/* === Reset & Base === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0f172a;
  --bg-card: #1e293b;
  --bg-input: #0f172a;
  --border: #334155;
  --border-focus: #3b82f6;
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --secondary: #475569;
  --secondary-hover: #64748b;
  --radius: 12px;
  --radius-sm: 8px;
  --radius-xs: 6px;
  --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', 'JetBrains Mono', monospace;
  --font-ui: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

html { font-size: 15px; }
body {
  font-family: var(--font-ui);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.6;
}

.container { max-width: 960px; margin: 0 auto; padding: 0 20px; }

/* === Header === */
.header {
  border-bottom: 1px solid var(--border);
  padding: 20px 0;
  background: linear-gradient(135deg, #0f172a 0%, #1a2a4a 100%);
}
.header-inner { display: flex; align-items: baseline; gap: 16px; flex-wrap: wrap; }
.logo { font-size: 1.5rem; font-weight: 700; color: var(--text); letter-spacing: -0.5px; }
.tagline { color: var(--text-muted); font-size: 0.9rem; }

/* === Tabs === */
.tabs {
  display: flex; gap: 2px; margin-top: 24px;
  background: var(--bg-card); border-radius: var(--radius) var(--radius) 0 0; padding: 4px;
  overflow-x: auto;
}
.tab {
  display: flex; align-items: center; gap: 6px;
  padding: 10px 18px; border: none; background: transparent; color: var(--text-muted);
  font-size: 0.9rem; font-family: var(--font-ui); cursor: pointer; border-radius: var(--radius-xs);
  white-space: nowrap; transition: all 0.15s;
}
.tab:hover { color: var(--text); background: rgba(255,255,255,0.05); }
.tab.active { color: #fff; background: var(--primary); box-shadow: 0 2px 8px rgba(59,130,246,0.3); }
.tab:focus-visible { outline: 2px solid var(--primary); outline-offset: -2px; }
.tab-icon { font-size: 1.1rem; }

/* === Tab Panels === */
.tab-panel { display: none; }
.tab-panel.active { display: block; }

.panel-body {
  background: var(--bg-card); padding: 24px; border-radius: 0 0 var(--radius) var(--radius);
  border: 1px solid var(--border); border-top: none;
  display: flex; flex-direction: column; gap: 20px;
}

/* === Color Preview === */
.preview-section { text-align: center; }
.color-preview {
  width: 100%; height: 120px; border-radius: var(--radius-sm);
  background: #3b82f6; display: flex; align-items: center; justify-content: center;
  border: 1px solid rgba(255,255,255,0.1); transition: background 0.2s;
}
.hex-display {
  font-family: var(--font-mono); font-size: 1.5rem; font-weight: 700;
  text-shadow: 0 1px 4px rgba(0,0,0,0.5);
  background: rgba(0,0,0,0.3); padding: 6px 16px; border-radius: var(--radius-xs);
  backdrop-filter: blur(4px);
  letter-spacing: 0.5px;
}

.color-picker-row { margin-top: 12px; display: flex; justify-content: center; }
.color-picker-wrap {
  display: inline-flex; align-items: center; gap: 8px;
  cursor: pointer; padding: 8px 16px; background: var(--bg-input);
  border: 1px solid var(--border); border-radius: var(--radius-xs);
  transition: border-color 0.15s;
}
.color-picker-wrap:hover { border-color: var(--primary); }
.color-picker-wrap input[type="color"] {
  width: 36px; height: 36px; border: none; padding: 0; cursor: pointer;
  border-radius: 4px; background: none;
}
.color-picker-wrap input[type="color"]::-webkit-color-swatch-wrapper { padding: 0; }
.color-picker-wrap input[type="color"]::-webkit-color-swatch { border: 1px solid var(--border); border-radius: 4px; }
.picker-label { font-size: 0.85rem; color: var(--text-muted); }

/* === Values Section === */
.values-section { display: grid; grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); gap: 10px; }
.value-card { background: var(--bg-input); border: 1px solid var(--border); border-radius: var(--radius-xs); padding: 10px 12px; }
.value-label { font-size: 0.7rem; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.8px; margin-bottom: 4px; font-weight: 600; }
.value-row { display: flex; gap: 4px; }
.value-input {
  flex: 1; padding: 4px 8px; background: transparent; color: var(--text);
  border: 1px solid transparent; border-radius: 4px; font-size: 0.82rem;
  outline: none; transition: border-color 0.15s;
}
.value-input:focus { border-color: var(--border-focus); background: rgba(59,130,246,0.05); }
.mono { font-family: var(--font-mono); }

/* === Info Section === */
.info-section { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 600px) { .info-section { grid-template-columns: 1fr; } }
.info-section h3 { font-size: 0.82rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.5px; margin-bottom: 8px; }

.similar-colors { display: flex; flex-wrap: wrap; gap: 6px; }
.sim-color { width: 40px; height: 40px; border-radius: var(--radius-xs); border: 1px solid var(--border); cursor: pointer; transition: transform 0.15s; }
.sim-color:hover { transform: scale(1.15); }

.color-info-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 4px; }
.info-item { display: flex; justify-content: space-between; padding: 4px 8px; background: var(--bg-input); border-radius: 4px; font-size: 0.78rem; }
.info-item span:first-child { color: var(--text-dim); }
.info-item span:last-child { color: var(--text); font-family: var(--font-mono); }

/* === Palette === */
.palette-controls { display: flex; gap: 16px; flex-wrap: wrap; align-items: flex-end; }
.control-row { display: flex; flex-direction: column; gap: 4px; }
.control-row label { font-size: 0.78rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.5px; font-weight: 600; }
.control-row select, .control-row input[type="color"] { padding: 6px 10px; background: var(--bg-input); color: var(--text); border: 1px solid var(--border); border-radius: var(--radius-xs); font-size: 0.82rem; }
.control-row select { cursor: pointer; min-width: 140px; }
.control-row select:focus { outline: none; border-color: var(--border-focus); }
.control-row input[type="color"] { width: 40px; height: 36px; padding: 2px; cursor: pointer; }
.control-row input[type="color"]::-webkit-color-swatch-wrapper { padding: 0; }
.control-row input[type="color"]::-webkit-color-swatch { border: 1px solid var(--border); border-radius: 4px; }

.palette-result { display: flex; flex-direction: column; gap: 6px; min-height: 100px; }
.palette-swatch { display: flex; align-items: center; height: 44px; border-radius: var(--radius-xs); padding: 0 16px; justify-content: space-between; transition: transform 0.1s; }
.palette-swatch:hover { transform: scale(1.02); }
.palette-code { font-family: var(--font-mono); font-size: 0.8rem; text-shadow: 0 1px 2px rgba(0,0,0,0.3); }

.palette-actions { display: flex; gap: 8px; }

/* === Gradient === */
.gradient-preview {
  width: 100%; height: 200px; border-radius: var(--radius-sm);
  background: linear-gradient(135deg, #667eea, #764ba2);
  display: flex; align-items: flex-end; justify-content: center; padding: 16px;
  transition: background 0.3s;
}
.gradient-code-display {
  background: rgba(0,0,0,0.5); backdrop-filter: blur(8px);
  padding: 8px 16px; border-radius: var(--radius-xs);
  font-family: var(--font-mono); font-size: 0.78rem;
  text-align: center; max-width: 100%;
  word-break: break-all;
}

.gradient-controls { display: flex; flex-direction: column; gap: 12px; }
.gradient-colors-row { display: flex; gap: 12px; flex-wrap: wrap; }
.gradient-stop { display: flex; flex-direction: column; gap: 4px; align-items: center; }
.gradient-stop label { font-size: 0.78rem; color: var(--text-muted); }
.gradient-stop input[type="color"] { width: 44px; height: 44px; padding: 2px; border: 1px solid var(--border); border-radius: var(--radius-xs); cursor: pointer; background: none; }
.gradient-stop input[type="color"]::-webkit-color-swatch-wrapper { padding: 0; }
.gradient-stop input[type="color"]::-webkit-color-swatch { border: 1px solid var(--border); border-radius: 4px; }

.gradient-options { display: flex; gap: 16px; flex-wrap: wrap; }
.gradient-actions { display: flex; gap: 8px; flex-wrap: wrap; }

/* === Buttons === */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 16px; border: none; border-radius: var(--radius-xs);
  font-size: 0.82rem; font-family: var(--font-ui); font-weight: 500;
  cursor: pointer; transition: all 0.15s; white-space: nowrap;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-hover); }
.btn-secondary { background: var(--secondary); color: #e2e8f0; }
.btn-secondary:hover { background: var(--secondary-hover); }
.btn-sm { padding: 5px 10px; font-size: 0.78rem; background: var(--secondary); color: #e2e8f0; }
.btn-sm:hover { background: var(--secondary-hover); }

/* === Toast === */
.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%);
  padding: 10px 24px; border-radius: var(--radius); background: var(--bg-card);
  border: 1px solid var(--border); color: var(--text); font-size: 0.85rem;
  box-shadow: 0 4px 20px rgba(0,0,0,0.3); z-index: 100;
  animation: toastIn 0.3s ease;
}
@keyframes toastIn {
  from { opacity: 0; transform: translateX(-50%) translateY(10px); }
  to { opacity: 1; transform: translateX(-50%) translateY(0); }
}

/* === Footer === */
.footer {
  text-align: center; padding: 32px 0; margin-top: 40px;
  border-top: 1px solid var(--border); color: var(--text-dim); font-size: 0.82rem;
}
.footer-small { margin-top: 4px; font-size: 0.75rem; }

.placeholder-text { color: var(--text-dim); font-style: italic; }