:root {
  --paper: #F5F0FF;
  --paper-raised: #FFFFFF;
  --ink: #1A1030;
  --ink-soft: #4A3870;
  --muted: #7B6A9A;
  --line: #D8CFF0;
  --accent: #5B3E8C;
  --accent-soft: #EDE8FA;
  --warm: #C4502A;
  --warm-soft: #FDF0EB;
  --radius: 12px;
}

*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }

body {
  background: var(--paper);
  color: var(--ink);
  font-family: 'Inter', system-ui, sans-serif;
  -webkit-font-smoothing: antialiased;
  line-height: 1.6;
}

.mono { font-family: 'JetBrains Mono', 'Fira Mono', monospace; }

.page {
  max-width: 680px;
  margin: 0 auto;
  padding: 52px 20px 80px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .13em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 5px 11px;
  border-radius: 5px;
  margin-bottom: 18px;
}

h1 {
  font-size: clamp(26px, 4.2vw, 38px);
  line-height: 1.12;
  letter-spacing: -.02em;
  margin: 0 0 14px;
}

.sub {
  color: var(--ink-soft);
  font-size: 16px;
  max-width: 50ch;
  margin: 0 0 36px;
}

/* Вкладки категорий */
.cat-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 28px;
}

.cat-btn {
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 14px;
  font-weight: 500;
  padding: 9px 18px;
  border-radius: 999px;
  border: 1.5px solid var(--line);
  background: var(--paper-raised);
  color: var(--ink-soft);
  cursor: pointer;
  transition: all .15s;
}

.cat-btn:hover { border-color: var(--accent); color: var(--accent); }
.cat-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* Панели */
.cat-panel { display: none; }
.cat-panel.active { display: block; }

/* Направление конвертации */
.direction-wrap {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.dir-btn {
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 13px;
  font-weight: 500;
  padding: 7px 14px;
  border-radius: 8px;
  border: 1.5px solid var(--line);
  background: var(--paper);
  color: var(--ink-soft);
  cursor: pointer;
  transition: all .15s;
}

.dir-btn.active {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
}

/* Блок ввода */
.input-wrap {
  background: var(--paper-raised);
  border: 1.5px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 20px;
}

.input-label {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
  display: block;
  margin-bottom: 10px;
}

.size-select {
  width: 100%;
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 17px;
  padding: 12px 14px;
  border-radius: 8px;
  border: 1.5px solid var(--line);
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
  outline: none;
  transition: border-color .15s;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%237B6A9A' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 40px;
}

.size-select:focus { border-color: var(--accent); }

/* Результат */
.result-block {
  background: var(--paper-raised);
  border: 1.5px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  opacity: 0;
  transform: translateY(6px);
  transition: opacity .25s ease, transform .25s ease;
  pointer-events: none;
}

.result-block.show {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.result-header {
  padding: 12px 18px;
  background: var(--accent-soft);
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.result-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--accent);
}

/* Сетка результатов */
.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
  gap: 0;
}

.result-cell {
  padding: 16px 18px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.result-cell:last-child { border-right: none; }

.cell-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 6px;
}

.cell-value {
  font-family: 'JetBrains Mono', 'Fira Mono', monospace;
  font-size: 22px;
  font-weight: 700;
  color: var(--ink);
}

.cell-sub {
  font-size: 12px;
  color: var(--muted);
  margin-top: 4px;
}

/* Заметка */
.size-note {
  font-size: 12.5px;
  color: var(--muted);
  margin-top: 12px;
  padding: 10px 14px;
  background: var(--warm-soft);
  border-left: 3px solid var(--warm);
  border-radius: 0 6px 6px 0;
}

/* Как работает */
.how {
  margin-top: 52px;
  padding-top: 32px;
  border-top: 1px solid var(--line);
}

.how-title {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 20px;
}

.how-list {
  list-style: none;
  margin: 0; padding: 0;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.how-list li {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  font-size: 15px;
  color: var(--ink-soft);
}

.how-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 12px;
  color: var(--accent);
  background: var(--accent-soft);
  width: 26px; height: 26px;
  flex-shrink: 0;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
}

.doc-links {
  margin-top: 36px;
  font-size: 13px;
  color: var(--muted);
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  align-items: center;
}

.doc-links a {
  color: var(--ink-soft);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  transition: color .15s, border-color .15s;
}

.doc-links a:hover { color: var(--accent); border-color: var(--accent); }

.disclaimer {
  margin-top: 32px;
  font-size: 12.5px;
  color: var(--muted);
  border-top: 1px solid var(--line);
  padding-top: 16px;
}

@media (max-width: 480px) {
  .page { padding: 32px 16px 60px; }
  .result-grid { grid-template-columns: 1fr 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  .result-block { transition: none !important; }
}