:root {
  --bg-deep: #04121f;
  --bg-mid: #0a2135;
  --bg-light: #133a58;
  --panel: rgba(7, 24, 38, 0.8);
  --panel-border: rgba(123, 223, 255, 0.24);
  --text-main: #eaf7ff;
  --text-soft: #b2d0e1;
  --accent: #2adcb0;
  --accent-strong: #3ce7be;
  --warn: #ff9c6b;
  --danger: #ff6b76;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  font-family: "Sora", sans-serif;
  background: radial-gradient(circle at 10% 10%, var(--bg-light), var(--bg-deep) 55%, #02070d 100%);
  color: var(--text-main);
}

body {
  overflow: hidden;
}

.bg-shape {
  position: fixed;
  pointer-events: none;
  z-index: 0;
  border-radius: 50%;
  filter: blur(24px);
}

.bg-shape-a {
  width: 320px;
  height: 320px;
  background: rgba(60, 231, 190, 0.22);
  top: -70px;
  left: -40px;
}

.bg-shape-b {
  width: 420px;
  height: 420px;
  background: rgba(67, 146, 255, 0.18);
  bottom: -150px;
  right: -120px;
}

.bg-grid {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.22;
  background-image: linear-gradient(rgba(194, 235, 255, 0.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(194, 235, 255, 0.08) 1px, transparent 1px);
  background-size: 34px 34px;
  mask-image: radial-gradient(circle at 50% 42%, black 35%, transparent 85%);
}

#app {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 360px 1fr;
  height: 100vh;
  gap: 16px;
  padding: 16px;
}

#hud {
  overflow: auto;
  background: linear-gradient(180deg, rgba(7, 22, 34, 0.92), rgba(5, 17, 26, 0.78));
  border: 1px solid var(--panel-border);
  border-radius: 18px;
  padding: 16px;
  backdrop-filter: blur(12px);
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.35);
}

h1 {
  margin: 0;
  font-size: 1.9rem;
  letter-spacing: 0.01em;
  line-height: 1.05;
}

.subtitle {
  margin: 8px 0 14px;
  color: var(--text-soft);
  font-size: 0.93rem;
}

.panel {
  border: 1px solid rgba(123, 223, 255, 0.16);
  border-radius: 12px;
  background: var(--panel);
  padding: 12px;
  margin-bottom: 10px;
}

.panel h2 {
  margin: 0 0 8px;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #a9eaff;
}

.panel h3 {
  margin: 10px 0 8px;
  font-size: 0.85rem;
  color: #b4e8f8;
  letter-spacing: 0.04em;
}

.panel p {
  margin: 6px 0;
  color: #d5effc;
  font-size: 0.9rem;
}

.walkthrough-panel ol {
  margin: 0;
  padding-left: 20px;
}

.walkthrough-panel li {
  margin: 7px 0;
  color: #d5effc;
  font-size: 0.9rem;
  line-height: 1.35;
}

#challenge-name {
  font-size: 1.18rem;
  font-weight: 700;
  color: #fff;
}

#challenge-level,
#element-pool {
  font-size: 0.83rem;
  color: #b8d9e8;
}

#timer {
  color: #a4ffe7;
  font-family: "Space Mono", monospace;
}

.button-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.bottom-controls {
  margin-top: 10px;
}

.toggle-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
}

button {
  border: 1px solid rgba(134, 220, 255, 0.28);
  background: linear-gradient(180deg, rgba(16, 51, 77, 0.95), rgba(9, 31, 46, 0.95));
  color: var(--text-main);
  border-radius: 10px;
  padding: 9px 10px;
  font-family: "Space Mono", monospace;
  font-size: 0.83rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 120ms ease, border-color 120ms ease, box-shadow 120ms ease;
}

button:hover {
  transform: translateY(-1px);
  border-color: rgba(173, 238, 255, 0.62);
  box-shadow: 0 0 0 1px rgba(173, 238, 255, 0.22) inset;
}

button:active {
  transform: translateY(0);
}

button.active {
  border-color: rgba(82, 255, 208, 0.92);
  background: linear-gradient(180deg, rgba(20, 78, 74, 0.95), rgba(8, 45, 42, 0.95));
}

button.accent {
  border-color: rgba(84, 255, 210, 0.72);
  background: linear-gradient(180deg, rgba(31, 128, 100, 0.95), rgba(15, 73, 58, 0.95));
}

#add-carbon {
  border-color: rgba(220, 220, 220, 0.5);
  background: linear-gradient(180deg, rgba(38, 38, 38, 0.98), rgba(16, 16, 16, 0.98));
  color: #ffffff;
}

#add-hydrogen {
  border-color: rgba(230, 240, 255, 0.88);
  background: linear-gradient(180deg, rgba(252, 253, 255, 0.98), rgba(225, 232, 242, 0.98));
  color: #122133;
}

#add-hydrogen:hover {
  border-color: rgba(255, 255, 255, 0.98);
  box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.44) inset;
}

#untangle-btn {
  border-color: rgba(255, 205, 111, 0.72);
  background: linear-gradient(180deg, rgba(116, 81, 28, 0.95), rgba(73, 50, 15, 0.95));
}

#hint-btn {
  border-color: rgba(255, 167, 108, 0.72);
  background: linear-gradient(180deg, rgba(121, 61, 28, 0.95), rgba(77, 34, 11, 0.95));
}

#hint-readout {
  margin: 10px 0 0;
  min-height: 48px;
  border: 1px solid rgba(255, 175, 120, 0.42);
  border-radius: 10px;
  background: rgba(33, 17, 7, 0.6);
  padding: 8px 10px;
  font-size: 0.84rem;
  color: #ffe5c9;
}

.summary-panel p {
  font-size: 0.84rem;
}

#status {
  margin: 10px 0 0;
  min-height: 42px;
  border: 1px solid rgba(114, 208, 255, 0.22);
  border-radius: 10px;
  background: rgba(6, 20, 31, 0.72);
  padding: 10px;
  font-size: 0.9rem;
  color: var(--text-main);
}

#status.ok {
  border-color: rgba(74, 255, 199, 0.6);
  color: #b5ffe8;
}

#status.bad {
  border-color: rgba(255, 112, 123, 0.58);
  color: #ffc7ce;
}

#status.warn {
  border-color: rgba(255, 166, 117, 0.55);
  color: #ffd8c0;
}

#scene-wrap {
  position: relative;
  border-radius: 20px;
  border: 1px solid rgba(152, 218, 246, 0.22);
  overflow: hidden;
  min-height: 400px;
  box-shadow: inset 0 0 36px rgba(20, 65, 95, 0.45), 0 16px 24px rgba(0, 0, 0, 0.28);
}

#game-canvas {
  width: 100%;
  height: 100%;
  display: block;
}

#scene-top-bar {
  position: absolute;
  top: 12px;
  left: 12px;
  right: 244px;
  z-index: 2;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 10px;
  align-items: start;
}

.scene-top-item {
  background: rgba(6, 21, 31, 0.8);
  border: 1px solid rgba(147, 215, 240, 0.3);
  border-radius: 12px;
  padding: 7px 10px;
  color: #d9f3ff;
  font-family: "Space Mono", monospace;
}

#scene-timer-wrap {
  min-width: 132px;
  text-align: center;
  cursor: pointer;
  user-select: none;
}

#scene-timer-wrap:hover {
  border-color: rgba(173, 238, 255, 0.62);
  box-shadow: 0 0 0 1px rgba(173, 238, 255, 0.22) inset;
}

#scene-timer-wrap.active {
  border-color: rgba(82, 255, 208, 0.92);
  background: rgba(8, 44, 42, 0.88);
}

.scene-top-item--progress {
  text-align: center;
  padding: 8px 12px;
}

#scene-progress-title {
  display: block;
  font-size: 0.66rem;
  color: #a9d5e8;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

#scene-progress {
  display: block;
  z-index: 2;
  font-family: "Space Mono", monospace;
  font-size: 1.08rem;
  font-weight: 700;
  color: #d9f3ff;
  letter-spacing: 0.03em;
}

#scene-progress.match {
  color: #b9ffe9;
  text-shadow: 0 0 10px rgba(98, 255, 214, 0.45);
}

#scene-progress-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-top: 4px;
  flex-wrap: wrap;
}

#scene-progress-meta span {
  font-size: 0.78rem;
  white-space: nowrap;
  color: #c7ecff;
}

#scene-solution-wrap {
  position: absolute;
  left: 12px;
  bottom: 12px;
  z-index: 2;
}

#scene-solution-wrap button {
  min-width: 170px;
}

#scene-check-wrap {
  position: absolute;
  left: 50%;
  bottom: 12px;
  transform: translateX(-50%);
  z-index: 2;
}

#scene-check-wrap button {
  min-width: 220px;
  font-size: 0.9rem;
  padding: 11px 14px;
}

#scene-check-wrap button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
  border-color: rgba(180, 199, 209, 0.32);
  box-shadow: none;
  transform: none;
}

#view-controls {
  position: absolute;
  top: 12px;
  right: 12px;
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: 8px 10px;
  min-width: 220px;
  padding: 10px;
  background: rgba(6, 22, 35, 0.8);
  border: 1px solid rgba(147, 215, 240, 0.28);
  border-radius: 12px;
  backdrop-filter: blur(8px);
  z-index: 2;
}

#scene-untangle-wrap {
  position: absolute;
  right: 12px;
  bottom: 12px;
  z-index: 2;
}

#scene-untangle-wrap button {
  min-width: 132px;
}

#view-controls button {
  grid-column: 1 / -1;
  width: 100%;
  padding: 7px 10px;
  font-size: 0.76rem;
}

#view-controls label {
  font-family: "Space Mono", monospace;
  font-size: 0.75rem;
  color: #d8f1ff;
}

#zoom-slider {
  width: 100%;
  accent-color: #2adcb0;
}

#result-pop {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%) scale(0.9);
  min-width: 280px;
  max-width: 86%;
  text-align: center;
  padding: 14px 18px;
  border-radius: 14px;
  border: 1px solid rgba(123, 223, 255, 0.45);
  background: rgba(5, 25, 38, 0.84);
  backdrop-filter: blur(8px);
  box-shadow: 0 16px 26px rgba(0, 0, 0, 0.35);
  font-family: "Space Mono", monospace;
  font-size: 0.92rem;
  color: #e9f8ff;
  opacity: 0;
  pointer-events: none;
}

#result-pop.show {
  animation: resultPop 1500ms ease both;
}

#result-pop .stars {
  display: block;
  font-size: 1.4rem;
  margin: 0 0 6px;
  letter-spacing: 0.12em;
  color: #84ffe0;
}

#result-pop .title {
  display: block;
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 4px;
}

#result-pop .meta {
  display: block;
  color: #cbefff;
  font-size: 0.84rem;
}

@keyframes resultPop {
  0% {
    opacity: 0;
    transform: translate(-50%, -48%) scale(0.88);
  }
  15% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
  }
  80% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
  }
  100% {
    opacity: 0;
    transform: translate(-50%, -54%) scale(0.96);
  }
}

@media (max-width: 980px) {
  body {
    overflow: auto;
  }

  #app {
    grid-template-columns: 1fr;
    grid-template-rows: auto minmax(420px, 1fr);
    height: auto;
    min-height: 100vh;
  }

  #hud {
    max-height: 50vh;
  }

  #scene-wrap {
    min-height: 58vh;
  }

  #view-controls {
    min-width: 180px;
    max-width: calc(100% - 24px);
    top: 94px;
  }

  #scene-top-bar {
    grid-template-columns: 1fr;
    gap: 8px;
    left: 10px;
    right: 10px;
  }

  #scene-progress {
    font-size: 0.95rem;
  }

  #scene-check-wrap {
    left: auto;
    right: 12px;
    transform: none;
    bottom: 56px;
  }

  #scene-check-wrap button {
    min-width: 170px;
  }

  #scene-untangle-wrap {
    bottom: 56px;
  }
}