:root {
  --purple: #4b0aa8;
  --red: #e30613;
  --red-dark: #b30410;
  --bg: #f4f4f7;
  --text: #222;
  --border: #e2e2e8;
  --dark: #1f2430;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Poppins", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
}

button, input, select, textarea {
  font-family: inherit;
}

header {
  text-align: center;
  padding: 40px 16px 24px;
}

header .logo {
  width: min(280px, 70%);
  height: auto;
  display: block;
  margin: 0 auto 10px;
}

header p {
  margin: 0;
  color: #555;
  font-weight: 500;
}

main {
  max-width: 1040px;
  margin: 0 auto;
  padding: 16px 16px 48px;
}

.app-grid {
  display: grid;
  grid-template-columns: 1fr 360px;
  grid-template-areas:
    "preview frames"
    "preview adjust"
    "preview download";
  gap: 24px;
  align-items: start;
}

.preview-card { grid-area: preview; }
.frames-panel { grid-area: frames; }
.adjust-panel { grid-area: adjust; }
#download-btn { grid-area: download; }

@media (max-width: 800px) {
  .app-grid {
    grid-template-columns: 1fr;
    grid-template-areas:
      "frames"
      "preview"
      "adjust"
      "download";
    gap: 16px;
  }
}

.preview-card {
  background: #fff;
  border-radius: 16px;
  padding: 16px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.07);
}

.canvas-wrap {
  position: relative;
  width: 100%;
}

#stage {
  width: 100%;
  height: auto;
  aspect-ratio: 1 / 1;
  border-radius: 12px;
  display: block;
  background: repeating-conic-gradient(#eee 0% 25%, #fff 0% 50%) 50% / 24px 24px;
  touch-action: none;
  cursor: grab;
}

#stage:active {
  cursor: grabbing;
}

.upload-overlay {
  position: absolute;
  left: 50%;
  bottom: 20px;
  transform: translateX(-50%);
  background: var(--dark);
  color: #fff;
  border: none;
  padding: 10px 20px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
}

.upload-overlay:hover {
  filter: brightness(1.15);
}

.upload-overlay.hidden {
  display: none;
}

.panel {
  background: #fff;
  border-radius: 16px;
  padding: 20px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.07);
}

.panel h2 {
  margin: 0 0 4px;
  font-size: 1.05rem;
  font-weight: 700;
}

.panel-sub {
  margin: 0 0 14px;
  font-size: 0.85rem;
  color: #777;
}

.frame-picker {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.frame-option {
  border: 2px solid var(--border);
  border-radius: 12px;
  padding: 6px;
  cursor: pointer;
  background: #fafafa;
  text-align: center;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.frame-option img {
  width: 100%;
  display: block;
  border-radius: 8px;
}

.frame-option span {
  display: block;
  font-size: 0.78rem;
  font-weight: 600;
  margin-top: 6px;
  color: #444;
}

.frame-option.selected {
  border-color: var(--dark);
  box-shadow: 0 0 0 1px var(--dark);
}

.slider-row {
  margin-bottom: 16px;
}

.slider-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 6px;
  color: #444;
}

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

.btn-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 4px;
}

.btn-secondary {
  background: #fff;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 10px 12px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.88rem;
  cursor: pointer;
}

.btn-secondary:hover:not(:disabled) {
  background: #f5f5f5;
}

.btn-primary {
  width: 100%;
  background: var(--red);
  color: #fff;
  border: none;
  padding: 14px 18px;
  border-radius: 12px;
  font-weight: 700;
  font-size: 1rem;
  cursor: pointer;
  box-shadow: 0 2px 10px rgba(0,0,0,0.07);
}

.btn-primary:hover:not(:disabled) {
  filter: brightness(1.08);
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}