:root {
  --paper: rgba(255, 251, 244, 0.82);
  --paper-strong: #fffaf1;
  --line: #d2c3a5;
  --shadow: 0 18px 50px rgba(92, 61, 28, 0.12);
}

.page-shell {
  width: min(1200px, calc(100% - 32px));
  margin: 0 auto;
  padding: 20px 0 40px;
}

.page {
  display: grid;
  gap: 22px;
}

.hero,
.viewer,
.steps {
  background: var(--paper);
  backdrop-filter: blur(14px);
  border: 1px solid rgba(210, 195, 165, 0.7);
  border-radius: 28px;
  box-shadow: var(--shadow);
}

.hero {
  display: block;
  padding: 30px 32px;
}

.hero__title {
  font-size: clamp(1.95rem, 4vw, 3.2rem);
  max-width: 18ch;
}

.hero__lead,
.hero__note p,
.step-card p,
.keyboard-tip,
.steps__list li p,
.hero__chips li,
.section-copy {
  line-height: 1.65;
}

.hero__lead {
  margin: 18px 0 0;
  max-width: 68ch;
  color: var(--ink-700);
  font-size: 1.04rem;
}

.hero__actions {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 24px;
}

.hero__chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.hero__chips li {
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(255, 250, 241, 0.82);
  border: 1px solid rgba(210, 195, 165, 0.76);
  color: var(--ink-700);
  font-size: 0.9rem;
  font-weight: 700;
}

.ghost-button,
.nav-button {
  border: none;
  border-radius: 999px;
  font: inherit;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.ghost-button {
  min-height: 50px;
  padding: 14px 20px;
  background: var(--accent);
  color: white;
  font-weight: 800;
  box-shadow: 0 12px 24px rgba(189, 93, 56, 0.26);
}

.ghost-button:hover,
.nav-button:hover {
  transform: translateY(-2px);
}

.text-link {
  display: inline-flex;
  align-items: center;
  min-height: 46px;
  padding: 10px 16px;
  border-radius: 999px;
  border: 1px solid rgba(210, 195, 165, 0.82);
  background: rgba(255, 252, 246, 0.72);
  color: var(--accent-deep);
  font-weight: 700;
  text-decoration: none;
}

.hero__note {
  display: grid;
  gap: 18px;
  align-content: start;
  padding: 22px;
  border-radius: 24px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.76), rgba(255, 248, 235, 0.92));
  border: 1px solid rgba(210, 195, 165, 0.7);
}

.hero__note h2 {
  font-size: 1.4rem;
  margin-bottom: 12px;
}

.hero__note p {
  margin: 0;
}

.hero__aside {
  padding-top: 6px;
}

.hero__stat {
  padding: 16px 18px;
  border-radius: 20px;
  background: rgba(255, 250, 241, 0.82);
  border: 1px solid rgba(210, 195, 165, 0.72);
}

.hero__stat strong {
  display: block;
  margin-bottom: 6px;
}

.hero__stat p {
  margin: 0;
  color: var(--ink-700);
}

.viewer {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(320px, 0.85fr);
  grid-template-areas:
    "board panel"
    "board controls";
  gap: 24px;
  padding: 22px;
  align-items: start;
}

.viewer__board,
.step-card {
  background: var(--paper-strong);
  border: 1px solid rgba(210, 195, 165, 0.7);
  border-radius: 24px;
}

.viewer__board {
  grid-area: board;
  padding: 18px;
}

.board-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 14px;
}

.board-header__step {
  min-width: 88px;
  margin: 0;
  color: var(--accent-deep);
  font-weight: 800;
}

.progress {
  flex: 1;
  height: 10px;
  border-radius: 999px;
  background: #eadcc2;
  overflow: hidden;
}

.progress__bar {
  height: 100%;
  width: 0;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--sky), var(--accent));
  transition: width 0.3s ease;
}

.board {
  aspect-ratio: 4 / 3;
  width: 100%;
  overflow: hidden;
  border-radius: 18px;
  background: linear-gradient(180deg, rgba(255, 254, 251, 0.85), rgba(248, 242, 230, 0.95));
}

.board svg {
  display: block;
  width: 100%;
  height: 100%;
}

.viewer__panel {
  grid-area: panel;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.viewer__controls {
  grid-area: controls;
  display: flex;
}

.step-card {
  padding: 22px;
}

.step-card__part {
  margin: 0 0 8px;
  color: var(--sky);
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.76rem;
}

.step-card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 14px;
}

.step-chip {
  padding: 7px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-deep);
  font-size: 0.86rem;
  font-weight: 800;
}

.step-card h2 {
  margin-bottom: 12px;
  font-size: 1.8rem;
}

.step-card p {
  margin: 0;
}

.step-card__hint {
  min-height: 52px;
  margin: 16px 0 0;
  padding: 14px 16px;
  border-radius: 18px;
  background: var(--accent-soft);
  color: var(--accent-deep);
}

.step-card__hint:empty {
  display: none;
}

.controls {
  display: flex;
  gap: 12px;
}

.nav-button {
  flex: 1;
  min-height: 50px;
  padding: 14px 18px;
  background: #ece0cb;
  color: var(--ink-900);
  font-weight: 800;
}

.nav-button--primary {
  background: var(--accent);
  color: white;
}

.nav-button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
}

.keyboard-tip {
  margin: 0;
  color: var(--ink-500);
  text-align: center;
}

.steps {
  padding: 26px;
}

.steps__header {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 18px;
}

.steps__header h2 {
  font-size: clamp(1.8rem, 3vw, 2.5rem);
}

.steps__header p {
  margin: 0;
  color: var(--ink-700);
}

.steps__list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.steps__list li {
  padding: 18px 18px 16px;
  border-radius: 20px;
  border: 1px solid rgba(210, 195, 165, 0.8);
  background: rgba(255, 250, 241, 0.92);
  cursor: pointer;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.steps__list li:hover {
  transform: translateY(-2px);
  border-color: rgba(189, 93, 56, 0.48);
}

.steps__list li.is-active {
  border-color: rgba(189, 93, 56, 0.7);
  box-shadow: 0 14px 32px rgba(189, 93, 56, 0.12);
}

.steps__list li strong {
  display: block;
  margin-bottom: 6px;
  font-size: 1rem;
}

.steps__number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 34px;
  height: 34px;
  margin-bottom: 12px;
  padding: 0 10px;
  border-radius: 999px;
  background: rgba(42, 111, 151, 0.1);
  color: var(--sky);
  font-weight: 800;
  font-size: 0.9rem;
}

.steps__list li p {
  color: var(--ink-500);
}

@media (max-width: 960px) {
  .viewer,
  .steps__list,
  .steps__header {
    grid-template-columns: 1fr;
  }

  .steps__header {
    display: grid;
  }
}

@media (max-width: 760px) {
  .page-shell {
    width: min(100% - 20px, 1200px);
    padding-top: 10px;
    padding-bottom: 22px;
  }

  .hero,
  .viewer,
  .steps {
    border-radius: 22px;
    padding: 18px;
  }

  .controls,
  .hero__actions {
    flex-direction: column;
    align-items: stretch;
  }

  .hero__title {
    max-width: 16ch;
    font-size: clamp(1.8rem, 8vw, 2.7rem);
  }

  .hero__lead {
    max-width: none;
    font-size: 0.98rem;
    line-height: 1.58;
  }

  .hero__actions {
    margin-top: 20px;
    gap: 10px;
  }

  .hero__chips {
    gap: 8px;
    margin-top: 14px;
  }

  .hero__chips li {
    font-size: 0.82rem;
    padding: 7px 10px;
  }

  .viewer {
    grid-template-columns: 1fr;
    grid-template-areas:
      "board"
      "controls"
      "panel";
    gap: 18px;
  }

  .viewer__board {
    padding: 14px;
  }

  .board-header {
    gap: 10px;
    margin-bottom: 12px;
  }

  .board {
    aspect-ratio: 1 / 1;
  }

  .step-card {
    padding: 18px;
  }

  .viewer__panel {
    gap: 12px;
  }

  .step-card__meta {
    margin-bottom: 12px;
  }

  .steps {
    padding: 20px 18px;
  }

  .steps__header {
    gap: 10px;
    margin-bottom: 14px;
  }

  .steps__header p {
    font-size: 0.95rem;
    line-height: 1.55;
  }

  .steps__list {
    gap: 10px;
  }

  .steps__list li {
    padding: 16px 16px 14px;
    border-radius: 18px;
  }

  .steps__number {
    min-width: 30px;
    height: 30px;
    margin-bottom: 10px;
    font-size: 0.82rem;
  }
}

@media (max-width: 520px) {
  .hero {
    padding: 16px;
  }

  .step-card h2 {
    font-size: 1.36rem;
  }

  .viewer {
    gap: 14px;
  }

  .viewer__board,
  .step-card {
    border-radius: 20px;
  }

  .viewer__board {
    padding: 12px;
  }

  .board-header {
    align-items: stretch;
    flex-direction: column;
  }

  .board-header__step {
    min-width: 0;
    font-size: 0.94rem;
  }

  .progress {
    width: 100%;
  }

  .ghost-button,
  .text-link,
  .nav-button {
    width: 100%;
    justify-content: center;
  }

  .viewer__controls {
    gap: 10px;
  }

  .text-link {
    min-height: 44px;
    padding: 10px 14px;
  }

  .step-card {
    padding: 16px;
  }

  .step-card__hint {
    margin-top: 14px;
    padding: 12px 14px;
    min-height: 0;
    font-size: 0.94rem;
  }

  .keyboard-tip {
    font-size: 0.9rem;
    line-height: 1.5;
  }

  .steps {
    padding: 18px 16px;
  }

  .steps__header h2 {
    font-size: 1.6rem;
  }

  .steps__list li strong {
    font-size: 0.98rem;
  }

  .steps__list li p {
    font-size: 0.92rem;
    line-height: 1.52;
  }
}