/* ==========================================================================
 * styles.css — Digital Magazine Reader
 *   1. Theme tokens   2. Base   3. Reader stage & pages   4. Page turn
 *   5. Bars & controls   6. Thumbnails   7. Overlays   
 *   8. Responsive / motion
 * ========================================================================== */

/* ---------- 1. Theme tokens (dark is the default) ---------- */
:root {
  --bg: #15161a;
  --bg-grad: radial-gradient(120% 90% at 50% 40%, #23252d 0%, #15161a 60%, #0d0e11 100%);
  --surface: rgba(26, 28, 34, .82);
  --surface-solid: #1c1e24;
  --surface-2: rgba(255, 255, 255, .07);
  --text: #eceef2;
  --text-dim: #9aa0ad;
  --accent: #e9b44c;
  --accent-ink: #1b1405;
  --border: rgba(255, 255, 255, .1);
  --focus: #8ec1ff;
  --page-paper: #ffffff;
  --ph-a: #2a2d36;
  --ph-b: #363a46;
  --page-shadow: rgba(0, 0, 0, .55);
  --thumbs-w: 212px;
  --thumbs-h: 138px;
  --top-h: 56px;
  --bottom-h: 64px;
  color-scheme: dark;
}
:root[data-theme="light"] {
  --bg: #e6e2d9;
  --bg-grad: radial-gradient(120% 90% at 50% 40%, #f3f0e9 0%, #e6e2d9 60%, #d6d1c5 100%);
  --surface: rgba(252, 250, 246, .86);
  --surface-solid: #fbf9f4;
  --surface-2: rgba(0, 0, 0, .06);
  --text: #1d1f24;
  --text-dim: #5b606c;
  --accent: #a85c00;
  --accent-ink: #ffffff;
  --border: rgba(0, 0, 0, .13);
  --focus: #0b5fd6;
  --ph-a: #e2ded4;
  --ph-b: #efece4;
  --page-shadow: rgba(60, 45, 15, .42);
  color-scheme: light;
}

/* ---------- 2. Base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { font-size: clamp(15px, .45vw + 10px, 26px); -webkit-text-size-adjust: 100%; }
body {
  margin: 0; min-height: 100%;
  background: var(--bg); color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.4;
  -webkit-tap-highlight-color: transparent;
}
body.reader { height: 100%; overflow: hidden; overscroll-behavior: none; background: var(--bg-grad); }
button, input { font: inherit; color: inherit; }
button { cursor: pointer; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; border-radius: 6px; }
.sr-only {
  position: absolute !important; width: 1px; height: 1px; margin: -1px; padding: 0;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}
.skip-link {
  position: fixed; left: .5rem; top: -4rem; z-index: 100; padding: .5rem .9rem;
  background: var(--accent); color: var(--accent-ink); border-radius: .5rem; text-decoration: none; font-weight: 600;
}
.skip-link:focus { top: .5rem; }

/* ---------- 3. Reader stage & pages ---------- */
.stage {
  position: fixed; inset: 0; overflow: hidden; outline: none;
  touch-action: none; user-select: none; -webkit-user-select: none; -webkit-touch-callout: none;
}
.zoom-layer {
  position: absolute;
  left: var(--pad-l, 0); right: var(--pad-r, 0); top: var(--pad-t, 0); bottom: var(--pad-b, 0);
  display: flex; align-items: center; justify-content: center;
  transform-origin: 50% 50%;
}
.stage.zoomed { cursor: grab; }
.stage.panning { cursor: grabbing; }
.stage[data-zone="left"], .stage[data-zone="right"] { cursor: pointer; }

.book {
  position: relative; flex: none;
  width: var(--book-w, 0px); height: var(--book-h, 0px);
  perspective: calc(var(--pw, 400px) * 3.4);       /* depth of the 3D page turn */
}
.layers { position: absolute; inset: 0; }
.layer { position: absolute; inset: 0; }
.slot { position: absolute; top: 0; width: var(--pw); height: var(--ph); }
.slot-l { left: 0; }
.slot-r { left: var(--pw); }
.book.single .slot-r { left: 0; }
.book.single .slot-l { display: none; }

/* One magazine page */
.page {
  position: absolute; inset: 0; overflow: hidden;
  background: var(--page-paper);
}
.slot .page.side-l { box-shadow: -10px 16px 36px -8px var(--page-shadow); }
.slot .page.side-r { box-shadow: 10px 16px 36px -8px var(--page-shadow); }
.slot .page.side-s { box-shadow: 0 18px 46px -6px var(--page-shadow); }
/* Centre-spine / gutter shading, painted on each page so it travels with a turning leaf */
.page::after { content: ""; position: absolute; inset: 0; pointer-events: none; }
.page.side-r::after {
  background: linear-gradient(to right, rgba(0,0,0,.30) 0, rgba(0,0,0,.10) 2.5%, rgba(0,0,0,.02) 7%, transparent 12%);
}
.page.side-l::after {
  background: linear-gradient(to left, rgba(0,0,0,.30) 0, rgba(0,0,0,.10) 2.5%, rgba(0,0,0,.02) 7%, transparent 12%);
}
.page.blank { background: var(--page-paper); }
.page-img {
  position: absolute; inset: 0; width: 100%; height: 100%;
  object-fit: contain; opacity: 0; transition: opacity .25s ease;
  -webkit-user-drag: none; user-select: none; pointer-events: none;
}
.page.loaded .page-img { opacity: 1; }
/* images within ~2% of the page ratio fill the page edge-to-edge (no hairline gaps) */
.page.fit-fill .page-img { object-fit: fill; }
.page.instant .page-img { transition: none; }

/* Loading skeleton + error placeholder */
.page-ph {
  position: absolute; inset: 0; z-index: 1; display: grid; place-items: center; align-content: center; gap: .6rem;
  background: linear-gradient(105deg, var(--ph-a) 20%, var(--ph-b) 40%, var(--ph-a) 60%) 0 0 / 250% 100%;
  animation: shimmer 1.5s linear infinite;
  color: var(--text-dim); text-align: center; padding: 1rem;
}
.page-ph .label { font-size: .8rem; letter-spacing: .08em; text-transform: uppercase; }
.spinner {
  width: 2.2rem; height: 2.2rem; border-radius: 50%;
  border: 3px solid var(--surface-2); border-top-color: var(--accent);
  animation: spin .8s linear infinite;
}
.page-ph.error { animation: none; background: var(--ph-a); }
.page-ph.error svg { width: 2.4rem; height: 2.4rem; stroke: currentColor; fill: none; stroke-width: 1.6; }
.page-ph .retry {
  border: 1px solid var(--border); background: var(--surface-2); border-radius: 2rem;
  padding: .35rem 1rem; font-size: .85rem;
}
@keyframes spin { to { transform: rotate(360deg); } }
@keyframes shimmer { to { background-position: -150% 0; } }

/* Hover chevrons shown over the clickable page edges */
.edge-hint {
  position: fixed; top: 50%; z-index: 4; width: 3rem; height: 3rem; margin-top: -1.5rem;
  display: grid; place-items: center; border-radius: 50%; pointer-events: none;
  background: var(--surface); border: 1px solid var(--border);
  opacity: 0; transition: opacity .2s;
}
.edge-hint svg { width: 1.4rem; height: 1.4rem; }
.edge-hint.left { left: .75rem; } .edge-hint.right { right: .75rem; }
.stage[data-zone="left"] ~ .edge-hint.left, .stage[data-zone="right"] ~ .edge-hint.right { opacity: .9; }

/* ---------- 4. Page turn ---------- */
.leaf {
  position: absolute; top: 0; width: var(--pw); height: var(--ph); z-index: 5;
  transform-style: preserve-3d; -webkit-transform-style: preserve-3d; will-change: transform;
}
.leaf-fwd { left: var(--pw); transform-origin: left center; }
.leaf-back { left: 0; transform-origin: right center; }
.leaf-single { left: 0; transform-origin: left center; }
.leaf-face {
  position: absolute; inset: 0; overflow: hidden;
  backface-visibility: hidden; -webkit-backface-visibility: hidden;
}
.leaf-face.back { transform: rotateY(180deg); }
.leaf .shade { position: absolute; inset: 0; z-index: 3; pointer-events: none; opacity: 0; }
/* shading ramps darker towards the free (outer) edge of the turning leaf */
.leaf-fwd .front .shade, .leaf-single .front .shade, .leaf-back .back .shade {
  background: linear-gradient(to right, rgba(0,0,0,.04), rgba(0,0,0,.5));
}
.leaf-fwd .back .shade, .leaf-back .front .shade {
  background: linear-gradient(to right, rgba(0,0,0,.5), rgba(0,0,0,.04));
}
/* shadow cast by the leaf onto the pages beneath it */
.cast { position: absolute; top: 0; width: var(--pw); height: var(--ph); z-index: 4; pointer-events: none; opacity: 0; }
.cast-l { left: 0; background: linear-gradient(to left, rgba(0,0,0,.5), rgba(0,0,0,0) 70%); }
.cast-r { left: var(--pw); background: linear-gradient(to right, rgba(0,0,0,.5), rgba(0,0,0,0) 70%); }
.book.single .cast { display: none; }

/* Page curl (peeling corner + diagonal fold) */
.curl { position: absolute; top: 0; width: var(--pw); height: var(--ph); z-index: 5; pointer-events: none; }
.curl-part { position: absolute; inset: 0; }
.curl-flapwrap { filter: drop-shadow(0 6px 10px rgba(0, 0, 0, .38)); }
.curl-flap { position: absolute; left: 0; top: 0; width: var(--pw); height: var(--ph); transform-origin: 0 0; will-change: transform; }
.curl-grad { position: absolute; left: 0; top: 0; transform-origin: 0 0; pointer-events: none; }

/* ---------- 5. Bars & controls ---------- */
.bar {
  position: fixed; left: 0; right: 0; z-index: 20;
  display: flex; align-items: center; gap: .6rem;
  background: var(--surface); color: var(--text);
  -webkit-backdrop-filter: blur(16px) saturate(1.3); backdrop-filter: blur(16px) saturate(1.3);
  transition: transform .35s ease, opacity .35s ease, visibility 0s 0s;
}
.topbar {
  top: 0; padding: .5rem .8rem; padding-top: calc(.5rem + env(safe-area-inset-top));
  padding-left: calc(.8rem + env(safe-area-inset-left)); padding-right: calc(.8rem + env(safe-area-inset-right));
  border-bottom: 1px solid var(--border);
}
.toolbar {
  bottom: 0; flex-wrap: wrap; justify-content: center; row-gap: .35rem;
  padding: .5rem .8rem; padding-bottom: calc(.5rem + env(safe-area-inset-bottom));
  padding-left: calc(.8rem + env(safe-area-inset-left)); padding-right: calc(.8rem + env(safe-area-inset-right));
  border-top: 1px solid var(--border);
}
.ui-hidden .topbar, .ui-hidden .toolbar { opacity: 0; pointer-events: none; visibility: hidden; transition: transform .35s ease, opacity .35s ease, visibility 0s .35s; }
.ui-hidden .topbar { transform: translateY(-100%); }
.ui-hidden .toolbar { transform: translateY(100%); }

.titles { flex: 1 1 auto; min-width: 0; line-height: 1.2; }
.titles h1 { margin: 0; font: 700 1.05rem Georgia, "Times New Roman", serif; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.titles p { margin: .1rem 0 0; font-size: .78rem; color: var(--text-dim); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.bar-actions, .group { display: flex; align-items: center; gap: .25rem; }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .4rem;
  min-width: 2.5rem; height: 2.5rem; padding: 0 .55rem; border-radius: .7rem;
  background: transparent; border: 1px solid transparent; color: var(--text);
  text-decoration: none; transition: background .15s, border-color .15s, transform .1s;
}
.btn:hover { background: var(--surface-2); }
.btn:active { transform: scale(.95); }
.btn[aria-pressed="true"], .btn[aria-expanded="true"] { background: var(--surface-2); border-color: var(--border); color: var(--accent); }
.btn[aria-disabled="true"] { opacity: .35; cursor: default; pointer-events: none; }
.btn[hidden] { display: none; }
.btn svg { width: 1.3rem; height: 1.3rem; flex: none; fill: none; stroke: currentColor; stroke-width: 1.9; stroke-linecap: round; stroke-linejoin: round; }
.btn .btn-label { font-size: .82rem; }
.btn.primary { background: var(--accent); color: var(--accent-ink); }
.btn.primary:hover { filter: brightness(1.08); background: var(--accent); }
.theme-sun { display: none; }
:root[data-theme="light"] .theme-moon { display: none; }
:root[data-theme="light"] .theme-sun { display: inline; }
.fs-exit { display: none; }
.is-fullscreen .fs-enter { display: none; }
.is-fullscreen .fs-exit { display: inline; }

/* page counter + jump input */
.pager { display: flex; align-items: center; gap: .15rem; }
.jump { display: flex; align-items: baseline; gap: .35rem; margin: 0 .35rem; font-variant-numeric: tabular-nums; white-space: nowrap; }
.jump input {
  width: 4.6ch; min-width: 4.6ch; height: 2rem; text-align: center; font-weight: 600;
  background: var(--surface-2); border: 1px solid var(--border); border-radius: .5rem;
}
.jump input.shake { animation: shake .3s; border-color: #e5484d; }
.jump .total { color: var(--text-dim); font-size: .92rem; }
@keyframes shake { 25% { transform: translateX(-4px); } 75% { transform: translateX(4px); } }

/* progress slider */
.scrub { flex: 1 1 12rem; min-width: 9rem; max-width: 34rem; display: flex; align-items: center; }
input[type="range"].slider {
  -webkit-appearance: none; appearance: none; width: 100%; height: 1.8rem; background: transparent; margin: 0; cursor: pointer;
  --fill: 0%;
}
.slider::-webkit-slider-runnable-track {
  height: .3rem; border-radius: 1rem;
  background: linear-gradient(to right, var(--accent) var(--fill), var(--surface-2) var(--fill));
  border: 1px solid var(--border);
}
.slider::-moz-range-track { height: .3rem; border-radius: 1rem; background: var(--surface-2); border: 1px solid var(--border); }
.slider::-moz-range-progress { height: .3rem; border-radius: 1rem; background: var(--accent); }
.slider::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none; width: 1.15rem; height: 1.15rem; margin-top: -.5rem;
  border-radius: 50%; background: var(--accent); border: 2px solid var(--surface-solid); box-shadow: 0 1px 6px rgba(0,0,0,.5);
}
.slider::-moz-range-thumb { width: 1rem; height: 1rem; border-radius: 50%; background: var(--accent); border: 2px solid var(--surface-solid); }

/* ---------- 6. Thumbnails ---------- */
.thumbs {
  position: fixed; z-index: 15; display: flex; flex-direction: column;
  background: var(--surface-solid); border: 0 solid var(--border);
  transition: transform .3s ease, opacity .3s ease, visibility 0s 0s;
}
.thumbs:not(.open) { visibility: hidden; opacity: 0; transition: transform .3s ease, opacity .3s ease, visibility 0s .3s; }
.thumbs-head { display: flex; align-items: center; justify-content: space-between; padding: .35rem .5rem .35rem .8rem; border-bottom: 1px solid var(--border); font-weight: 600; font-size: .85rem; flex: none; }
.thumb-list { position: relative; flex: 1; overflow: auto; padding: .6rem; display: grid; gap: .6rem; overscroll-behavior: contain; -webkit-overflow-scrolling: touch; }
.thumb {
  position: relative; display: block; padding: 0; background: none; border: 2px solid transparent; border-radius: .4rem; text-align: center;
}
.thumb-frame { display: block; position: relative; aspect-ratio: var(--ratio, .77); background: linear-gradient(105deg, var(--ph-a) 20%, var(--ph-b) 40%, var(--ph-a) 60%) 0 0 / 250% 100%; border-radius: 2px; overflow: hidden; box-shadow: 0 4px 12px rgba(0,0,0,.35); }
.thumb-frame img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: contain; background: #fff; opacity: 0; transition: opacity .2s; -webkit-user-drag: none; }
.thumb-frame img.on { opacity: 1; }
.thumb-num { display: block; margin-top: .25rem; font-size: .75rem; color: var(--text-dim); font-variant-numeric: tabular-nums; }
.thumb:hover .thumb-frame { outline: 2px solid var(--surface-2); }
.thumb.current { border-color: var(--accent); }
.thumb.current .thumb-num { color: var(--accent); font-weight: 700; }

/* docked at the left on wide landscape screens … */
[data-dock="side"] .thumbs {
  left: 0; top: var(--top-h); bottom: var(--bottom-h); width: var(--thumbs-w);
  border-right-width: 1px; transform: translateX(-100%);
}
[data-dock="side"] .thumb-list { grid-template-columns: repeat(2, 1fr); align-content: start; }
/* … and as a strip above the toolbar on phones / portrait */
[data-dock="bottom"] .thumbs {
  left: 0; right: 0; bottom: var(--bottom-h); height: var(--thumbs-h); border-top-width: 1px; transform: translateY(100%);
}
[data-dock="bottom"] .thumb-list { grid-auto-flow: column; grid-auto-columns: calc((var(--thumbs-h) - 4.6rem) * var(--ratio, .77)); overflow-x: auto; overflow-y: hidden; }
[data-dock="bottom"] .thumbs-head { padding-top: .1rem; padding-bottom: .1rem; }
.thumbs.open { transform: none !important; }
.ui-hidden[data-dock="bottom"] .thumbs.open:not(:hover):not(:focus-within) { transform: translateY(100%) !important; opacity: 0; visibility: hidden; transition: transform .35s, opacity .35s, visibility 0s .35s; }

/* ---------- 7. Overlays ---------- */
.boot {
  position: fixed; inset: 0; z-index: 50; display: grid; place-content: center; justify-items: center; gap: 1rem;
  background: var(--bg); text-align: center; padding: 2rem; transition: opacity .4s, visibility 0s .4s;
}
.boot.done { opacity: 0; visibility: hidden; pointer-events: none; }
.boot .spinner { width: 3rem; height: 3rem; }
.boot h2 { margin: 0; font: 700 1.3rem Georgia, serif; }
.boot p { margin: 0; color: var(--text-dim); max-width: 34rem; }
.boot code { background: var(--surface-2); padding: .1rem .4rem; border-radius: .3rem; }
.toast {
  position: fixed; left: 50%; bottom: calc(var(--bottom-h) + 1rem); z-index: 40; transform: translate(-50%, 20px);
  background: var(--surface-solid); color: var(--text); border: 1px solid var(--border); border-radius: 2rem;
  padding: .55rem 1.1rem; font-size: .9rem; box-shadow: 0 8px 30px rgba(0,0,0,.4);
  opacity: 0; pointer-events: none; transition: opacity .25s, transform .25s; max-width: 90vw; text-align: center;
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }
.noscript { padding: 2rem; text-align: center; }

/* ---------- 8. Responsive / motion ---------- */
@media (max-width: 640px) {
  .toolbar { gap: .35rem; }
  .scrub { order: -1; flex-basis: 100%; max-width: none; }
  .btn .btn-label { display: none; }
  .btn { min-width: 2.4rem; }
  .jump { margin: 0 .1rem; }
}
@media (max-width: 360px) {
  .btn { min-width: 2.15rem; padding: 0 .35rem; }
  .titles h1 { font-size: .95rem; }
  .jump input { width: 4ch; min-width: 4ch; }
}
@media (max-height: 480px) {
  .toolbar { padding-top: .25rem; padding-bottom: calc(.25rem + env(safe-area-inset-bottom)); }
  .topbar { padding-top: calc(.25rem + env(safe-area-inset-top)); padding-bottom: .25rem; }
  .btn { height: 2.2rem; }
}
@media (hover: none) { .edge-hint { display: none; } }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .001ms !important; animation-iteration-count: 1 !important; transition-duration: .001ms !important; scroll-behavior: auto !important; }
  .spinner { animation: spin 1.6s linear infinite !important; animation-duration: 1.6s !important; animation-iteration-count: infinite !important; }
}
@media (forced-colors: active) { .btn { border-color: ButtonText; } }