/* ══════════════════════════════════════════════════════════
   漢詩 — Responsive styles
   Desktop base styles are in app.css (unchanged).
   This file only adds overrides for smaller viewports.

   Breakpoints:
     md   ≤ 1024px  small laptop / large tablet landscape
     sm   ≤  900px  tablet landscape
     xs   ≤  680px  tablet portrait / large phone
     xxs  ≤  480px  phone
   ══════════════════════════════════════════════════════════ */


/* ═══════════════════════════════════════════════════════════
   HAMBURGER BUTTON  (hidden on desktop)
   ═══════════════════════════════════════════════════════════ */
.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
  flex-shrink: 0;
}
.nav-hamburger span {
  display: block;
  height: 2px;
  background: var(--ink2);
  border-radius: 2px;
  transition: transform .22s, opacity .18s;
}
/* animated to ✕ when open */
.nav-hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }


/* ═══════════════════════════════════════════════════════════
   SIDEBAR FILTER TOGGLE  (visible only on mobile)
   ═══════════════════════════════════════════════════════════ */
.sidebar-toggle-btn {
  display: none;
}


/* ══════════════════════════════════════════════════════════
   md  ≤ 1024px
   ══════════════════════════════════════════════════════════ */
@media (max-width: 1024px) {
  /* Slightly tighten horizontal rhythm */
  .nav-inner           { padding: 0 1.5rem; }
  .home-hero           { padding: 3.5rem 1.5rem 2.5rem; gap: 2.5rem; }
  .qa-section          { padding: 0 1.5rem 3.5rem; }
  .two-col             { padding: 1.8rem 1.5rem; gap: 2rem; }
  .page-band           { padding: 1.1rem 1.5rem; }
  .compare-wrap        { padding: 2rem 1.5rem; }
  .adv-wrap            { padding: 2rem 2rem 2rem 1.5rem; }
  .insights-wrap       { padding: 1.8rem 1.5rem; }
  .more-wrap           { padding: 2.5rem 1.5rem; }
}


/* ══════════════════════════════════════════════════════════
   sm  ≤ 900px
   ══════════════════════════════════════════════════════════ */
@media (max-width: 900px) {

  /* ── Nav: show hamburger, hide desktop nav ── */
  .nav-hamburger { display: flex; }

  nav {
    display: none;          /* hidden until toggled */
    position: fixed;
    top: 58px;
    left: 0;
    right: 0;
    background: var(--paper);
    border-bottom: 1px solid var(--rule);
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: .4rem 0;
    box-shadow: 0 6px 24px rgba(26,23,20,.12);
    z-index: 199;
  }
  nav.open { display: flex; }

  nav a {
    padding: .78rem 1.5rem;
    font-size: .82rem;
    border-bottom: 1px solid var(--paper3);
    border-bottom-width: 1px !important;  /* override desktop active state */
    letter-spacing: .08em;
  }
  nav a:last-child { border-bottom: none; }
  nav a.active { color: var(--red); background: var(--paper2); border-bottom-color: var(--paper3) !important; }

  /* Compare dropdown becomes flat links in nav stack */
  .nav-compare-wrap { position: static; display: block; }
  .nav-compare-wrap > a {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--paper3);
  }
  .compare-dropdown {
    display: block !important;   /* always visible in mobile stack */
    position: static;
    box-shadow: none;
    border: none;
    padding: 0;
    background: var(--paper2);
  }
  .compare-dropdown a {
    padding: .65rem 2rem;
    font-size: .78rem;
    border-bottom: 1px solid var(--paper3) !important;
  }
  .compare-dropdown a:last-child { border-bottom: none !important; }

  /* Backdrop overlay when nav is open */
  body.nav-open::before {
    content: '';
    position: fixed;
    inset: 58px 0 0;
    background: rgba(26,23,20,.25);
    z-index: 198;
  }

  /* ── Home hero: stack columns ── */
  .home-hero {
    grid-template-columns: 1fr;
    gap: 2rem;
    padding: 3rem 1.5rem 2rem;
  }
  .home-hero h1 { font-size: 2.1rem; }

  /* ── QA grid: 2 columns ── */
  .qa-grid { grid-template-columns: repeat(2, 1fr); }

  /* ── Browse: sidebar collapses, toggle button appears ── */
  .sidebar-toggle-btn {
    display: flex;
    align-items: center;
    gap: .55rem;
    font-family: var(--sans);
    font-size: .82rem;
    letter-spacing: .07em;
    text-transform: uppercase;
    padding: .5rem .9rem;
    border: 1px solid var(--rule);
    background: var(--paper);
    color: var(--ink2);
    cursor: pointer;
    transition: all .15s;
    margin-bottom: 1rem;
    /* span full grid width so it sits above sidebar+main */
    grid-column: 1 / -1;
    align-self: start;
    width: fit-content;
  }
  .sidebar-toggle-btn:hover { border-color: var(--red); color: var(--red); }
  .sidebar-toggle-btn .stb-icon {
    font-size: .9rem;
    transition: transform .2s;
    display: inline-block;
  }
  .sidebar-toggle-btn.open .stb-icon { transform: rotate(180deg); }

  .two-col {
    grid-template-columns: 1fr;
    gap: 0;
    padding: 1.5rem 1.2rem;
    /* Prevent the grid container itself from overflowing */
    overflow: hidden;
  }
  /* Grid blowout fix: all direct children must not exceed the column */
  .two-col > * { min-width: 0; }

  .sidebar {
    display: none;          /* hidden by default on mobile */
    width: 100%;
    box-sizing: border-box;
    overflow-x: hidden;     /* clip any inner content that overflows */
    border: 1px solid var(--rule);
    background: var(--paper2);
    padding: 1rem 1.1rem;
    margin-bottom: 1.4rem;
  }
  .sidebar.open { display: block; }

  /* ── Filter list: long titles shouldn't bust out ── */
  .filter-list li {
    overflow: hidden;
    min-width: 0;
  }
  .filter-list li .fc { flex-shrink: 0; }

  /* ── AZ bar: guarantee wrap, no horizontal bleed ── */
  .az-bar { flex-wrap: wrap; max-width: 100%; overflow: hidden; }

  /* ── Search input inside sidebar ── */
  .sidebar .search-wrap { width: 100%; }
  .sidebar .search-input { box-sizing: border-box; width: 100%; }

  /* ── Year slider: contain within sidebar ── */
  .yr-track-wrap { touch-action: none; }
  .yr-inputs { flex-wrap: wrap; gap: .3rem; }
  .yr-num { min-width: 0; }

  /* ── Table scroll wrapper ──
     Must be display:block with explicit width so the table can
     resolve percentage widths correctly and not break the grid.  */
  .results-table-wrap {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    display: block;
    width: 100%;
  }
  .results-table { min-width: 640px; }

  /* ── Sticky thead fix ──
     overflow-x: auto creates an overflow formatting context that
     breaks position:sticky's vertical scroll reference.
     Disable sticky on mobile — the table scrolls naturally instead. ──*/
  .results-table thead th {
    position: relative;
    top: auto;
    z-index: auto;
    background: var(--paper3);  /* visual distinction without sticky */
  }

  /* ── Insights: 2-col top stat → 2×2 grid ── */
  .insights-top {
    grid-template-columns: repeat(2, 1fr);
  }
  .ins-stat:nth-child(2) { border-right: none; }
  .ins-stat:nth-child(3) { border-top: 1px solid var(--rule); }
  .ins-stat:nth-child(4) { border-top: 1px solid var(--rule); }

  /* Tighten label line-height so 2-line labels don't feel double-spaced */
  .ins-l { line-height: 1.3; }

  /* ── Insights charts & rank cols: 1 col ── */
  .insights-cols { grid-template-columns: 1fr; }

  /* Translator rank list: 1 col */
  #rank-translators { grid-template-columns: 1fr !important; }

  /* ── Compare selectors: vertical stack ── */
  .compare-selectors {
    grid-template-columns: 1fr;
    gap: 1.2rem;
  }
  .compare-vs { display: none; }  /* hide "vs" dividers; text is obvious from labels */

  /* ── Advanced search rows ──
     條件列在窄螢幕改直式：Field 與移除鈕同一行，Operator、Value 各自一行。
     子元素順序為 Field / Operator / Value / 移除鈕（見 advanced.js advRenderCond）。 */
  .adv-row {
    grid-template-columns: minmax(0, 1fr) 24px;
    grid-template-areas:
      "field x"
      "op    op"
      "val   val";
    gap: .45rem .5rem;
  }
  .adv-row > *:nth-child(1) { grid-area: field; }
  .adv-row > *:nth-child(2) { grid-area: op; }
  .adv-row > *:nth-child(3) { grid-area: val; }
  .adv-row > *:nth-child(4) { grid-area: x; justify-self: end; }

  /* 巢狀群組在窄螢幕縮排收窄，避免第 2 層被擠到沒有寬度 */
  .adv-card  { padding: 1.1rem 1rem; }
  .adv-group { padding: .85rem .8rem; }

  /* (table scroll rules moved up into the grid-fix block above) */

  /* ── Page band ── */
  .page-band { padding: 1rem 1.2rem; }
  .page-band h2 { font-size: 1.3rem; }

  /* ── Footer ── */
  .site-footer { padding: .75rem 1rem; }
}


/* ══════════════════════════════════════════════════════════
   xs  ≤ 680px
   ══════════════════════════════════════════════════════════ */
@media (max-width: 680px) {

  body { font-size: 16px; padding-bottom: 2.5rem; }

  /* ── Nav ── */
  .nav-inner { padding: 0 1rem; height: 52px; }
  nav { top: 52px; }
  /* Backdrop inset must match the 52px nav height at this breakpoint */
  body.nav-open::before { inset: 52px 0 0; }
  /* sticky is already disabled at ≤900px (position:relative); keep top:auto */
  .results-table thead th { top: auto; }

  /* ── Logo text: hide on very narrow header ── */
  .logo-en { display: none; }
  .logo-img { height: 38px; }

  /* ── Home ── */
  .home-hero { padding: 2.2rem 1rem 1.5rem; gap: 1.5rem; }
  .home-hero h1 { font-size: 1.8rem; }
  .home-desc { font-size: .92rem; max-width: 100%; }

  .stats-grid { margin-bottom: 1.2rem; }
  .stat-n { font-size: 1.5rem; }

  .qa-section { padding: 0 1rem 3rem; }
  .qa-head { font-size: .68rem; padding-top: 1.4rem; margin-bottom: .7rem; }
  .qa-grid { grid-template-columns: 1fr 1fr; gap: .4rem; }
  .qa-card { padding: .7rem .75rem; }
  .qa-title { font-size: .77rem; }
  .qa-hint { font-size: .7rem; }

  /* ── Browse ── */
  .two-col { padding: 1.1rem 1rem; }
  .results-bar { flex-direction: column; align-items: flex-start; gap: .4rem; }

  /* Chips */
  .chips { gap: .25rem; }
  .chip { font-size: .74rem; padding: .18rem .5rem; }

  /* Pagination tighter */
  .pg-btn { padding: .28rem .5rem; font-size: .78rem; }

  /* ── Advanced ── */
  .adv-wrap { padding: 1.4rem 1rem; }

  /* ── Compare ── */
  .compare-wrap { padding: 1.5rem 1rem; }
  .compare-note { font-size: .77rem; }

  /* ── Insights ── */
  .insights-wrap { padding: 1.4rem 1rem; }
  .ins-n { font-size: 1.35rem; }
  .ins-stat { padding: .85rem 1rem; }

  .rank-card { padding: 1rem 1.1rem; }
  .rank-name { font-size: .88rem; }
  .rank-bar-wrap { width: 56px; }

  .chart-canvas-wrap  { height: 200px; overflow: hidden; }
  .chart-canvas-wide  { height: 170px; overflow: hidden; }

  /* Chart.js canvases must not exceed their container */
  .chart-canvas-wrap canvas,
  .chart-canvas-wide canvas { max-width: 100%; }

  /* rank-card in a single-col grid must not blow out */
  .rank-card { min-width: 0; overflow: hidden; }

  /* ── More ── */
  .more-wrap { padding: 2rem 1rem; }
  .more-body { font-size: 1rem; }

  /* ── Page band ── */
  .page-band { padding: .9rem 1rem; }

  /* ── Modal ── */
  .modal { padding: 1.4rem; }
}


/* ══════════════════════════════════════════════════════════
   xxs  ≤ 480px
   ══════════════════════════════════════════════════════════ */
@media (max-width: 480px) {

  /* ── Home hero ── */
  .home-hero { padding: 1.8rem .9rem 1.2rem; }
  .home-hero h1 { font-size: 1.6rem; line-height: 1.28; }

  /* QA: single column on very small phones */
  .qa-grid { grid-template-columns: 1fr; }

  /* ── Stats grid: keep 2×2 but smaller cells ── */
  .stat-cell { padding: .75rem .65rem; }
  .stat-n { font-size: 1.35rem; }
  .stat-l { font-size: .72rem; }

  /* ── Browse ── */
  .two-col { padding: .9rem .9rem; }

  /* Page size selector + count stacked */
  .results-bar > div:last-child { align-self: flex-start; }

  /* ── Advanced ── */
  .adv-wrap  { padding: 1rem .9rem; }
  .adv-card  { padding: .9rem .75rem; }
  .adv-group { padding: .75rem .6rem; }
  .adv-preview { font-size: .78rem; padding: .7rem .8rem; }

  /* ── Compare ── */
  .compare-wrap { padding: 1.2rem .9rem; }

  /* ── Insights ── */
  .insights-wrap { padding: 1.1rem .9rem; }
  .insights-top { grid-template-columns: 1fr 1fr; } /* keep 2×2 */

  /* ── More ── */
  .more-wrap { padding: 1.5rem .9rem; }

  /* ── QA popup ── */
  .qa-popup { padding: 1.3rem 1rem; }

  /* ── Page band ── */
  .page-band { padding: .75rem .9rem; }
  .page-band h2 { font-size: 1.2rem; }
}


/* ══════════════════════════════════════════════════════════
   UTILITY: safe-area insets for notched phones
   ══════════════════════════════════════════════════════════ */
@supports (padding: env(safe-area-inset-left)) {
  .nav-inner,
  .home-hero,
  .qa-section,
  .two-col,
  .page-band-inner,
  .compare-wrap,
  .adv-wrap,
  .insights-wrap,
  .more-wrap {
    padding-left:  max(var(--side-pad, .9rem), env(safe-area-inset-left));
    padding-right: max(var(--side-pad, .9rem), env(safe-area-inset-right));
  }
}