:root {
  color-scheme: light;
  --bg1: #fff7e8;
  --bg2: #dff3ff;
  --panel: rgba(255, 255, 255, 0.82);
  --text: #203040;
  --muted: #5f7386;
  --shadow: 0 18px 40px rgba(39, 68, 94, 0.15);
  --recyclable: #42a85f;
  --kitchen: #e49a2e;
  --hazardous: #d65757;
  --other: #5a6fd6;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, #fffbe8 0%, transparent 35%),
    radial-gradient(circle at top right, #d8f1ff 0%, transparent 30%),
    linear-gradient(180deg, var(--bg1), var(--bg2));
}

body {
  min-height: 100vh;
}

.app {
  width: min(1200px, calc(100vw - 24px));
  margin: 0 auto;
  padding: 18px 0 26px;
}

.hud {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
  margin-bottom: 14px;
  flex-wrap: wrap;
}

.hud-right {
  display: flex;
  gap: 12px;
  align-items: center;
}

.brand h1 {
  margin: 2px 0 0;
  font-size: clamp(1.7rem, 4vw, 3rem);
  letter-spacing: 0.02em;
}

.eyebrow {
  margin: 0;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  color: #5e7e8f;
  text-transform: uppercase;
}

.stats {
  display: flex;
  gap: 12px;
}

.stat {
  min-width: 132px;
  padding: 14px 16px;
  background: var(--panel);
  border: 1px solid rgba(255, 255, 255, 0.75);
  border-radius: 18px;
  box-shadow: var(--shadow);
  text-align: center;
}

.label {
  display: block;
  font-size: 0.86rem;
  color: var(--muted);
  margin-bottom: 4px;
}

.stat strong {
  font-size: 1.6rem;
}

.playground {
  position: relative;
  overflow: hidden;
  min-height: clamp(560px, 72vh, 780px);
  border-radius: 28px;
  border: 2px solid rgba(255, 255, 255, 0.7);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.5), rgba(255, 255, 255, 0.1)),
    linear-gradient(180deg, #dff8ff 0%, #edf9e6 46%, #fef2d2 100%);
  box-shadow: var(--shadow);
}

.sky {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 20% 20%, rgba(255, 255, 255, 0.9) 0 8%, transparent 9%),
    radial-gradient(circle at 80% 18%, rgba(255, 255, 255, 0.85) 0 10%, transparent 11%);
  opacity: 0.45;
  pointer-events: none;
}

.cloud {
  position: absolute;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.66);
  filter: blur(1px);
  pointer-events: none;
}

.cloud::before,
.cloud::after {
  content: "";
  position: absolute;
  border-radius: inherit;
  background: inherit;
}

.cloud-a {
  width: 150px;
  height: 52px;
  left: 10%;
  top: 12%;
}

.cloud-a::before {
  width: 64px;
  height: 64px;
  left: 18px;
  top: -24px;
}

.cloud-a::after {
  width: 76px;
  height: 76px;
  right: 16px;
  top: -30px;
}

.cloud-b {
  width: 120px;
  height: 46px;
  right: 12%;
  top: 18%;
}

.cloud-b::before {
  width: 54px;
  height: 54px;
  left: 12px;
  top: -22px;
}

.cloud-b::after {
  width: 62px;
  height: 62px;
  right: 10px;
  top: -28px;
}

.hint {
  position: absolute;
  top: 18px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
  align-items: center;
  padding: 10px 16px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.78);
  box-shadow: 0 8px 22px rgba(0, 0, 0, 0.07);
  font-weight: 700;
  z-index: 2;
}

.hint span + span::before {
  content: "·";
  margin-right: 10px;
  color: #90a4b4;
}

.item-card {
  position: absolute;
  left: 50%;
  top: clamp(60px, 8vh, 110px);
  width: min(280px, 56vw);
  transform: translateX(-50%);
  padding: 18px 16px 16px;
  border-radius: 26px;
  background: rgba(255, 255, 255, 0.94);
  border: 2px solid rgba(255, 255, 255, 0.9);
  box-shadow: 0 16px 38px rgba(0, 0, 0, 0.12);
  text-align: center;
  will-change: transform;
  z-index: 3;
}

.item-icon {
  font-size: clamp(3rem, 7vw, 5rem);
  line-height: 1;
}

.item-name {
  margin-top: 8px;
  font-size: 1.35rem;
  font-weight: 800;
}

.item-category {
  margin-top: 4px;
  font-size: 0.95rem;
  color: var(--muted);
}

.message {
  position: absolute;
  left: 50%;
  top: 180px;
  transform: translateX(-50%);
  padding: 10px 18px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.88);
  font-weight: 700;
  box-shadow: 0 10px 22px rgba(0, 0, 0, 0.08);
  z-index: 3;
}

.message.good {
  color: var(--recyclable);
}

.message.bad {
  color: var(--hazardous);
}

.message.info {
  color: var(--muted);
}

.bin-row {
  position: absolute;
  left: 50%;
  bottom: 16px;
  transform: translateX(-50%);
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
  width: min(100%, 1140px);
  padding: 0 16px;
  z-index: 4;
}

.bin {
  appearance: none;
  border: none;
  border-radius: 24px;
  min-height: 160px;
  padding: 16px 12px 14px;
  color: white;
  box-shadow: 0 16px 28px rgba(0, 0, 0, 0.14);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  justify-content: end;
  gap: 4px;
  text-align: center;
  transition: transform 160ms ease, filter 160ms ease, box-shadow 160ms ease;
}

.bin:hover,
.bin:focus-visible {
  transform: translateY(-6px);
  filter: brightness(1.02);
  outline: none;
}

.bin:active {
  transform: translateY(-2px) scale(0.99);
}

.bin-icon {
  font-size: 2.4rem;
  margin-bottom: auto;
}

.bin-key {
  display: inline-grid;
  place-items: center;
  width: 34px;
  height: 34px;
  margin: 0 auto 2px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.24);
  font-size: 1rem;
  font-weight: 900;
  letter-spacing: 0.03em;
}

.bin-name {
  font-size: 1.2rem;
  font-weight: 800;
}

.bin-tip {
  font-size: 0.9rem;
  line-height: 1.35;
  opacity: 0.95;
}

.recyclable {
  background: linear-gradient(180deg, #52c76f, #2f8c49);
}

.kitchen {
  background: linear-gradient(180deg, #ffbf57, #cf7d09);
}

.hazardous {
  background: linear-gradient(180deg, #ef7070, #b83c3c);
}

.other {
  background: linear-gradient(180deg, #7488ff, #4d61d0);
}

.rules {
  margin-top: 14px;
  display: grid;
  grid-template-columns: 1fr;
}

.back-home {
  margin: 14px 0 0;
  text-align: center;
}

.back-home a {
  display: inline-block;
  border-radius: 999px;
  padding: 11px 16px;
  background: rgba(255, 255, 255, 0.82);
  border: 1px solid rgba(255, 255, 255, 0.9);
  box-shadow: 0 10px 22px rgba(39, 68, 94, 0.12);
  color: var(--text);
  font-weight: 700;
  text-decoration: none;
  transition: transform 160ms ease, filter 160ms ease;
}

.back-home a:hover,
.back-home a:focus-visible {
  transform: translateY(-2px);
  filter: brightness(1.02);
  outline: none;
}

.rule-card {
  padding: 16px 18px;
  border-radius: 20px;
  background: var(--panel);
  border: 1px solid rgba(255, 255, 255, 0.75);
  box-shadow: var(--shadow);
}

.rule-card strong {
  display: block;
  margin-bottom: 6px;
  font-size: 1.05rem;
}

.rule-card p {
  margin: 0;
  color: var(--muted);
  line-height: 1.65;
}

.overlay {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  background: rgba(13, 24, 36, 0.42);
  backdrop-filter: blur(6px);
  z-index: 10;
}

.overlay[hidden] {
  display: none;
}

.overlay-card {
  width: min(92vw, 860px);
  max-height: 90vh;
  overflow-y: auto;
  padding: 30px 24px 26px;
  text-align: center;
  border-radius: 28px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 0 24px 50px rgba(0, 0, 0, 0.2);
}

.overlay-title {
  margin: 0 0 8px;
  font-size: 1.7rem;
  font-weight: 900;
}

.overlay-score {
  margin: 0 0 18px;
  font-size: 1.1rem;
  color: var(--muted);
}

.mistakes-section {
  margin: 18px 0;
  padding: 0 12px;
  border-top: 1px solid rgba(0, 0, 0, 0.08);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
}

.mistakes-title {
  margin: 12px 0 12px;
  font-size: 1rem;
  font-weight: 800;
  color: var(--text);
  text-align: left;
}

.mistakes-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 12px;
}

.mistake-item {
  padding: 16px 12px;
  background: rgba(239, 112, 112, 0.08);
  border: 2px solid rgba(214, 87, 87, 0.3);
  border-radius: 16px;
  text-align: center;
  font-size: 0.9rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.mistake-item.perfect {
  background: rgba(42, 200, 95, 0.15);
  border-color: rgba(66, 168, 95, 0.4);
  font-weight: 700;
  color: var(--recyclable);
  font-size: 1rem;
  grid-column: 1 / -1;
  padding: 20px;
}

.mistake-item-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.mistake-icon {
  font-size: 2.2rem;
  line-height: 1;
}

.mistake-name {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text);
}

.mistake-chosen,
.mistake-correct {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 3px;
  font-size: 0.8rem;
  width: 100%;
}

.mistake-chosen .label,
.mistake-correct .label {
  color: var(--muted);
  font-weight: 600;
}

.category {
  padding: 2px 6px;
  border-radius: 5px;
  font-weight: 600;
  font-size: 0.8rem;
}

.category.wrong {
  background: rgba(214, 87, 87, 0.2);
  color: var(--hazardous);
}

.category.correct {
  background: rgba(66, 168, 95, 0.2);
  color: var(--recyclable);
}

.restart-btn {
  border: none;
  border-radius: 999px;
  padding: 14px 20px;
  min-width: 150px;
  background: linear-gradient(180deg, #2f8c49, #256e39);
  color: white;
  font-size: 1rem;
  font-weight: 800;
  cursor: pointer;
}

.restart-btn:focus-visible {
  outline: 3px solid rgba(66, 168, 95, 0.35);
  outline-offset: 3px;
}

.control-btn {
  border: none;
  border-radius: 999px;
  padding: 12px 20px;
  background: linear-gradient(180deg, #2f8c49, #256e39);
  color: white;
  font-size: 0.95rem;
  font-weight: 800;
  cursor: pointer;
  transition: filter 160ms ease, transform 160ms ease;
}

.control-btn:hover,
.control-btn:focus-visible {
  filter: brightness(1.08);
  outline: none;
}

.control-btn:active {
  transform: scale(0.98);
}

.control-btn.running {
  background: linear-gradient(180deg, #ef7070, #b83c3c);
}

@media (max-width: 900px) {
  .hud {
    flex-direction: column;
    align-items: stretch;
  }

  .hud-right {
    flex-direction: column;
  }

  .stats {
    justify-content: space-between;
  }

  .bin-row {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    bottom: 12px;
  }

  .bin {
    min-height: 132px;
  }

  .message {
    top: 160px;
  }
}

@media (max-width: 560px) {
  .app {
    width: min(100vw - 14px, 1200px);
    padding-top: 10px;
  }

  .stats {
    flex-direction: column;
  }

  .stat {
    min-width: 0;
  }

  .playground {
    min-height: 640px;
  }

  .hint {
    width: calc(100% - 18px);
    justify-content: center;
    gap: 8px;
    padding-inline: 12px;
    font-size: 0.9rem;
  }

  .hint span + span::before {
    margin-right: 6px;
  }

  .item-card {
    width: min(260px, 72vw);
  }

  .bin-row {
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    padding: 0 10px;
  }

  .bin {
    min-height: 118px;
    padding: 12px 10px 12px;
  }

  .bin-name {
    font-size: 1.02rem;
  }

  .bin-tip {
    font-size: 0.8rem;
  }
}