  color: var(--muted);
}

.instructions p {
  margin: 0;
}

.integrity-notice {
  border: 0;
  border-left: 2px solid var(--line-strong);
  border-radius: 0;
  background: transparent;
  margin: 15px 0;
  padding: 13px 15px;
}

.integrity-notice strong {
  display: block;
  font-size: 0.86rem;
}

.integrity-notice p {
  margin: 3px 0 0;
  color: var(--muted);
  font-size: 0.86rem;
}

.resources {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  margin: 18px 0 24px;
}

.resource-download {
  border: 1px solid var(--accent);
  border-radius: 3px;
  background: var(--accent-soft);
  padding: 0.45rem 0.72rem;
  font-size: 0.86rem;
  font-weight: 760;
  text-decoration: none;
}

.reference-library {
  position: relative;
  font-size: 0.86rem;
}

.reference-library summary {
  color: var(--accent-strong);
  cursor: pointer;
  font-weight: 700;
}

.reference-links {
  display: grid;
  gap: 7px;
  border-left: 2px solid var(--line);
  margin-top: 10px;
  padding-left: 12px;
}

.reference-links a {
  width: fit-content;
  text-decoration: none;
}

.reference-links a:hover {
  text-decoration: underline;
}

.source-link {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 3px;
  color: var(--accent-strong);
  padding: 0.34rem 0.7rem;
  font-size: 0.86rem;
  font-weight: 680;
  text-decoration: none;
}

.source-link:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
}

#questions {
  display: grid;
  gap: 20px;
}

.question {
  border: 0;
  border-top: 3px solid var(--ink);
  border-radius: 0;
  background: var(--panel);
  overflow: clip;
}

.question-header {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 13px;
  border-bottom: 1px solid var(--line);
  background: var(--panel);
  padding: 18px clamp(16px, 3vw, 24px);
}

.question-number {
  display: inline-grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 0;
  background: transparent;
  color: var(--accent-strong);
  font-size: 0.78rem;
  font-weight: 820;
  font-variant-numeric: tabular-nums;
}

.question h2 {
  margin: 0;
  font-size: clamp(1.05rem, 2.2vw, 1.28rem);
  line-height: 1.38;
}

.question-prompt {
  margin: 3px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.question-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 9px;
}

.question-chips span {
  border: 0;
  border-right: 1px solid var(--line);
  border-radius: 0;
  background: transparent;
  color: var(--muted);
  padding: 0.15rem 0.54rem;
  font-size: 0.75rem;
  font-weight: 690;
}

.question-body {
  display: grid;
  gap: 14px;
  padding: 22px clamp(16px, 3vw, 24px);
}

.question-body > * {
  margin-top: 0;
  margin-bottom: 0;
}

.prompt-paragraph {
  color: var(--ink);
}

.block-heading {
  margin-top: 8px;
  font-size: 1rem;
}

.question-body ul,
.question-body ol {
  margin: 0;
  padding-inline-start: 1.45rem;
}

.question-body li + li {
  margin-top: 6px;
}

.task-block {
  border: 0;
  border-left: 3px solid var(--accent);
  border-radius: 0;
  background: var(--panel-soft);
  padding: 15px 16px;
}

.task-block > strong {
  display: block;
  margin-bottom: 7px;
  color: var(--accent-strong);
  font-size: 0.85rem;
}

.table-scroll {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 0;
  -webkit-overflow-scrolling: touch;
}

table {
  width: 100%;
  min-width: 510px;
  border-collapse: collapse;
  font-size: 0.91rem;
  font-variant-numeric: tabular-nums;
}

th,
td {
  border-bottom: 1px solid var(--line);
  padding: 9px 12px;
  text-align: left;
}

th {
  background: var(--panel-soft);
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 780;
  letter-spacing: 0.02em;
}

tbody tr:last-child td {
  border-bottom: 0;
}

tbody tr:nth-child(even) {
  background: color-mix(in srgb, var(--panel-soft), transparent 35%);
}

.formula {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 0;
  background: var(--panel-soft);
  padding: 12px 15px;
  text-align: center;
}

.katex-display {
  margin: 0.2em 0 !important;
}

.callout {
  border-left: 3px solid var(--accent);
  border-radius: 0;
  background: var(--accent-soft);
  padding: 12px 14px;
  color: var(--ink);
}

.rule-box {
  border-left: 3px solid #66837e;
  background: color-mix(in srgb, var(--accent-soft), transparent 35%);
  padding: 13px 15px;
}

.rule-box > strong {
  display: block;
  margin-bottom: 6px;
  color: var(--accent-strong);
  font-size: 0.84rem;
}

.rule-box ul {
  color: var(--muted);
  font-size: 0.9rem;
}

.source-link {
  width: max-content;
  max-width: 100%;
}

.response-fields {
  display: grid;
  gap: 16px;
  border-top: 1px solid var(--line);
  background: var(--panel);
  padding: 22px clamp(16px, 3vw, 24px) 24px;
}

.answer-field {
  border: 0;
  border-left: 2px solid var(--line-strong);
  border-radius: 0;
  background: transparent;
  padding: 2px 0 2px 14px;
}

.answer-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 4px;
}

.answer-heading label {
  font-weight: 770;
}

.field-points {
  flex: 0 0 auto;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 680;
}

.field-hint {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 0.86rem;
}

.field-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-top: 6px;
  color: var(--muted);
  font-size: 0.76rem;
}

.field-sync {
  color: var(--accent-strong);
}

.field-sync[data-pending="true"] {
  color: var(--warning);
}

.character-count {
  font-variant-numeric: tabular-nums;
}

.field-feedback {
  border-left: 3px solid var(--accent);
  margin: 12px 0 0;
  padding-left: 10px;
  color: var(--muted);
}

.options {
  display: grid;
  gap: 9px;
  padding: 20px clamp(16px, 3vw, 24px);
}

.option {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: start;
  gap: 10px;
  border: 1px solid var(--line);
  border-radius: 2px;
  padding: 11px 12px;
  cursor: pointer;
  transition: background 150ms ease, border-color 150ms ease;
}

.option:hover {
  border-color: var(--line-strong);
  background: var(--panel-soft);
}

.option:has(input:checked) {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.option.correct {
  border-color: var(--accent);
}

.option.wrong {
  border-color: var(--danger);
}

.option input {
  margin-top: 0.33rem;
}

.solution {
  margin: 0 24px 20px;
  color: var(--muted);
  font-size: 0.9rem;
}

.solution.ok {
  color: var(--accent-strong);
}

.solution.no {
  color: var(--danger);
}

.submit-row {
  position: sticky;
  bottom: 12px;
  z-index: 10;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: 15px;
  border: 1px solid var(--line);
  border-radius: 3px;
  background: var(--sticky);
  box-shadow: 0 12px 35px rgba(26, 56, 50, 0.14);
  margin-top: 22px;
  padding: 13px;
  backdrop-filter: blur(10px);
}

#quizPanel {
  border: 0;
  background: transparent;
  box-shadow: none;
  padding: 0;
}

#quizPanel.review-mode .instructions,
#quizPanel.review-mode .integrity-notice,
#quizPanel.review-mode .submit-row {
  display: none;
}

.submit-row strong {
  display: block;
  font-size: 0.9rem;
}

.submit-row p {
  margin-top: 2px;
}

.site-footer {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-top: 22px;
  color: var(--muted);
  font-size: 0.82rem;
}

.site-footer a {
  color: var(--accent-strong);
  text-decoration: none;
}

.site-footer a:hover {
  text-decoration: underline;
}

.session-list {
  margin: 12px 0 0;
  padding-inline-start: 1.2rem;
}

.session-list span {
  color: var(--muted);
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(7px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes toast-in {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 760px) {
  .shell {
    width: min(100% - 20px, 1080px);
    padding-top: 16px;
  }

  .topbar,
  .panel-heading,
  .result-panel {
    display: grid;
  }

  .top-actions {
    grid-template-columns: auto minmax(0, 1fr);
    justify-items: start;
    align-items: center;
  }

  .timer {
    width: 100%;
    text-align: left;
  }

  .panel-heading > p {
    text-align: left;
  }

  .login-form,
  .login-fields,
  .quiz-meta {
    grid-template-columns: 1fr;
  }

  .login-form > button {
    width: 100%;
  }

  .quiz-meta {
    gap: 7px;
  }

  .quiz-meta strong {
    white-space: normal;
  }

  .result-actions {
    justify-content: stretch;
  }

  .report-button,
  .ghost-button {
    text-align: center;
  }

  .submit-row {
    position: static;
    grid-template-columns: 1fr;
  }

  .submit-row button {
    width: 100%;
  }

  .site-footer {
    display: grid;
    gap: 2px;
    text-align: center;
  }
}

@media (max-width: 480px) {
  body {
    font-size: 15px;
  }

  .panel {
    padding: 15px;
  }

  .question-header {
    grid-template-columns: 1fr;
  }

  .question-number {
    width: 31px;
    height: 31px;
  }

  .answer-heading,
  .field-footer {
    align-items: flex-start;
  }

  .toast {
    right: 10px;
    bottom: 10px;
    max-width: calc(100vw - 20px);
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}