:root {
  --bg-1: #f0e7d9;
  --bg-2: #c7d6e8;
  --panel: rgba(253, 248, 240, 0.88);
  --ink: #101010;
  --accent: #174a72;
  --accent-strong: #0d3556;
  --line: #d6cbbb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Gill Sans", "Avenir Next", "Trebuchet MS", sans-serif;
  color: #202124;
  background:
    radial-gradient(circle at 18% 16%, rgba(255, 255, 255, 0.42), transparent 42%),
    radial-gradient(circle at 86% 78%, rgba(255, 255, 255, 0.38), transparent 45%),
    linear-gradient(135deg, var(--bg-1), var(--bg-2));
}

.app {
  width: min(1180px, 96vw);
  margin: 2rem auto;
  display: grid;
  gap: 1rem;
  grid-template-columns: 320px 1fr;
}

.controls {
  border: 1px solid rgba(20, 20, 20, 0.1);
  border-radius: 16px;
  padding: 1rem;
  background: var(--panel);
  backdrop-filter: blur(2px);
  box-shadow: 0 10px 30px rgba(19, 28, 40, 0.12);
}

h1 {
  margin: 0 0 0.8rem;
  letter-spacing: 0.02em;
  font-size: 1.35rem;
}

.control {
  display: grid;
  gap: 0.45rem;
  margin-bottom: 0.85rem;
}

.control > span {
  font-size: 0.92rem;
  font-weight: 600;
}

select,
input[type="range"],
button,
input[type="color"],
input[type="text"],
input[type="password"],
textarea {
  font: inherit;
}

select,
input[type="text"],
input[type="password"] {
  border: 1px solid rgba(23, 74, 114, 0.2);
  border-radius: 10px;
  padding: 0.45rem 0.5rem;
  background: #fefcf8;
}

.tool-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.45rem;
}

.tool {
  border-radius: 10px;
  border: 1px solid #c3ccd6;
  background: #fafcfe;
  padding: 0.45rem 0.55rem;
  cursor: pointer;
}

.tool.active {
  border-color: var(--accent);
  background: #dce9f5;
}

.color-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.swatch {
  border: 2px solid rgba(30, 30, 30, 0.18);
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--swatch);
  cursor: pointer;
}

.swatch.active {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

#customColor {
  width: 38px;
  height: 28px;
  border: 1px solid rgba(30, 30, 30, 0.25);
  border-radius: 7px;
  background: #fff;
  cursor: pointer;
}

input[type="range"] {
  width: 100%;
}

.action-row {
  display: grid;
  gap: 0.5rem;
}

.action-row button {
  border: 1px solid transparent;
  border-radius: 10px;
  padding: 0.55rem;
  cursor: pointer;
}

.action-row .secondary {
  background: #ece8e0;
  border-color: #d5cdc1;
}

.action-row .primary {
  background: var(--accent);
  color: #fff;
}

.action-row .primary:hover {
  background: var(--accent-strong);
}

.latex-panel {
  margin-top: 1rem;
  padding-top: 0.8rem;
  border-top: 1px dashed rgba(23, 74, 114, 0.26);
}

.latex-panel h2 {
  margin: 0 0 0.75rem;
  font-size: 1rem;
}

.latex-output-wrap {
  margin-bottom: 0.35rem;
}

.latex-output {
  width: 100%;
  min-height: 100px;
  resize: vertical;
  border: 1px solid rgba(23, 74, 114, 0.2);
  border-radius: 10px;
  padding: 0.55rem;
  background: #fefcf8;
  line-height: 1.35;
}

.hint {
  margin: 0;
  color: #4b5966;
  font-size: 0.8rem;
}

#statusMessage {
  min-height: 1.3em;
  margin: 0.55rem 0 0;
  font-size: 0.9rem;
  color: #173a5a;
}

.canvas-wrap {
  display: flex;
  align-items: stretch;
}

.board {
  width: 100%;
  min-height: 66vh;
  aspect-ratio: 4 / 3;
  border-radius: 16px;
  overflow: hidden;
  border: 1px solid rgba(14, 14, 14, 0.16);
  box-shadow: 0 14px 34px rgba(16, 22, 32, 0.2);
  position: relative;
  background: #fefcf8;
}

canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

#drawCanvas {
  touch-action: none;
  cursor: crosshair;
}

@media (max-width: 980px) {
  .app {
    grid-template-columns: 1fr;
  }

  .board {
    min-height: 52vh;
  }
}