@font-face {
  font-family: "Inter";
  src: url("../fonts/inter-latin.woff2") format("woff2");
  font-weight: 100 900;
  font-display: swap;
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
@font-face {
  font-family: "Inter";
  src: url("../fonts/inter-latin-ext.woff2") format("woff2");
  font-weight: 100 900;
  font-display: swap;
  unicode-range: U+0100-02AF, U+0304, U+0308, U+0329, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
@font-face {
  font-family: "Inter";
  src: url("../fonts/inter-cyrillic.woff2") format("woff2");
  font-weight: 100 900;
  font-display: swap;
  unicode-range: U+0301, U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
}

/* ---------- themes ---------- */
:root {
  --bg: #000;
  --bg-glow: #1c1c1e;
  --text: #f5f5f7;
  --muted: rgba(245, 245, 247, 0.6);
  --glass: rgba(255, 255, 255, 0.08);
  --glass-hover: rgba(255, 255, 255, 0.14);
  --edge: rgba(255, 255, 255, 0.14);
  --solid: #f5f5f7;
  --on-solid: #000;
  --panel: rgba(28, 28, 30, 0.86);
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}
html[data-theme="day"] {
  --bg: #e9e9ed;
  --bg-glow: #ffffff;
  --text: #1d1d1f;
  --muted: rgba(29, 29, 31, 0.58);
  --glass: rgba(255, 255, 255, 0.6);
  --glass-hover: rgba(255, 255, 255, 0.85);
  --edge: rgba(0, 0, 0, 0.1);
  --solid: #1d1d1f;
  --on-solid: #fff;
  --panel: rgba(255, 255, 255, 0.86);
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.12);
}
:root {
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --font: "Inter", -apple-system, "SF Pro Text", "Segoe UI", Roboto, Arial, sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font);
  -webkit-user-select: none;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.6s var(--ease), color 0.6s var(--ease);
}

/* Smooth background: a soft light behind the folders, plus a faint film grain that hides colour banding. */
body::before,
body::after {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
}
body::before {
  background: radial-gradient(ellipse 75% 60% at 50% 40%, var(--bg-glow) 0%, var(--bg) 72%);
  transition: background 0.6s var(--ease);
}
body::after {
  opacity: 0.05;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='200' height='200'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/><feColorMatrix values='0 0 0 0 0.5  0 0 0 0 0.5  0 0 0 0 0.5  0 0 0 1 0'/></filter><rect width='200' height='200' filter='url(%23n)'/></svg>");
}

#scene {
  position: fixed;
  inset: 0;
  z-index: 1;
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
  cursor: grab;
}
#scene:active { cursor: grabbing; }

/* ---------- glass surfaces ---------- */
.btn,
.tab,
.hint,
.settings {
  background: var(--glass);
  border: 1px solid var(--edge);
  box-shadow: var(--shadow);
  -webkit-backdrop-filter: blur(20px) saturate(160%);
  backdrop-filter: blur(20px) saturate(160%);
}
.lite .btn, .lite .tab, .lite .hint, .lite .settings { -webkit-backdrop-filter: none; backdrop-filter: none; background: var(--panel); }

/* ---------- top bar ---------- */
.topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 18px 24px;
  pointer-events: none;
  z-index: 5;
}
.topbar > * { pointer-events: auto; }
.brand { display: flex; flex-direction: column; transition: opacity 0.6s var(--ease), transform 0.6s var(--ease); }
.brand-title { font-size: clamp(20px, 2.2vw, 28px); font-weight: 700; letter-spacing: -0.02em; }
.brand-sub { font-size: clamp(12px, 1.1vw, 15px); color: var(--muted); }
.top-actions { display: flex; gap: 10px; }
.is-open .brand { opacity: 0; transform: translateY(-8px); }

/* ---------- buttons (big, for touch boards) ---------- */
.btn {
  font: inherit;
  font-weight: 500;
  font-size: clamp(15px, 1.35vw, 19px);
  min-height: 52px;
  padding: 10px 22px;
  border-radius: 999px;
  color: var(--text);
  cursor: pointer;
  touch-action: manipulation;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  transition: background 0.25s var(--ease), transform 0.25s var(--ease), opacity 0.25s, color 0.6s var(--ease);
}
.btn:hover { background: var(--glass-hover); }
.btn:active { transform: scale(0.95); }
.btn:disabled { opacity: 0.35; cursor: default; }
.btn:focus-visible { outline: 2px solid var(--text); outline-offset: 3px; }
.btn.icon { width: 52px; padding: 0; }
.btn.icon.on { background: var(--solid); color: var(--on-solid); }
.btn.round { width: 58px; height: 58px; padding: 0; font-size: 18px; }
.btn.primary,
.btn.action {
  background: var(--solid);
  color: var(--on-solid);
  border-color: transparent;
  font-weight: 600;
}
.btn.primary { min-width: 230px; }
.btn.primary:hover, .btn.action:hover { opacity: 0.88; background: var(--solid); }
.btn.action {
  font-size: clamp(17px, 1.6vw, 22px);
  padding: 12px 34px;
  opacity: 0;
  transform: translateY(10px) scale(0.96);
  pointer-events: none;
}
.btn.action.show { opacity: 1; transform: none; pointer-events: auto; }

/* ---------- settings panel ---------- */
.settings {
  position: fixed;
  top: 82px;
  right: 24px;
  z-index: 60;
  width: min(360px, calc(100vw - 32px));
  padding: 18px;
  border-radius: 22px;
  background: var(--panel);
  color: var(--text);
  opacity: 0;
  transform: translateY(-8px) scale(0.98);
  transform-origin: top right;
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease);
}
.settings.show { opacity: 1; transform: none; }
.set-label { font-size: 13px; font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase; color: var(--muted); margin: 14px 2px 8px; }
.set-label:first-child { margin-top: 0; }
.row-between { display: flex; justify-content: space-between; }
.set-note { font-size: 12px; color: var(--muted); margin: 8px 2px 0; line-height: 1.4; }
.seg {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 1fr;
  gap: 4px;
  padding: 4px;
  border-radius: 14px;
  background: var(--glass);
  border: 1px solid var(--edge);
}
.seg button {
  font: inherit;
  font-size: 15px;
  font-weight: 500;
  min-height: 44px;
  border: 0;
  border-radius: 10px;
  background: transparent;
  color: var(--text);
  cursor: pointer;
  transition: background 0.2s var(--ease), color 0.2s var(--ease);
}
.seg button.on { background: var(--solid); color: var(--on-solid); }
.seg .ico { font-size: 14px; }
input[type="range"] {
  width: 100%;
  height: 32px;
  accent-color: var(--solid);
  cursor: pointer;
}

/* ---------- bottom bars ---------- */
.bar {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 12px 16px 22px;
  z-index: 5;
  transition: opacity 0.5s var(--ease), transform 0.5s var(--ease);
}
.row { display: flex; align-items: center; justify-content: center; gap: 12px; flex-wrap: wrap; }

.open-only { opacity: 0; transform: translateY(24px); pointer-events: none; }
.is-open .open-only { opacity: 1; transform: none; pointer-events: auto; transition-delay: 0.35s; }
.is-open .carousel-only { opacity: 0; transform: translateY(24px); pointer-events: none; }

/* caption under the front folder, like the reference carousel */
.caption {
  position: fixed;
  left: 0; right: 0;
  bottom: 168px;
  z-index: 4;
  text-align: center;
  pointer-events: none;
  transition: opacity 0.5s var(--ease), transform 0.5s var(--ease);
}
.cap-title { font-size: clamp(16px, 1.5vw, 21px); font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; }
.cap-sub { font-size: clamp(13px, 1.15vw, 16px); color: var(--muted); margin-top: 4px; }
.caption .cap-title, .caption .cap-sub { opacity: 0; transform: translateY(6px); }
.caption.in .cap-title, .caption.in .cap-sub { opacity: 1; transform: none; transition: opacity 0.6s var(--ease), transform 0.6s var(--ease); }
.caption.in .cap-sub { transition-delay: 0.08s; }

.tabs {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
  max-width: 1150px;
}
.tab {
  --tab: #888;
  font: inherit;
  font-weight: 500;
  font-size: clamp(13px, 1.05vw, 15px);
  min-height: 40px;
  padding: 6px 16px 6px 12px;
  border-radius: 999px;
  color: var(--muted);
  cursor: pointer;
  touch-action: manipulation;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  box-shadow: none;
  transition: background 0.35s var(--ease), color 0.35s var(--ease);
}
.tab::before {
  content: "";
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--tab);
}
.tab:hover { color: var(--text); }
.tab.active { color: var(--on-solid); background: var(--solid); border-color: transparent; }

.page-info { text-align: center; min-width: 210px; padding: 0 8px; }
.folder-name { font-weight: 600; font-size: clamp(15px, 1.3vw, 18px); }
.page-count { color: var(--muted); font-size: clamp(13px, 1.05vw, 15px); }

.hint {
  position: fixed;
  top: 84px;
  left: 50%;
  transform: translateX(-50%);
  padding: 9px 20px;
  border-radius: 999px;
  color: var(--text);
  font-size: clamp(13px, 1.1vw, 15px);
  white-space: nowrap;
  z-index: 4;
  box-shadow: none;
  transition: opacity 0.8s var(--ease), transform 0.8s var(--ease);
  pointer-events: none;
}
.hint.gone, .is-open .hint { opacity: 0; transform: translate(-50%, -8px); }

/* ---------- full-screen viewer ---------- */
.viewer {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: flex;
  flex-direction: column;
  background: rgba(0, 0, 0, 0.94);
  color: #f5f5f7;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.4s var(--ease), visibility 0s linear 0.4s;
}
.viewer .btn { color: #f5f5f7; background: rgba(255, 255, 255, 0.1); border-color: rgba(255, 255, 255, 0.16); }
.viewer.open { opacity: 1; visibility: visible; transition: opacity 0.4s var(--ease); }
.viewer-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 22px;
}
.viewer-title { font-size: clamp(17px, 1.6vw, 22px); font-weight: 600; }
.viewer-stage {
  flex: 1;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 20px 18px;
  transform: scale(0.97);
  transition: transform 0.5s var(--ease);
}
.viewer.open .viewer-stage { transform: none; }
.viewer-stage video,
.viewer-stage img,
.viewer-stage canvas {
  max-width: 100%;
  max-height: 100%;
  border-radius: 14px;
  background: #000;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.6);
}
.viewer-stage iframe { width: 100%; height: 100%; border: 0; border-radius: 14px; background: #fff; }
.viewer-msg { color: rgba(245, 245, 247, 0.6); font-size: 20px; text-align: center; max-width: 640px; line-height: 1.5; }
.viewer-nav { display: none; align-items: center; justify-content: center; gap: 16px; padding: 0 16px 20px; }
.viewer.has-nav .viewer-nav { display: flex; }
.viewer-count { color: rgba(245, 245, 247, 0.6); min-width: 80px; text-align: center; font-size: 18px; }

/* ---------- misc ---------- */
.dim {
  position: fixed;
  inset: 0;
  z-index: 50;
  background: #000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s linear;
}
.drop {
  position: fixed;
  inset: 16px;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 28px;
  background: var(--panel);
  border: 2px dashed var(--text);
  font-size: 26px;
  font-weight: 600;
}
.drop[hidden], .loading[hidden], .settings[hidden] { display: none; }
.loading {
  position: fixed;
  inset: 0;
  z-index: 70;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 24px;
  line-height: 1.6;
  font-size: 20px;
  background: var(--bg);
  transition: opacity 0.9s var(--ease), visibility 0s linear 0.9s;
}
.loading.done { opacity: 0; visibility: hidden; }
.spinner {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 2px solid var(--edge);
  border-top-color: var(--text);
  animation: spin 0.9s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

@media (max-width: 700px) {
  .brand-sub, .hint { display: none; }
  .btn { min-height: 46px; padding: 8px 16px; }
  .btn.icon { width: 46px; }
  .btn.primary { min-width: 0; }
  .btn.round { width: 50px; height: 50px; }
  .page-info { min-width: 0; order: -1; width: 100%; }
  #btn-add { font-size: 14px; }
  .caption { bottom: 150px; }
}
@media (max-height: 600px) {
  .tabs, .caption { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition-duration: 0.01s !important; animation-duration: 0.01s !important; }
}