@media (max-width: 900px) {
  .sidebar { display: none; }

  .mobile-header {
    position: sticky;
    top: 0;
    z-index: 50;
    display: flex;
    min-height: 62px;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--line);
    background: rgba(13,13,12,.94);
    padding: 9px clamp(14px, 3vw, 24px);
  }

  .mobile-header .brand {
    flex-direction: row;
    gap: 9px;
    text-align: left;
  }
  .mobile-header .brand-mark { width: 34px; height: 34px; }
  .mobile-header .brand strong { font-size: 10px; letter-spacing: .13em; }

  .mobile-header nav {
    position: fixed;
    right: 0;
    bottom: 0;
    left: 0;
    z-index: 60;
    display: grid;
    grid-template-columns: repeat(6, minmax(0, 1fr));
    min-height: 70px;
    border-top: 1px solid #37362f;
    background: rgba(16,16,15,.97);
    padding: 5px 6px max(5px, env(safe-area-inset-bottom));
    box-shadow: 0 -12px 32px rgba(0,0,0,.38);
    backdrop-filter: blur(18px);
  }

  .mobile-header nav a {
    position: relative;
    display: flex;
    min-width: 0;
    min-height: 56px;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    color: #88867f;
    padding: 4px 2px 3px;
    font-size: 9px;
    font-weight: 650;
    line-height: 1;
    text-align: center;
  }
  .mobile-header nav a::before {
    position: absolute;
    top: -5px;
    left: 22%;
    width: 56%;
    height: 2px;
    background: transparent;
    content: '';
  }
  .mobile-header nav a.active { color: var(--text); }
  .mobile-header nav a.active::before { background: var(--gold); }
  .mobile-header nav img {
    width: 23px;
    height: 23px;
    object-fit: contain;
    opacity: .62;
  }
  .mobile-header nav a.active img { opacity: 1; }
  .mobile-header nav span {
    display: block;
    overflow: hidden;
    width: 100%;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .language-switcher-mobile {
    display: block;
    flex: 0 0 auto;
    margin: 0;
  }
  .language-switcher-mobile .language-trigger {
    width: auto;
    min-height: 38px;
    padding: 7px 9px;
    gap: 7px;
  }
  .language-switcher-mobile .language-menu {
    right: 0;
    bottom: auto;
    left: auto;
    top: calc(100% + 7px);
    width: 160px;
  }

  .content {
    width: 100%;
    max-width: none;
    margin-left: 0;
    padding: 34px clamp(18px, 4vw, 34px) calc(104px + env(safe-area-inset-bottom));
  }

  .page-head { align-items: flex-start; }
  h1 { font-size: clamp(34px, 6vw, 46px); }
  .catalog-description { max-width: 70ch; }

  .filters,
  .filters.champion-filters,
  .filters.skinline-filters,
  .chinese-chroma-toolbar {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .filters > .catalog-filter:not(:first-child),
  .chinese-chroma-toolbar > .catalog-filter:not(:first-child) {
    width: 100%;
    max-width: none;
  }

  .skin-grid, .chinese-chroma-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px 13px;
  }
  .champion-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px 13px;
  }

  .collection-summary { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .collection-rarity-summary {
    grid-column: 1 / -1;
    border-top: 1px solid var(--line);
    border-left: 0;
  }

  .line-grid { gap: 16px; }
  .line-card-content { min-height: 0; padding: 30px 28px; }
  .line-card h2 { font-size: clamp(31px, 6vw, 44px); }

  .detail-hero { display: block; min-height: 0; }
  .detail-splash {
    width: 100%;
    min-height: 0;
    aspect-ratio: 16 / 9;
  }
  .detail-panel {
    border-top: 1px solid var(--line);
    border-left: 0;
    padding: 32px 28px;
  }
  .detail-panel h1 { max-width: none; }

  .champion-detail-hero { display: block; min-height: 0; }
  .champion-detail-image {
    width: min(100%, 520px);
    margin-inline: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
  .champion-detail-panel { padding: 32px 28px; }

  .chroma-layout.chroma-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 9px;
  }
  .chroma-feature {
    grid-column: 1 / -1;
    grid-row: auto;
    grid-template-columns: 1fr;
  }
  .chroma-preview {
    width: 100%;
    min-height: 0;
    aspect-ratio: 16 / 9;
    border-right: 0;
    border-bottom: 1px solid var(--line);
  }
  .chroma-info { padding: 26px; }
  .generated-chroma-card { padding: 9px; }

  .chinese-chroma-detail-layout { grid-template-columns: 1fr; }
  .champion-chroma-selector-slot {
    min-height: clamp(360px, 60vh, 520px);
    aspect-ratio: auto;
  }
}

@media (max-width: 700px) {
  .collection-rarity-summary {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}