.difficulty-page {
  min-height: 100vh;
  padding: 32px 20px 64px;
  background:
    radial-gradient(circle at 12% 8%, rgba(var(--accent-rgb), 0.1), transparent 28rem),
    var(--bg);
}

.difficulty-shell {
  width: min(1180px, 100%);
  margin: 0 auto;
}

.difficulty-hero {
  max-width: 820px;
  padding: 44px 0 32px;
}

.difficulty-hero h1 {
  max-width: 760px;
  margin: 6px 0 16px;
  font-size: clamp(2.25rem, 6vw, 4.6rem);
  line-height: 0.98;
  letter-spacing: -0.055em;
}

.difficulty-lead {
  max-width: 720px;
  margin: 0;
  color: var(--text-secondary);
  font-size: clamp(1rem, 2vw, 1.15rem);
  line-height: 1.72;
}

.difficulty-summary {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 28px;
}

.difficulty-summary div {
  display: flex;
  min-height: 90px;
  flex-direction: column;
  justify-content: center;
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: color-mix(in srgb, var(--panel) 92%, transparent);
}

.difficulty-summary strong {
  font: 700 1.35rem/1.2 var(--font-display);
}

.difficulty-summary span {
  margin-top: 4px;
  color: var(--text-secondary);
  font-size: var(--text-sm);
}

.difficulty-card,
.difficulty-method {
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--panel);
  box-shadow: var(--shadow-2);
}

.difficulty-method > summary {
  grid-column: 1 / -1;
  cursor: pointer;
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
}

.difficulty-method[open] > summary {
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--border);
}

.difficulty-card {
  padding: clamp(18px, 4vw, 34px);
}

.difficulty-section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 20px;
}

.difficulty-section-heading h2,
.difficulty-method h2 {
  margin: 2px 0 0;
  font-size: clamp(1.5rem, 3vw, 2.35rem);
  letter-spacing: -0.035em;
}

.difficulty-section-heading > p {
  margin: 0 0 5px;
  color: var(--text-secondary);
  font-size: var(--text-sm);
  white-space: nowrap;
}

.difficulty-controls {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 12px;
  margin-top: 24px;
}

.difficulty-field {
  display: grid;
  gap: 7px;
  color: var(--text-secondary);
  font-size: var(--text-sm);
  font-weight: 650;
}

.difficulty-field input,
.difficulty-field select {
  width: 100%;
  min-height: 46px;
  padding: 0 13px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--input-bg);
  color: var(--text);
  font: inherit;
  font-weight: 500;
}

.difficulty-field input:focus,
.difficulty-field select:focus {
  border-color: var(--accent);
  outline: 3px solid var(--accent-soft);
}

.difficulty-toggles {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
  margin: 14px 0 24px;
}

.difficulty-toggles label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  background: var(--panel-2);
  color: var(--text-secondary);
  cursor: pointer;
  font-size: var(--text-sm);
}

.difficulty-toggles input {
  accent-color: var(--accent);
}

.difficulty-chart {
  display: grid;
  min-height: 150px;
  grid-template-columns: repeat(20, minmax(4px, 1fr));
  align-items: end;
  gap: 4px;
  padding: 18px 16px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
}

.difficulty-chart__bar {
  min-height: 4px;
  border-radius: 4px 4px 1px 1px;
  background: linear-gradient(180deg, var(--accent), color-mix(in srgb, var(--accent) 45%, var(--green)));
  opacity: 0.86;
}

.difficulty-chart__empty {
  grid-column: 1 / -1;
  place-self: center;
  color: var(--text-secondary);
  font-size: var(--text-sm);
}

.difficulty-table-wrap {
  margin-top: 18px;
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}

.difficulty-table {
  width: 100%;
  min-width: 1020px;
  border-collapse: collapse;
}

.difficulty-table th,
.difficulty-table td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  vertical-align: middle;
}

.difficulty-table th {
  background: var(--panel-2);
  color: var(--text-secondary);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

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

.difficulty-table tbody tr:hover {
  background: var(--bg-hover);
}

.difficulty-table td:first-child a,
.difficulty-table td:nth-child(2) strong {
  display: block;
  color: var(--text);
  font: 700 1rem/1.2 var(--font-display);
  text-decoration: none;
}

.difficulty-table td span {
  display: block;
  margin-top: 3px;
  color: var(--text-secondary);
  font-size: 0.75rem;
}

.difficulty-table .difficulty-why {
  width: 25%;
  min-width: 230px;
  color: var(--text-secondary);
  font-size: 0.78rem;
  line-height: 1.45;
}

.difficulty-pagination {
  display: flex;
  justify-content: center;
  gap: 6px;
  margin-top: 18px;
}

.difficulty-pagination button {
  min-width: 38px;
  min-height: 38px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--panel);
  color: var(--text);
  cursor: pointer;
}

.difficulty-pagination button[aria-current='page'] {
  border-color: var(--accent);
  background: var(--accent);
  color: var(--on-accent);
}

.difficulty-method {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: clamp(24px, 5vw, 58px);
  margin-top: 24px;
  padding: clamp(24px, 5vw, 48px);
}

.difficulty-method p {
  color: var(--text-secondary);
  line-height: 1.7;
}

.difficulty-formula {
  align-self: start;
  padding: 20px;
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
  background: var(--panel-2);
}

.difficulty-formula h3 {
  margin: 0 0 12px;
}

.difficulty-formula code {
  display: block;
  overflow-wrap: anywhere;
  color: var(--text);
  font-size: 0.82rem;
  line-height: 1.65;
}

.difficulty-shell > .related-tools {
  margin-top: 24px;
}

@media (max-width: 820px) {
  .difficulty-page {
    padding: 20px 12px 48px;
  }

  .difficulty-summary,
  .difficulty-controls,
  .difficulty-method {
    grid-template-columns: 1fr 1fr;
  }

  .difficulty-field--search,
  .difficulty-method > * {
    grid-column: 1 / -1;
  }
}

@media (max-width: 540px) {
  .difficulty-hero {
    padding-top: 30px;
  }

  .difficulty-summary,
  .difficulty-controls {
    grid-template-columns: 1fr;
  }

  .difficulty-summary div {
    min-height: 76px;
  }

  .difficulty-section-heading {
    align-items: start;
    flex-direction: column;
  }

  .difficulty-chart {
    gap: 2px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .difficulty-page * {
    scroll-behavior: auto !important;
  }
}