:root {
  --bg: #0f1720;
  --panel: #12202b;
  --panel-soft: rgba(10, 19, 27, 0.82);
  --card: rgba(232, 242, 231, 0.08);
  --card-border: rgba(227, 244, 221, 0.12);
  --text: #eef6ef;
  --muted: #b1c2b8;
  --accent: #efc14a;
  --accent-strong: #f6d768;
  --success: #8fe388;
  --danger: #ff8c7b;
  --grid: rgba(255, 255, 255, 0.06);
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.28);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "IBM Plex Sans", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(239, 193, 74, 0.08), transparent 28%),
    radial-gradient(circle at bottom right, rgba(61, 115, 73, 0.2), transparent 34%),
    linear-gradient(145deg, #0d141b, #182731 52%, #10181e);
}

.app-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(0, 1.8fr) minmax(320px, 0.9fr);
  gap: 24px;
  padding: 24px;
}

.simulation-panel,
.control-panel {
  min-width: 0;
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 18px;
}

.eyebrow {
  margin: 0 0 6px;
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
}

h1,
h2 {
  margin: 0;
  font-family: "Space Grotesk", sans-serif;
  font-weight: 700;
}

h1 {
  font-size: clamp(1.9rem, 2.4vw, 2.7rem);
}

h2 {
  font-size: 1.05rem;
  margin-bottom: 14px;
}

.status-chip {
  padding: 10px 14px;
  border-radius: 999px;
  background: rgba(239, 193, 74, 0.12);
  border: 1px solid rgba(239, 193, 74, 0.2);
  color: var(--accent-strong);
  font-size: 0.92rem;
  white-space: nowrap;
}

.canvas-frame {
  position: relative;
  height: clamp(420px, 72vh, 820px);
  min-height: 420px;
  border-radius: 28px;
  padding: 18px;
  background: linear-gradient(180deg, rgba(8, 15, 21, 0.95), rgba(12, 29, 25, 0.95));
  border: 1px solid rgba(255, 255, 255, 0.06);
  box-shadow: var(--shadow);
}

canvas {
  width: 100%;
  height: 100%;
  display: block;
  border-radius: 20px;
  background:
    linear-gradient(rgba(245, 255, 245, 0.028) 1px, transparent 1px),
    linear-gradient(90deg, rgba(245, 255, 245, 0.028) 1px, transparent 1px),
    radial-gradient(circle at 30% 20%, rgba(255, 247, 187, 0.05), transparent 24%),
    linear-gradient(180deg, #133129, #0d1f1d 55%, #11261f);
  background-size: 42px 42px, 42px 42px, auto, auto;
}

.control-panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.card {
  padding: 18px;
  border-radius: 22px;
  background: var(--card);
  border: 1px solid var(--card-border);
  box-shadow: var(--shadow);
  backdrop-filter: blur(14px);
}

.button-stack {
  display: grid;
  gap: 10px;
}

button {
  appearance: none;
  border: 0;
  border-radius: 16px;
  padding: 14px 16px;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  transition: transform 140ms ease, opacity 140ms ease, background 140ms ease;
}

button:hover:enabled {
  transform: translateY(-1px);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

.primary-button {
  color: #182123;
  background: linear-gradient(135deg, var(--accent-strong), #f4b54d);
}

.secondary-button {
  color: var(--text);
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.toggle-row,
.constant-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.toggle-row + .toggle-row,
.constant-row + .constant-row {
  margin-top: 12px;
}

.toggle-row input {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
}

.hint {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.45;
}

.input-group {
  display: grid;
  gap: 8px;
}

.input-group + .input-group {
  margin-top: 14px;
}

.input-group span,
.constant-row span {
  color: var(--muted);
  font-size: 0.93rem;
}

input[type="number"] {
  width: 100%;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 14px;
  padding: 13px 14px;
  color: var(--text);
  background: rgba(4, 11, 15, 0.45);
  font: inherit;
}

input[type="number"]:focus {
  outline: 2px solid rgba(239, 193, 74, 0.3);
  border-color: rgba(239, 193, 74, 0.45);
}

.feedback-card p {
  margin: 0;
  line-height: 1.55;
  color: var(--text);
}

.feedback-card.success {
  border-color: rgba(143, 227, 136, 0.42);
  background: rgba(143, 227, 136, 0.11);
}

.feedback-card.error {
  border-color: rgba(255, 140, 123, 0.44);
  background: rgba(255, 140, 123, 0.11);
}

@media (max-width: 1100px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .canvas-frame {
    height: clamp(360px, 58vh, 620px);
    min-height: 360px;
  }
}

@media (max-width: 640px) {
  .app-shell {
    padding: 14px;
    gap: 14px;
  }

  .canvas-frame {
    height: clamp(300px, 46vh, 420px);
    min-height: 300px;
    padding: 12px;
    border-radius: 22px;
  }

  .panel-header {
    flex-direction: column;
  }

  .status-chip {
    white-space: normal;
  }
}