* {
  box-sizing: border-box;
  font-family:
    system-ui,
    -apple-system,
    Segoe UI,
    Roboto,
    sans-serif;
}

:root {
  --discovery-animation-duration: 2s;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: #0f1117;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  color: #e6e8ee;
  font-size: 1rem;
  line-height: 1.45;
}

header {
  text-align: center;
  padding: 20px 22px;
  font-size: 28px;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: #8ed9ff;
  text-shadow: 0 0 8px rgba(142, 217, 255, 0.2);
  background: linear-gradient(180deg, #1a2231, #141a26);
  border-bottom: 1px solid #2f3a4e;
  box-shadow: 0 6px 16px rgba(4, 10, 20, 0.35);
}

main {
  flex: 1;
  max-width: 1100px;
  margin: auto;
  padding: 20px;
  width: 100%;
}

/* Laboratory */

.laboratory-area {
  margin: 40px 0 12px;
}

.laboratory {
  background: #171a22;
  border-radius: 12px;
  padding: 20px;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.35);
}

/* Element Grid */

.element-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 16px;
}

.element {
  padding: 20px;
  font-size: 20px;
  border-radius: 12px;
  border: 2px solid #4a5366;
  background: #242a36;
  cursor: pointer;
  text-align: center;
  transition:
    background-color 0.15s ease,
    border-color 0.15s ease,
    outline-color 0.15s ease;
  user-select: none;
}

.element.selected {
  background: #334d77;
  border-color: #8bb8ff;
  outline: 3px solid #c9dcff;
}

.element.exhausted-partner {
  opacity: 0.5;
  border-color: #3a4252;
  background: #1d2230;
  cursor: not-allowed;
  pointer-events: none;
}

/* Element Colors */

/* Result */

.reaction-area {
  margin-top: 0;
  margin-bottom: 88px;
}

.panel-title {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #8ed9ff;
  text-shadow: 0 0 10px rgba(142, 217, 255, 0.2);
  margin-bottom: 10px;
}

.reaction-panel {
  background: #171a22;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.3);
  min-height: 160px;
  display: flex;
  flex-direction: column;
  overflow: visible;
}

.reaction-body {
  flex: 1;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  overflow: visible;
}

.reaction-intro,
.hint-line {
  display: block;
  margin-top: 8px;
  color: #f2c879;
  font-weight: 700;
}

.reaction-intro.hidden {
  display: none;
}

.result {
  text-align: center;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.4;
  white-space: pre-line;
  max-width: 100%;
}

/* Discovery Animation */

@keyframes glow {
  0% {
    box-shadow: 0 0 0px gold;
  }
  50% {
    box-shadow: 0 0 20px gold;
  }
  100% {
    box-shadow: 0 0 0px gold;
  }
}

.discovery {
  animation: glow var(--discovery-animation-duration) ease;
}

/* Discovery area */

.discovery-area {
  margin-top: 30px;
}

.progress-row {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  margin-bottom: 12px;
}

.stat-card {
  background: #171a22;
  padding: 16px 18px;
  border-radius: 10px;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.3);
  border: 1px solid #252d3b;
}

.stat-title {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #8ed9ff;
  text-shadow: 0 0 10px rgba(142, 217, 255, 0.2);
  margin-bottom: 8px;
}

.stat-value {
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
  color: #e6e8ee;
}

.stat-subtle {
  margin-top: 8px;
  font-size: 13px;
  color: #8f99ad;
}

.completion-value {
  font-size: 46px;
  font-weight: 800;
  line-height: 1;
  color: #f2c879;
}

.log {
  background: #131822;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.3);
  border: 1px solid #252d3b;
}

.log-title {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: #8ed9ff;
  text-shadow: 0 0 10px rgba(142, 217, 255, 0.2);
  margin-bottom: 10px;
}

.log ul {
  margin: 0;
  padding-left: 18px;
}

.log li {
  margin-bottom: 4px;
  color: #a4adbf;
  font-size: 15px;
}

/* Footer */

footer {
  text-align: center;
  padding: 16px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: #8f99ad;
  background: linear-gradient(180deg, #141a26, #111723);
  border-top: 1px solid #2f3a4e;
  box-shadow: inset 0 1px 0 rgba(142, 217, 255, 0.08);
}

/* Responsive */

@media (max-width: 600px) {
  html {
    font-size: 18px;
  }

  main {
    padding: 14px;
  }

  header {
    font-size: 1.5rem;
    padding: 16px 14px;
  }

  .laboratory-area {
    margin: 20px 0 10px;
  }

  .laboratory,
  .reaction-panel,
  .stat-card,
  .log {
    padding: 14px;
  }

  .element {
    font-size: 1.05rem;
    padding: 14px 12px;
    min-height: 56px;
  }

  .element-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
  }

  .panel-title,
  .log-title,
  .stat-title {
    font-size: 0.76rem;
  }

  .result {
    font-size: 1rem;
  }

  .progress-row {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .completion-value {
    font-size: 2.2rem;
  }

  footer {
    font-size: 0.72rem;
    padding: 12px;
  }
}

@media (max-width: 900px) {
  .progress-row {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}