:root {
  --flame-color: #ffb347;
  --shadow-color: #120c08;
  --panel-bg: rgba(18, 12, 8, 0.76);
  --panel-border: rgba(255, 244, 232, 0.16);
  --text-main: #fff6ed;
  --text-muted: rgba(255, 246, 237, 0.74);
  --accent: #ffb347;
  --screen-brightness: 0.86;
  --glow-opacity: 0.72;
  --halo-opacity: 0.38;
  --core-scale: 1;
  --glow-size: 62%;
  --drift-x: 0px;
  --drift-y: 0px;
  font-family: "Space Grotesk", "Noto Sans JP", sans-serif;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background: var(--shadow-color);
}

body {
  overflow: hidden;
}

.app {
  position: relative;
  min-height: 100vh;
}

.app.panel-collapsed .control-panel {
  transform: translateX(calc(-100% - 32px));
  opacity: 0;
  pointer-events: none;
}

.app.panel-collapsed .menu-toggle {
  opacity: 1;
  pointer-events: auto;
}

.ambient-layer,
.glow-layer,
.vignette-layer {
  position: fixed;
  inset: 0;
}

.ambient-layer {
  background:
    radial-gradient(circle at calc(50% + var(--drift-x)) calc(54% + var(--drift-y)),
      color-mix(in srgb, var(--flame-color) 35%, transparent) 0%,
      color-mix(in srgb, var(--flame-color) 18%, transparent) 24%,
      transparent 62%),
    linear-gradient(180deg,
      color-mix(in srgb, var(--shadow-color) 72%, #000 28%) 0%,
      var(--shadow-color) 100%);
  filter: brightness(var(--screen-brightness)) saturate(1.08);
  transition: background 140ms linear;
}

.glow-layer {
  background:
    radial-gradient(circle at calc(50% + var(--drift-x)) calc(55% + var(--drift-y)),
      color-mix(in srgb, #fff6d6 88%, var(--flame-color) 12%) 0%,
      color-mix(in srgb, #ffe1a2 72%, var(--flame-color) 28%) 12%,
      color-mix(in srgb, var(--flame-color) 72%, transparent) 32%,
      transparent var(--glow-size));
  opacity: var(--glow-opacity);
  transform: scale(var(--core-scale));
  mix-blend-mode: screen;
}

.glow-layer::after {
  content: "";
  position: absolute;
  inset: -12%;
  background:
    radial-gradient(circle at calc(50% + var(--drift-x)) calc(55% + var(--drift-y)),
      color-mix(in srgb, var(--flame-color) 42%, transparent) 0%,
      transparent 40%);
  opacity: var(--halo-opacity);
  filter: blur(48px);
}

.vignette-layer {
  background:
    radial-gradient(circle at center,
      transparent 30%,
      rgba(0, 0, 0, 0.14) 68%,
      rgba(0, 0, 0, 0.42) 100%);
  pointer-events: none;
}

.menu-toggle {
  position: fixed;
  top: 20px;
  left: 20px;
  z-index: 3;
  display: grid;
  gap: 5px;
  width: 56px;
  height: 56px;
  padding: 0;
  border: 1px solid var(--panel-border);
  border-radius: 18px;
  background: rgba(18, 12, 8, 0.84);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.28);
  opacity: 0;
  pointer-events: none;
  transition: opacity 180ms ease, transform 180ms ease;
  place-items: center;
}

.menu-toggle span,
.panel-icon-button span {
  display: block;
  width: 20px;
  height: 2px;
  border-radius: 999px;
  background: var(--text-main);
}

.control-panel {
  position: relative;
  z-index: 1;
  width: min(92vw, 420px);
  margin: 24px;
  padding: 24px;
  border: 1px solid var(--panel-border);
  border-radius: 24px;
  background: var(--panel-bg);
  color: var(--text-main);
  backdrop-filter: blur(18px);
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.35);
  transition: transform 220ms ease, opacity 220ms ease;
}

.panel-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.panel-icon-button {
  flex: none;
  display: grid;
  gap: 6px;
  min-width: 48px;
  min-height: 48px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-main);
  place-items: center;
}

.panel-icon-button span:first-child {
  transform: translateY(4px);
}

.panel-icon-button span:last-child {
  transform: translateY(-4px);
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 0.84rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 5vw, 3rem);
  line-height: 0.95;
}

.lead,
.note {
  color: var(--text-muted);
  line-height: 1.6;
}

.controls {
  display: grid;
  gap: 16px;
  margin: 24px 0;
}

label {
  display: grid;
  gap: 10px;
}

label span {
  font-weight: 600;
}

input[type="color"] {
  width: 100%;
  height: 52px;
  border: none;
  border-radius: 14px;
  background: transparent;
  cursor: pointer;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}

.actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

button {
  padding: 12px 18px;
  border: 0;
  border-radius: 999px;
  background: var(--accent);
  color: #151515;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.actions button:last-child {
  background: rgba(255, 255, 255, 0.14);
  color: var(--text-main);
}

button:hover {
  filter: brightness(1.05);
}

@media (max-width: 640px) {
  .control-panel {
    margin: 16px;
    padding: 20px;
    width: calc(100vw - 32px);
  }

  .actions button {
    flex: 1 1 140px;
  }
}