@import url('https://unpkg.com/normalize.css@8.0.1/normalize.css');
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@100;200;300;400;500;600;700;800;900&display=swap');

:root {
  --bg-top: #090909;
  --bg-bottom: #0d181c;
  --text-primary: #f8fafc;
  --text-muted: #cbd5f5;
  --btn-bg: rgba(51, 65, 85, 0.8);
  --btn-bg-hover: rgba(71, 85, 105, 0.8);
  --btn-primary: rgba(9, 79, 93, 0.8);
  --btn-primary-hover: rgba(11, 95, 111, 0.8);
  --btn-merge: rgba(51, 65, 85, 0.8);
  --btn-merge-active: rgba(217, 119, 6, 0.8);
  --btn-merge-locked: rgba(217, 119, 6, 0.5);
  --warn-bg: rgba(9, 9, 12, 0.96);
  --warn-text: #d1d5db;
  --warn-icon: #f87171;
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
  margin: 0;
}

body {
  background: linear-gradient(0deg, var(--bg-bottom) 0%, var(--bg-top) 100%);
  font-family: 'Inter', sans-serif;
  color: var(--text-primary);
  overflow: hidden;
}

#mainContainer {
  position: relative;
  width: 100%;
  height: 100vh;
  overflow: hidden;
}

#canvas {
  width: 100%;
  height: 100%;
  display: block;
  cursor: crosshair;
  background: transparent;
}

.control-bar {
  position: fixed;
  bottom: 8px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 8px;
  z-index: 10;
}

.control-btn {
  width: 40px;
  height: 40px;
  border-radius: 9999px;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  background: var(--btn-bg);
  cursor: pointer;
  backdrop-filter: blur(8px);
  transition: transform 0.2s ease, background 0.2s ease, opacity 0.2s ease;
}

.control-btn svg {
  width: 20px;
  height: 20px;
}

.control-btn:hover {
  transform: scale(1.05);
  background: var(--btn-bg-hover);
}

.control-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.control-btn-primary {
  background: var(--btn-primary);
}

.control-btn-primary:hover:not(:disabled) {
  background: var(--btn-primary-hover);
}

.control-btn-merge {
  background: var(--btn-merge);
}

.control-btn-merge.is-merged {
  background: var(--btn-merge-active);
}

.control-btn-merge.is-locked {
  background: var(--btn-merge-locked);
}

.control-btn[data-tooltip] {
  position: relative;
}

.control-btn[data-tooltip]::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  padding: 6px 10px;
  background: rgba(15, 23, 42, 0.95);
  color: #f1f5f9;
  font-size: 12px;
  font-weight: 500;
  white-space: nowrap;
  border-radius: 6px;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s ease, visibility 0.2s ease;
  pointer-events: none;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.control-btn[data-tooltip]:hover::after {
  opacity: 1;
  visibility: visible;
}

.webgpu-warning {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--warn-bg);
  z-index: 1000;
}

.webgpu-warning.hidden {
  display: none;
}

.webgpu-card {
  max-width: 420px;
  padding: 24px;
  text-align: center;
}

.webgpu-icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 16px;
  color: var(--warn-icon);
}

.webgpu-card h1 {
  margin: 0 0 8px;
  font-size: 22px;
  color: var(--text-primary);
}

.webgpu-card p {
  margin: 0;
  color: var(--warn-text);
  line-height: 1.4;
}

@media (max-width: 640px) {
  .control-bar {
    bottom: 12px;
    gap: 6px;
  }

  .control-btn {
    width: 36px;
    height: 36px;
  }

  .control-btn svg {
    width: 18px;
    height: 18px;
  }
}