.page-features .tier-hero {
  padding-top: calc(var(--section-y) + var(--space-2));
}

.page-features .tier-stage {
  display: grid;
  gap: var(--space-6);
  margin-top: var(--space-4);
}

.page-features .tier-intro {
  display: grid;
  gap: var(--space-2);
  align-content: end;
}

.page-features .tier-kicker {
  margin: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-ink-muted);
}

.page-features .tier-title {
  margin: 0;
  font-size: var(--text-display);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.page-features .tier-lede {
  margin: 0;
  max-width: 46ch;
  color: var(--color-ink-soft);
  font-size: var(--text-base);
  line-height: var(--leading-body);
}

.page-features .tier-bignum {
  margin: var(--space-2) 0 0;
  font-size: var(--text-figure);
  line-height: 1;
  letter-spacing: var(--tracking-heading);
  color: var(--color-primary);
}

/* ---- 刻度选择器 ---- */
.page-features .tier-scales {
  display: grid;
  gap: var(--space-2);
  align-content: center;
}

.page-features .tier-scale {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-2) var(--space-3);
  text-align: left;
  background: color-mix(in srgb, var(--color-surface-alt) 55%, transparent);
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-md);
  color: var(--color-ink-soft);
  cursor: pointer;
  transition: border-color 180ms ease, background 180ms ease, color 180ms ease;
}

.page-features .tier-num {
  font-size: var(--text-sm);
  color: var(--color-ink-muted);
}

.page-features .tier-who {
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  white-space: nowrap;
}

.page-features .tier-bar {
  display: block;
  height: 4px;
  border-radius: var(--radius-pill);
  background: linear-gradient(
    90deg,
    color-mix(in srgb, var(--color-primary) 85%, transparent),
    color-mix(in srgb, var(--color-accent) 30%, transparent)
  );
  box-shadow: 0 0 12px color-mix(in srgb, var(--color-primary) 42%, transparent);
}

.page-features .tier-scale:nth-child(1) .tier-bar { width: 30%; height: 3px; }
.page-features .tier-scale:nth-child(2) .tier-bar { width: 52%; height: 5px; }
.page-features .tier-scale:nth-child(3) .tier-bar { width: 74%; height: 7px; }
.page-features .tier-scale:nth-child(4) .tier-bar { width: 96%; height: 9px; }

.page-features .tier-scale[aria-selected="true"] {
  border-color: color-mix(in srgb, var(--color-primary) 78%, transparent);
  background: color-mix(in srgb, var(--color-primary) 18%, var(--color-surface-alt));
  color: var(--color-ink);
}

.page-features .tier-scale[aria-selected="true"] .tier-num {
  color: var(--color-accent);
}

.page-features .tier-scale[aria-selected="true"] .tier-who {
  color: var(--color-ink);
}

@media (hover: hover) {
  .page-features .tier-scale:hover {
    border-color: var(--color-focus);
  }
}

/* ---- 档位面板 ---- */
.page-features .tier-panels {
  display: grid;
  gap: var(--space-4);
}

.page-features .tier-panel {
  display: grid;
  gap: var(--space-3);
  padding: var(--space-3);
  border: var(--border-thin) solid color-mix(in srgb, var(--color-primary) 30%, transparent);
  border-radius: var(--radius-lg);
  background: linear-gradient(
    160deg,
    color-mix(in srgb, var(--color-surface-alt) 88%, transparent),
    color-mix(in srgb, var(--color-surface) 94%, transparent)
  );
}

.page-features .tier-panel-media {
  aspect-ratio: 4 / 3;
  overflow: hidden;
}

.page-features .tier-panel-media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-features .tier-panel-body {
  display: grid;
  gap: var(--space-2);
  align-content: start;
}

.page-features .tier-panel-title {
  margin: 0;
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.page-features .tier-panel-lede {
  margin: 0;
  color: var(--color-ink-soft);
  font-size: var(--text-base);
  line-height: var(--leading-body);
}

.page-features .tier-list {
  list-style: none;
  margin: 0;
  padding: 0 0 0 var(--space-3);
  display: grid;
  gap: var(--space-2);
  border-left: var(--border-thin) solid color-mix(in srgb, var(--color-accent) 40%, transparent);
}

.page-features .tier-list li {
  color: var(--color-ink);
  font-size: var(--text-base);
  line-height: 1.72;
}

.page-features .tier-gap {
  margin: 0;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  background: color-mix(in srgb, var(--color-surface-deep) 55%, transparent);
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  line-height: 1.7;
}

/* ---- 差异对照 ---- */
.page-features .diff-head {
  display: grid;
  gap: var(--space-2);
  max-width: 64ch;
}

.page-features .diff-title {
  margin: 0;
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

.page-features .diff-lede {
  margin: 0;
  color: var(--color-ink-soft);
  font-size: var(--text-base);
  line-height: var(--leading-body);
}

.page-features .diff-lede a,
.page-features .diff-note a {
  color: var(--color-ink);
  text-decoration: none;
  border-bottom: var(--border-thin) solid color-mix(in srgb, var(--color-accent) 60%, transparent);
}

.page-features .diff-scroll {
  margin-top: var(--space-4);
  overflow-x: auto;
  border: var(--border-thin) solid var(--color-line);
  border-radius: var(--radius-lg);
  background: color-mix(in srgb, var(--color-surface) 72%, transparent);
  -webkit-overflow-scrolling: touch;
}

.page-features .diff-table {
  width: 100%;
  min-width: 680px;
  border-collapse: collapse;
  font-size: var(--text-sm);
}

.page-features .diff-table th,
.page-features .diff-table td {
  padding: var(--space-3);
  text-align: left;
  vertical-align: top;
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-features .diff-table thead th {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  letter-spacing: -0.01em;
  color: var(--color-primary);
  border-bottom-color: color-mix(in srgb, var(--color-primary) 55%, transparent);
  white-space: nowrap;
}

.page-features .diff-table tbody th {
  font-family: var(--font-body);
  font-weight: var(--weight-body);
  color: var(--color-ink-muted);
  white-space: nowrap;
}

.page-features .diff-table tbody td {
  font-family: var(--font-mono);
  color: var(--color-ink);
  letter-spacing: -0.01em;
  line-height: 1.6;
}

.page-features .diff-table tbody tr:last-child th,
.page-features .diff-table tbody tr:last-child td {
  border-bottom: 0;
}

@media (hover: hover) and (min-width: 768px) {
  .page-features .diff-table tbody tr {
    transition: opacity 160ms ease;
  }

  .page-features .diff-table tbody:hover tr {
    opacity: 0.42;
  }

  .page-features .diff-table tbody tr:hover {
    opacity: 1;
  }

  .page-features .diff-table tbody tr:hover th,
  .page-features .diff-table tbody tr:hover td {
    background: color-mix(in srgb, var(--color-primary) 16%, transparent);
    color: var(--color-ink);
  }
}

.page-features .diff-note {
  margin: var(--space-4) 0 0;
  max-width: 71ch;
  color: var(--color-ink-soft);
  font-size: var(--text-sm);
  line-height: 1.75;
}

/* ---- 建议断点 ---- */
.page-features .advice-inner {
  display: grid;
  gap: var(--space-3);
  max-width: 74ch;
}

.page-features .advice-kicker {
  margin: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-contrast-accent);
}

.page-features .advice-title {
  margin: 0;
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-contrast-ink);
}

.page-features .advice-copy {
  margin: 0;
  color: color-mix(in srgb, var(--color-contrast-ink) 82%, transparent);
  font-size: var(--text-base);
  line-height: var(--leading-body);
}

.page-features .advice-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-2);
}

.page-features .advice-section .btn:not(.btn--primary) {
  color: var(--color-contrast-ink);
  border-color: color-mix(in srgb, var(--color-contrast-ink) 30%, transparent);
  background: transparent;
}

/* ---- 桌面布局 ---- */
@media (min-width: 768px) {
  .page-features .tier-panel {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    align-items: start;
    gap: var(--space-4);
    padding: var(--space-4);
  }

  .page-features .tier-panel-media {
    grid-column: 1 / 6;
  }

  .page-features .tier-panel-body {
    grid-column: 6 / 13;
  }
}

@media (min-width: 1024px) {
  .page-features .tier-stage {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    column-gap: var(--gutter);
    row-gap: var(--space-8);
    align-items: end;
  }

  .page-features .tier-intro {
    grid-column: 1 / 6;
  }

  .page-features .tier-scales {
    grid-column: 7 / 13;
  }

  .page-features .tier-panels {
    grid-column: 1 / 13;
  }
}