:root {
  color-scheme: dark;
  --bg: #07141a;
  --panel: #10232d;
  --panel-border: #224454;
  --text: #d7eef5;
  --muted: #90aeb8;
  --accent: #58f0dc;
  --accent-fill: rgba(88, 240, 220, 0.22);
  --accent-handle: #9bf7eb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top, rgba(45, 118, 145, 0.18), transparent 30%),
    linear-gradient(180deg, #050b0f, var(--bg));
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
}

.app-shell {
  min-height: 100vh;
  padding: 24px;
  display: grid;
  grid-template-rows: auto 1fr;
  gap: 20px;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  background: rgba(16, 35, 45, 0.92);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.28);
}

.tool-button {
  appearance: none;
  border: 1px solid #34657b;
  border-radius: 6px;
  background: #15303d;
  color: var(--text);
  padding: 10px 16px;
  font-size: 14px;
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease, transform 0.15s ease;
}

.tool-button:hover {
  background: #1a3a49;
  border-color: #4e89a3;
}

.tool-button.active {
  background: rgba(88, 240, 220, 0.14);
  border-color: var(--accent);
  color: #d9fffb;
}

.tool-button:active {
  transform: translateY(1px);
}

.hint {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  margin-left: auto;
  color: var(--muted);
  font-size: 13px;
}

.workspace {
  min-height: 0;
  display: grid;
  place-items: center;
}

.viewer {
  position: relative;
  width: min(100%, 1180px);
  aspect-ratio: 16 / 9;
  border: 1px solid var(--panel-border);
  border-radius: 8px;
  overflow: hidden;
  background:
    linear-gradient(180deg, rgba(17, 40, 49, 0.9), rgba(7, 20, 26, 0.96));
  box-shadow: 0 24px 48px rgba(0, 0, 0, 0.32);
}

.viewer img,
.viewer canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.viewer img {
  object-fit: contain;
  background: #000;
  user-select: none;
  -webkit-user-drag: none;
}

.viewer canvas {
  cursor: crosshair;
}

.viewer.frame-mode canvas {
  cursor: crosshair;
}

.viewer.line-mode canvas {
  cursor: crosshair;
}

@media (max-width: 720px) {
  .app-shell {
    padding: 16px;
  }

  .toolbar {
    padding: 12px;
  }

  .hint {
    margin-left: 0;
  }
}