:root {
  --bg: #eef4f8;
  --card: #ffffff;
  --text: #17212b;
  --muted: #637282;
  --line: #d9e3ea;
  --brand: #0f6c81;
  --brand-dark: #0a5060;
  --ok: #14804a;
  --ok-bg: #e7f6ee;
  --bad: #bb2f2a;
  --bad-bg: #fdeceb;
  --warn: #9b6a00;
  --warn-bg: #fff6db;
  --shadow: 0 20px 50px rgba(24, 49, 67, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(15, 108, 129, 0.18), transparent 34rem),
    linear-gradient(135deg, #f8fbfd, var(--bg));
  font-family:
    Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
}

button,
.file-button,
.link-button {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 12px 14px;
  color: var(--text);
  background: #fff;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  text-align: center;
  text-decoration: none;
  touch-action: manipulation;
  transition:
    transform 0.16s ease,
    border-color 0.16s ease,
    background 0.16s ease;
}

button:hover,
.file-button:hover,
.link-button:hover {
  transform: translateY(-1px);
  border-color: var(--brand);
}

button.primary {
  color: #fff;
  border-color: var(--brand);
  background: var(--brand);
}

button.primary:hover {
  background: var(--brand-dark);
}

button.danger {
  color: var(--bad);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
  transform: none;
}

.hero {
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: 24px;
  max-width: 1180px;
  margin: 0 auto;
  padding: 48px 24px 24px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--brand);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(32px, 5vw, 56px);
  line-height: 1;
}

.subtitle {
  max-width: 680px;
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.5;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.hero-actions button,
.hero-actions .link-button {
  width: auto;
  min-width: 160px;
}

.hero-card {
  display: grid;
  min-width: 170px;
  border: 1px solid rgba(255, 255, 255, 0.7);
  border-radius: 24px;
  padding: 22px;
  background: rgba(255, 255, 255, 0.72);
  box-shadow: var(--shadow);
  place-items: center;
}

.hero-card span {
  color: var(--muted);
  font-weight: 700;
}

.hero-card strong {
  color: var(--brand);
  font-size: 52px;
  line-height: 1;
}

.layout {
  display: grid;
  gap: 24px;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 24px 48px;
}

.panel,
.question-card {
  border: 1px solid rgba(255, 255, 255, 0.74);
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.88);
  box-shadow: var(--shadow);
}

.sidebar {
  position: sticky;
  top: 20px;
  display: grid;
  align-self: start;
  gap: 12px;
  padding: 18px;
}

.divider {
  height: 1px;
  margin: 6px 0;
  background: var(--line);
}

.toggle {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 800;
  cursor: pointer;
}

.toggle input {
  width: 18px;
  height: 18px;
  accent-color: var(--brand);
}

.key-tools {
  display: none;
  gap: 10px;
}

.key-tools.visible {
  display: grid;
}

.file-button {
  display: block;
  text-align: center;
}

.file-button input {
  display: none;
}

.sidebar h2 {
  margin: 0 0 10px;
  font-size: 16px;
}

.stats {
  display: grid;
  gap: 10px;
  margin: 0;
}

.stats div {
  display: flex;
  justify-content: space-between;
  gap: 12px;
}

.stats dt {
  color: var(--muted);
}

.stats dd {
  margin: 0;
  font-weight: 900;
}

.hint {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.5;
}

.hint p {
  margin: 0 0 10px;
}

.hint a {
  color: var(--brand);
  font-weight: 800;
}

.content {
  display: grid;
  gap: 18px;
}

.result {
  padding: 18px 20px;
  font-weight: 800;
}

.result.ok {
  color: var(--ok);
  background: var(--ok-bg);
}

.result.bad {
  color: var(--bad);
  background: var(--bad-bg);
}

.result.warn {
  color: var(--warn);
  background: var(--warn-bg);
}

.question-list {
  display: grid;
  gap: 18px;
}

.question-card {
  padding: 22px;
}

.question-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
}

.question-number,
.key-status {
  display: inline-flex;
  align-items: center;
  border-radius: 999px;
  padding: 6px 10px;
  font-size: 13px;
  font-weight: 900;
}

.question-number {
  color: #fff;
  background: var(--brand);
}

.key-status {
  color: var(--warn);
  background: var(--warn-bg);
}

.key-status.ready {
  color: var(--ok);
  background: var(--ok-bg);
}

.question-text {
  margin: 0 0 16px;
  font-size: 22px;
  line-height: 1.35;
}

.image-list {
  display: grid;
  gap: 12px;
  margin-bottom: 16px;
}

.question-image {
  display: block;
  width: auto;
  height: auto;
  max-width: 100%;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #f8fafc;
}

.options {
  display: grid;
  gap: 10px;
}

.option {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 13px 14px;
  background: #fff;
  cursor: pointer;
}

.option.locked {
  cursor: default;
}

.option input {
  flex: 0 0 auto;
  width: 18px;
  height: 18px;
  margin-top: 2px;
  accent-color: var(--brand);
}

.option input:disabled {
  cursor: default;
}

.option.correct {
  border-color: rgba(20, 128, 74, 0.45);
  background: var(--ok-bg);
}

.option.wrong {
  border-color: rgba(187, 47, 42, 0.4);
  background: var(--bad-bg);
}

.question-actions {
  display: none;
  margin-top: 14px;
}

.key-mode .question-actions {
  display: block;
}

.feedback {
  min-height: 22px;
  margin: 12px 0 0;
  color: var(--muted);
  font-weight: 700;
}

.feedback.ok {
  color: var(--ok);
}

.feedback.bad {
  color: var(--bad);
}

.feedback.warn {
  color: var(--warn);
}

.finish-overlay {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  padding: 24px;
  background: rgba(7, 24, 34, 0.68);
  backdrop-filter: blur(8px);
  place-items: center;
}

.finish-overlay[hidden] {
  display: none;
}

.finish-card {
  width: min(620px, 100%);
  border: 1px solid rgba(255, 255, 255, 0.8);
  border-radius: 34px;
  padding: clamp(28px, 7vw, 56px);
  background: #fff;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.3);
  text-align: center;
}

.finish-card h2 {
  margin: 6px 0 14px;
  font-size: clamp(64px, 13vw, 132px);
  line-height: 0.9;
}

.finish-card.ok h2 {
  color: var(--ok);
}

.finish-card.bad h2 {
  color: var(--bad);
}

.finish-card p:not(.eyebrow) {
  margin: 0 0 24px;
  color: var(--muted);
  font-size: 20px;
  font-weight: 800;
}

.finish-card button {
  max-width: 260px;
}

@media (max-width: 860px) {
  .hero {
    flex-direction: column;
    padding-top: 28px;
  }

  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
  }
}

@media (max-width: 700px) {
  body {
    background:
      radial-gradient(circle at top left, rgba(15, 108, 129, 0.16), transparent 22rem),
      linear-gradient(135deg, #f8fbfd, var(--bg));
  }

  .hero {
    gap: 14px;
    padding: 22px 12px 14px;
  }

  .eyebrow {
    margin-bottom: 6px;
    font-size: 11px;
  }

  h1 {
    font-size: clamp(30px, 11vw, 44px);
  }

  .subtitle {
    margin-top: 10px;
    font-size: 15px;
    line-height: 1.4;
  }

  .hero-actions {
    display: grid;
    grid-template-columns: 1fr;
    gap: 10px;
    margin-top: 16px;
  }

  .hero-actions button,
  .hero-actions .link-button {
    width: 100%;
    min-width: 0;
    padding: 13px 12px;
  }

  .hero-card {
    display: flex;
    min-width: 0;
    align-items: center;
    justify-content: space-between;
    border-radius: 18px;
    padding: 12px 16px;
  }

  .hero-card strong {
    font-size: 36px;
  }

  .layout {
    gap: 14px;
    padding: 0 10px 28px;
  }

  .content,
  .question-list {
    gap: 12px;
  }

  .question-card {
    border-radius: 18px;
    padding: 14px;
    box-shadow: 0 12px 30px rgba(24, 49, 67, 0.1);
  }

  .question-head {
    margin-bottom: 10px;
  }

  .question-number {
    padding: 5px 9px;
    font-size: 12px;
  }

  .question-text {
    margin-bottom: 12px;
    font-size: 18px;
    line-height: 1.32;
  }

  .image-list {
    gap: 8px;
    margin-bottom: 12px;
  }

  .question-image {
    border-radius: 14px;
  }

  .options {
    gap: 9px;
  }

  .option {
    min-height: 54px;
    gap: 11px;
    border-radius: 14px;
    padding: 14px 12px;
    font-size: 15px;
    line-height: 1.35;
  }

  .option input {
    width: 22px;
    height: 22px;
    margin-top: 0;
  }

  .feedback {
    min-height: 20px;
    margin-top: 10px;
    font-size: 14px;
    line-height: 1.35;
  }

  .finish-overlay {
    align-items: end;
    padding: 12px;
  }

  .finish-card {
    border-radius: 26px;
    padding: 28px 18px 18px;
  }

  .finish-card h2 {
    margin-bottom: 12px;
    font-size: clamp(52px, 18vw, 86px);
  }

  .finish-card p:not(.eyebrow) {
    margin-bottom: 18px;
    font-size: 17px;
  }

  .finish-card button {
    width: 100%;
    max-width: none;
    padding: 15px 16px;
  }
}

@media (max-width: 420px) {
  .hero {
    padding-inline: 10px;
  }

  .hero-actions {
    grid-template-columns: 1fr;
  }

  .hero-card {
    align-items: flex-start;
  }

  .layout {
    padding-inline: 8px;
  }

  .question-card {
    padding: 12px;
  }

  .question-text {
    font-size: 17px;
  }

  .option {
    padding: 13px 11px;
    font-size: 14px;
  }
}