:root {
  --ink: #1a1f2a;
  --ink-soft: #3d4657;
  --paper: #f2efe7;
  --paper-strong: #e3e8f2;
  --paper-highlight: #ffffff;
  --accent: #d66b2e;
  --panel: rgba(255, 255, 255, 0.86);
  --panel-section: rgba(244, 240, 230, 0.75);
  --panel-section-border: rgba(26, 31, 42, 0.08);
  --shadow: 0 18px 45px rgba(31, 36, 48, 0.18);
  --button-bg: #ffffff;
  --button-text: #1a1f2a;
  --button-border: rgba(26, 31, 42, 0.2);
  --radius: 18px;
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas,
    "Liberation Mono", "Courier New", monospace;
  --sans: "Space Grotesk", "Helvetica Neue", Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
}

body {
  overflow: hidden;
}

#app[data-theme="dark"] {
  --ink: #f4f6fb;
  --ink-soft: #c8d0df;
  --paper: #0c1018;
  --paper-strong: #151b24;
  --paper-highlight: #1d2532;
  --accent: #e09a4a;
  --panel: rgba(18, 24, 34, 0.9);
  --panel-section: rgba(26, 33, 46, 0.92);
  --panel-section-border: rgba(244, 246, 251, 0.12);
  --shadow: 0 18px 45px rgba(0, 0, 0, 0.45);
  --button-bg: #1d2532;
  --button-text: #f4f6fb;
  --button-border: rgba(244, 246, 251, 0.2);
}

#app {
  position: relative;
  width: 100vw;
  height: 100vh;
  background: radial-gradient(
    circle at top,
    var(--paper-highlight) 0%,
    var(--paper) 40%,
    var(--paper-strong) 100%
  );
}

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

#hud {
  position: absolute;
  top: 28px;
  left: 28px;
  padding: 22px 24px 18px;
  width: min(340px, calc(100vw - 56px));
  background: var(--panel);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}

.title {
  font-size: 20px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--ink-soft);
}

.subtitle {
  font-size: 12px;
  color: var(--ink-soft);
  margin-top: 4px;
  text-transform: uppercase;
  letter-spacing: 0.16em;
}

.howto-row {
  margin-top: 10px;
}

.howto-text {
  margin-top: 8px;
  font-size: 12px;
  color: var(--ink-soft);
  line-height: 1.4;
}

.panel {
  margin-top: 16px;
  padding: 16px;
  background: var(--panel-section);
  border-radius: 14px;
  border: 1px solid var(--panel-section-border);
}

.row {
  display: grid;
  grid-template-columns: 86px 1fr auto;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
  font-size: 13px;
}

.row:last-child {
  margin-bottom: 0;
}

label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--ink-soft);
}

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

button.ghost {
  width: 100%;
  border: 1px solid var(--button-border);
  background: var(--button-bg);
  border-radius: 10px;
  padding: 6px 10px;
  font-family: var(--sans);
  font-size: 13px;
  color: var(--button-text);
  cursor: pointer;
}

button.ghost:hover {
  border-color: color-mix(in srgb, var(--button-border) 40%, var(--button-text));
}

select {
  background: var(--button-bg);
  border: 1px solid var(--button-border);
  border-radius: 10px;
  padding: 6px 10px;
  font-family: var(--sans);
  font-size: 13px;
  color: var(--button-text);
}

input[type="range"] {
  accent-color: var(--accent);
}

.value {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--ink);
}

#status {
  position: absolute;
  right: 32px;
  bottom: 28px;
  padding: 10px 14px;
  background: rgba(26, 31, 42, 0.85);
  color: #ffffff;
  border-radius: 999px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.06em;
}

@media (max-width: 720px) {
  #hud {
    left: 16px;
    top: 16px;
    width: calc(100vw - 32px);
  }

  #status {
    right: 16px;
    bottom: 16px;
  }

  .row {
    grid-template-columns: 1fr;
    gap: 6px;
  }
}