/* Homepage UI: light theme, automatic dark via prefers-color-scheme. */

:root {
  --bg-1: #eef2ff;
  --bg-2: #f7f9ff;
  --bg-3: #e2e8f8;
  --fg: #1f2937;
  --muted: #64748b;
  --card: rgba(255, 255, 255, 0.85);
  --field-bg: rgba(255, 255, 255, 0.85);
  --border: #cbd5e1;
  --accent: #4f6df5;
  --accent-fg: #ffffff;
  --danger: #dc2626;
  /* Grid metrics — layout() in app.js writes these as resolved px on
     :root (dnd.js parses --tile-w/--tile-h); the values here are the
     desktop fallbacks before JS runs.
     Sizing formula (per spacing preset: frac = target share of the
     viewport width, gapShare = share of that target spent on column
     gaps, gapMin/gapMax = gap range, tileMax = tile width cap,
     rowMul = row-gap multiplier):
       availW = vw − 2·padX      availH = vh − 2·padY
       F      = min(availW, lerp(0.94 → frac) · vw)   target grid width
                (the share eases toward near-full width below 1024px)
       gapX   = clamp(gapMin, F·gapShare/(cols−1), gapMax)
       gapY   = gapX · rowMul
       tileW  = min(tileMax,
                    (F      − (cols−1)·gapX) / cols,  fill the target
                    (availW − (cols−1)·gapX) / cols,  never overflow
                    rowFit / 0.92 and icon+label fit) height bound
       tileH  = clamp(aspect·tileW, icon + label block, rowFit)
       rowFit = (availH − (rows−1)·gapY) / rows
       padX   = 64px while the side arrows overlay the grid (≥768px and
                more than one page), 12px otherwise; padY = 12px.
     Gaps shrink to gapMin before tiles give way, so the configured grid
     (rows 3–5 × cols 4–6) always fits the viewport. Icon, label, edit
     badge and link gap derive from --tile-w via clamp(). */
  --tile-w: 106px;
  --tile-h: 98px;
  --grid-gap-x: 32px;
  --grid-gap-y: 32px;
  --page-pad-x: 64px;
  --page-pad-y: 12px;
  --icon: clamp(36px, calc(var(--tile-w) * 0.62), 72px);
  --title-fs: clamp(12px, calc(var(--tile-w) * 0.125), 14px);
  --edit-sz: clamp(20px, calc(var(--tile-w) * 0.24), 26px);
  --radius: 14px;
  --shadow: 0 4px 16px rgba(30, 41, 59, 0.1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-1: #0b1220;
    --bg-2: #101a2e;
    --bg-3: #0f172a;
    --fg: #e2e8f0;
    --muted: #94a3b8;
    --card: rgba(30, 41, 59, 0.92);
    --field-bg: rgba(15, 23, 42, 0.6);
    --border: #3b4a63;
    --shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
  }
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  display: flex;
  flex-direction: column;
  font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto,
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--fg);
  background: linear-gradient(150deg, var(--bg-1), var(--bg-2) 45%, var(--bg-3));
  background-attachment: fixed;
  overflow-x: clip; /* belt & suspenders: nothing may scroll horizontally */
}

/* ---------- header ---------- */

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
}

.topbar-title {
  margin: 0;
  font-size: 20px;
  font-weight: 650;
  letter-spacing: 0.02em;
}

.topbar-actions {
  display: flex;
  gap: 8px;
}

/* ---------- buttons ---------- */

.btn {
  padding: 8px 14px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--fg);
  font-size: 14px;
  cursor: pointer;
  transition: border-color 0.15s, transform 0.05s;
}

.btn:hover {
  border-color: var(--accent);
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-fg);
}

.btn-danger {
  background: var(--danger);
  border-color: var(--danger);
  color: #fff;
}

.btn-icon {
  padding: 8px 11px;
}

/* ---------- app / paging ---------- */

#app {
  flex: 1;
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.viewport {
  flex: 1;
  position: relative;
  overflow: hidden;
  touch-action: pan-y pinch-zoom;
}

.track {
  display: flex;
  height: 100%;
  transition: transform 0.32s ease;
  will-change: transform;
}

.track.no-anim {
  transition: none;
}

.page {
  flex: 0 0 100%;
  display: grid;
  justify-content: center;
  align-content: center;
  /* --cols/--rows are set inline on each page by renderTrack(); the
     metrics vars come from :root via layout(). */
  --cols: 6;
  --rows: 4;
  grid-template-columns: repeat(var(--cols), var(--tile-w));
  grid-template-rows: repeat(var(--rows), var(--tile-h));
  gap: var(--grid-gap-y) var(--grid-gap-x);
  padding: var(--page-pad-y) var(--page-pad-x);
}

.empty {
  grid-column: 1 / -1;
  margin: 0;
  padding: 40px 0;
  color: var(--muted);
  font-size: 15px;
  text-align: center;
}

/* ---------- tiles ---------- */

.tile {
  position: relative;
  width: var(--tile-w);
  height: var(--tile-h);
  /* Touches starting on a tile never become a native pan, so the browser
     can't steal the long-press → drag gesture (pinch-zoom stays allowed).
     Selection/callout are off so a hold doesn't highlight the title. */
  touch-action: pinch-zoom;
  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
}

.tile-link {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: clamp(4px, calc(var(--tile-w) * 0.08), 10px);
  height: 100%;
  padding-top: 2px;
  text-decoration: none;
  color: var(--fg);
  border-radius: var(--radius);
}

.tile-link:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.tile-icon {
  width: var(--icon);
  height: var(--icon);
  border-radius: calc(var(--icon) * 0.28);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.tile-icon img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.avatar {
  width: var(--icon);
  height: var(--icon);
  border-radius: calc(var(--icon) * 0.28);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: calc(var(--icon) * 0.44);
  font-weight: 600;
  box-shadow: var(--shadow);
  user-select: none;
}

.tile-title {
  max-width: 100%;
  font-size: var(--title-fs);
  line-height: 1.3;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.tile-edit {
  position: absolute;
  top: calc(var(--edit-sz) * -0.29);
  right: calc(var(--edit-sz) * -0.29);
  z-index: 2;
  width: var(--edit-sz);
  height: var(--edit-sz);
  padding: 0;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--fg);
  font-size: calc(var(--edit-sz) * 0.54);
  line-height: 1;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s;
}

.tile:hover .tile-edit,
.tile:focus-within .tile-edit {
  opacity: 1;
}

/* Touch devices have no hover: keep the affordance faintly visible. */
@media (hover: none) {
  .tile-edit {
    opacity: 0.85;
  }
}

/* Freshly added tile: app.js tags it .tile-new for ~1.5s so the pulse
   draws the eye to where the bookmark landed. */
.tile-new .tile-link {
  outline: 3px solid transparent;
  outline-offset: 2px;
  animation: tile-new-pulse 0.75s ease-in-out 2;
}

@keyframes tile-new-pulse {
  50% {
    outline-color: var(--accent);
  }
}

/* ---------- drag & drop ---------- */

/* The dragged item's slot collapses to a dashed placeholder; it moves
   through the grid as the item is live-reordered. */
.tile.tile-source {
  border-radius: var(--radius);
  outline: 2px dashed var(--accent);
  outline-offset: -3px;
}

.tile.tile-source .tile-link,
.tile.tile-source .tile-edit {
  visibility: hidden;
}

/* Floating clone that follows the pointer (positioned inline in dnd.js
   by a rAF loop). Two invariants live here so they can't regress: it is
   pointer-events:none (hit-testing for drop targets must always see
   through it) and it never transitions — any transform animation would
   make the ghost trail the pointer. */
.drag-clone {
  pointer-events: none;
  transition: none !important;
  border-radius: var(--radius);
  background: var(--card);
  box-shadow: 0 14px 34px rgba(15, 23, 42, 0.3);
  cursor: grabbing;
}

body.dnd-active,
body.dnd-active * {
  cursor: grabbing !important;
}

/* While a drag dwells in an edge zone, a soft gradient marks the side
   that is about to flip pages (dnd.js toggles the body classes). */
.viewport::before,
.viewport::after {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  z-index: 4; /* above tiles, below the nav arrows (z-index 5) */
  width: max(56px, 8%); /* mirrors edgeZonePx() in dnd.js */
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
}

.viewport::before {
  left: 0;
  background: linear-gradient(to right, rgba(79, 109, 245, 0.18), transparent);
  background: linear-gradient(to right,
    color-mix(in srgb, var(--accent) 18%, transparent), transparent);
}

.viewport::after {
  right: 0;
  background: linear-gradient(to left, rgba(79, 109, 245, 0.18), transparent);
  background: linear-gradient(to left,
    color-mix(in srgb, var(--accent) 18%, transparent), transparent);
}

body.dnd-edge-left .viewport::before,
body.dnd-edge-right .viewport::after {
  opacity: 1;
}

/* ---------- arrows & dots ---------- */

/* The pager row sits below the viewport: ‹  • • •  ›. On narrow screens
   the arrows are ordinary flex items next to the dots; at ≥768px they
   become absolute overlays in the page side gutters (see media query).
   layout() reads back the computed position to decide how much gutter
   the grid must reserve — one source of truth, no mirrored breakpoint. */
.pager {
  display: flex;
  flex: none;
  align-items: center;
  justify-content: center;
  gap: 18px;
  padding: 12px 0 18px;
}

.nav-arrow {
  flex: 0 0 auto; /* disabled arrows stay invisible but keep dots centered */
  width: 44px;
  height: 44px;
  padding: 0;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--fg);
  font-size: 24px;
  line-height: 1;
  cursor: pointer;
  transition: opacity 0.2s;
}

.nav-arrow:disabled {
  opacity: 0;
  pointer-events: none;
}

@media (min-width: 768px) {
  .nav-arrow {
    position: absolute; /* overlays #app: .pager is not positioned */
    top: 50%;
    transform: translateY(-50%);
    z-index: 5;
  }

  .nav-prev {
    left: 14px;
  }

  .nav-next {
    right: 14px;
  }
}

.dots {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
}

.dot {
  width: 9px;
  height: 9px;
  padding: 0;
  border: none;
  border-radius: 50%;
  background: var(--muted);
  opacity: 0.35;
  cursor: pointer;
}

.dot.active {
  opacity: 1;
  background: var(--accent);
  transform: scale(1.25);
}

/* ---------- modals ---------- */

.modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  background: rgba(15, 23, 42, 0.45);
}

.modal-backdrop[hidden] {
  display: none;
}

.modal {
  width: min(92vw, 400px);
  padding: 22px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--card);
  box-shadow: 0 16px 48px rgba(15, 23, 42, 0.28);
  color: var(--fg);
}

.modal h2 {
  margin: 0 0 18px;
  font-size: 17px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 14px;
  font-size: 14px;
}

.field input,
.field select {
  padding: 9px 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--field-bg);
  color: var(--fg);
  font-size: 14px;
}

.field input:focus,
.field select:focus {
  outline: 2px solid var(--accent);
  outline-offset: -1px;
}

.field input[type="file"] {
  max-width: 100%;
  font-size: 13px;
}

.field-row {
  display: flex;
  gap: 12px;
}

.field-row .field {
  flex: 1;
}

.row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 8px;
}

.radio-row {
  font-size: 14px;
}

.radio-row label {
  display: flex;
  align-items: center;
  gap: 5px;
}

.modal-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 6px;
}

.modal-actions .spacer {
  flex: 1;
}

.modal-msg {
  margin: 8px 0 0;
  font-size: 13px;
  color: var(--muted);
}

.modal-msg.error {
  color: var(--danger);
}

/* ---------- toast ---------- */

.toast {
  position: fixed;
  left: 50%;
  bottom: 30px;
  z-index: 80;
  transform: translateX(-50%);
  max-width: 88vw;
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--fg);
  color: var(--bg-2);
  font-size: 14px;
  box-shadow: var(--shadow);
}

.toast[hidden] {
  display: none;
}

/* ---------- motion ---------- */

@media (prefers-reduced-motion: reduce) {
  .track {
    transition: none;
  }
  /* No pulse: a static accent ring marks the new tile for the same
     ~1.5s window (app.js removes .tile-new on a timer). */
  .tile-new .tile-link {
    animation: none;
    outline-color: var(--accent);
  }
}