:root {
  --bg: #faf9f6;
  --ink: #141414;
  --paper: #ffffff;
  --panel-line: #111111;
  --accent-blue: #9bb8ff;
  --transition: 720ms cubic-bezier(0.22, 1, 0.36, 1);
  --main-panel-size: 260px;
  --option-panel-size: 170px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--bg);
}

.app-shell {
  width: min(1180px, calc(100vw - 64px));
  margin: 0 auto;
  padding: 52px 0 56px;
}

.story-stage {
  position: relative;
  overflow: visible;
  border-radius: 24px;
  background: transparent;
  min-height: calc(var(--main-panel-size) * 2 + var(--option-panel-size) + 40px);
}

.chapter-overview[hidden] {
  display: none;
}

.chapter-overview {
  padding: 8px 0 24px;
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 700ms ease, transform 700ms ease;
}

.chapter-overview.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.overview-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 36px;
}

.overview-chapter {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  justify-content: center;
}

.overview-label {
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: rgba(20, 20, 20, 0.7);
}

.overview-chapter .chapter-grid {
  transform: scale(0.72);
  transform-origin: top center;
  margin: 0;
}

.chapter-track {
  display: flex;
  align-items: stretch;
  gap: 0;
  transition: transform 1200ms cubic-bezier(0.2, 0.8, 0.2, 1);
  will-change: transform;
}

.chapter {
  position: relative;
  flex: 0 0 100%;
  width: 100%;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 48px;
  align-items: center;
}

.chapter-grid {
  display: grid;
  grid-template-columns: repeat(2, var(--main-panel-size));
  grid-template-rows: repeat(2, var(--main-panel-size));
  gap: 18px;
  width: fit-content;
  margin: 0 auto;
  overflow: visible;
  background: transparent;
  transition: transform var(--transition), opacity var(--transition);
}

.comic-panel {
  width: 100%;
  height: 100%;
  min-height: 0;
  position: relative;
  padding: 0;
  border-radius: 0;
  border: 4px solid var(--panel-line);
  background: #fbf7ed;
  box-shadow: none;
  overflow: hidden;
  opacity: 0;
  transform: translateY(18px) scale(0.98);
  transition:
    opacity 560ms ease,
    transform 560ms ease,
    border-color 220ms ease,
    background-color 220ms ease,
    box-shadow 220ms ease;
}

.comic-panel.is-visible {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.comic-panel.is-drop-target {
  background: #fbf7ed;
}

.comic-panel.is-over {
  box-shadow: inset 0 0 0 6px rgba(155, 184, 255, 0.2);
}

.comic-panel.is-empty .panel-art,
.comic-panel.is-empty::after {
  opacity: 0.42;
}

.comic-panel.is-option {
  width: var(--option-panel-size);
  height: var(--option-panel-size);
  cursor: grab;
  opacity: 1;
  transform: none;
  border-radius: 0;
  border-width: 3px;
  touch-action: none;
  user-select: none;
  transform-origin: center center;
  transition:
    transform 220ms cubic-bezier(0.22, 1, 0.36, 1),
    opacity 1200ms ease,
    filter 1200ms ease,
    border-color 220ms ease,
    box-shadow 220ms ease;
}

.comic-panel.is-option:active {
  cursor: grabbing;
}

.comic-panel.is-option:hover {
  border-color: #f0c64d;
  box-shadow: 0 18px 32px rgba(0, 0, 0, 0.16);
}

.comic-panel.is-option.is-hover-left {
  transform: scale(1.16);
}

.comic-panel.is-option.is-hover-right {
  transform: scale(1.16);
}

.comic-panel.is-option.is-hover-center {
  transform: scale(1.16);
}

.panel-art {
  height: 100%;
  min-height: 100%;
  border-radius: 0;
  overflow: hidden;
  background-position: center;
  background-size: cover;
  background-color: #e9dfca;
  transition:
    opacity 1100ms ease,
    filter 1100ms ease,
    transform 1100ms ease;
}

.option-strip {
  position: relative;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 420ms ease, transform 420ms ease;
}

.option-strip.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.option-strip__title {
  display: none;
}

.options {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 28px;
  width: fit-content;
  margin: 0 auto;
  justify-items: center;
}

.options.is-frozen {
  position: relative;
}

.options.is-frozen .comic-panel.is-option {
  position: absolute;
  margin: 0;
}

.comic-panel.is-option.is-dragging {
  opacity: 0;
}

.chapter.is-transitioning .option-strip {
  pointer-events: none;
}

.chapter.is-transitioning .comic-panel.is-option.is-used {
  opacity: 0;
  pointer-events: none;
}

.comic-panel.is-option.is-bursting {
  opacity: 0;
  filter: blur(20px);
  transform: translateY(-10px) scale(1.02);
  pointer-events: none;
}

.comic-panel.is-option.is-bursting .panel-art {
  opacity: 0.08;
  filter: blur(26px) saturate(0.92) brightness(1.05);
  transform: translateY(-8px) scale(1.06);
}

.particle {
  position: absolute;
  width: var(--w, 32px);
  height: var(--h, 18px);
  border-radius: 999px;
  background:
    radial-gradient(circle at center, rgba(255, 255, 255, 0.46), rgba(255, 255, 255, 0));
  opacity: 0;
  transform: translate3d(0, 0, 0) scale(0.92);
  filter: blur(6px);
  mix-blend-mode: screen;
  animation: feather-dissolve var(--duration, 1400ms) cubic-bezier(0.16, 0.84, 0.32, 1) forwards;
  pointer-events: none;
}

@keyframes feather-dissolve {
  0% {
    opacity: 0;
    transform: translate3d(0, 0, 0) scale(0.86);
    filter: blur(3px);
  }

  16% {
    opacity: 0.32;
  }

  55% {
    opacity: 0.18;
  }

  100% {
    opacity: 0;
    transform:
      translate3d(var(--dx, 0px), var(--dy, 0px), 0)
      scale(1.2);
    filter: blur(14px);
  }
}

.comic-panel.is-empty::after {
  content: "拖到这里";
  position: absolute;
  inset: auto 0 26px;
  text-align: center;
  font-size: 0.9rem;
  letter-spacing: 0.08em;
  color: rgba(20, 20, 20, 0.26);
}

@media (max-width: 920px) {
  :root {
    --main-panel-size: min(38vw, 220px);
    --option-panel-size: min(22vw, 150px);
  }

  .chapter.is-complete .chapter-grid {
    grid-template-columns: repeat(2, var(--main-panel-size));
    grid-template-rows: repeat(2, var(--main-panel-size));
  }

  .options {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }

}

@media (max-width: 560px) {
  :root {
    --main-panel-size: min(42vw, 180px);
    --option-panel-size: min(42vw, 150px);
  }

  .app-shell {
    width: min(100vw - 28px, 100%);
    padding-top: 24px;
  }

  .options {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
  }

  .comic-panel.is-option {
    width: var(--option-panel-size);
    height: var(--option-panel-size);
  }
}