:root {
  --bg: #f4f5f7;
  --surface: #ffffff;
  --border: #e6e8ec;
  --border-strong: #cfd4dc;
  --text: #16181d;
  --text-secondary: #475467;
  --muted: #6b7280;
  --danger: #b42318;
  --danger-bg: #fef3f2;
  --danger-border: #fda29b;
  --success: #12b76a;
  --focus-ring: #444ce7;
  --mono: "Cascadia Code", Consolas, "Fira Code", monospace;
  --radius: 16px;
  --shadow-card: 0 1px 2px rgba(16, 24, 40, 0.04), 0 8px 24px rgba(16, 24, 40, 0.06);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: linear-gradient(135deg, #e9ebea 0%, #a9c0b1 55%, #1f4d38 100%);
  background-attachment: fixed;
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

.app {
  max-width: 880px;
  margin: 0 auto;
  padding: 44px 24px 56px;
}

.app-header {
  text-align: center;
  margin-bottom: 36px;
}

h1 {
  margin: 0 0 8px;
  font-size: 1.65rem;
  font-weight: 650;
  letter-spacing: -0.02em;
}

.subtitle {
  margin: 0;
  color: rgba(22, 24, 29, 0.65);
  font-size: 0.95rem;
}

/* ---------- Picker layout ---------- */

.picker-section {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: center;
  align-items: stretch;
  margin-bottom: 28px;
}

.canvas-wrapper {
  flex: 0 1 auto;
  display: flex;
  align-items: center;
  justify-content: center;
}

#colorWheel {
  display: block;
  max-width: 100%;
  height: auto;
  border-radius: 50%;
  box-shadow: 0 10px 32px rgba(10, 24, 18, 0.28);
  cursor: crosshair;
}

/* ---------- Info panel ---------- */

.info-panel {
  flex: 1 1 300px;
  max-width: 340px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.swatch {
  width: 100%;
  height: 84px;
  border-radius: 10px;
  background: #eee;
  border: 1px solid rgba(16, 24, 40, 0.08);
  box-shadow: inset 0 1px 2px rgba(16, 24, 40, 0.05);
  transition: background 0.1s ease;
}

.values {
  display: flex;
  flex-direction: column;
}

.value-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 11px 0;
  border-bottom: 1px solid rgba(15, 26, 20, 0.18);
}

.value-row:first-child {
  padding-top: 2px;
}

.value-row:last-child {
  padding-bottom: 2px;
  border-bottom: none;
}

.values h2 {
  margin: 0 0 3px;
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: rgba(15, 26, 20, 0.75);
}

.value-row > div {
  flex: 1 1 auto;
  min-width: 0;
}

.value-input {
  display: block;
  width: 100%;
  margin: 0;
  padding: 4px 6px;
  font-family: var(--mono);
  font-size: 0.92rem;
  color: var(--text);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.value-input:hover {
  border-color: rgba(15, 26, 20, 0.3);
}

.value-input:focus {
  outline: none;
  background: var(--surface);
  border-color: var(--focus-ring);
}

.value-input::placeholder {
  color: rgba(15, 26, 20, 0.55);
}

.value-input.invalid {
  border-color: var(--danger-border);
  background: var(--danger-bg);
}

/* ---------- Buttons ---------- */

.copy-btn {
  flex: 0 0 auto;
  padding: 5px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-secondary);
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

.copy-btn:hover {
  background: #f2f4f7;
  border-color: var(--border-strong);
  color: var(--text);
}

.copy-btn:active {
  transform: translateY(1px);
}

.copy-btn.copied {
  background: var(--success);
  border-color: var(--success);
  color: #fff;
}

.panel-actions {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 4px;
}

#eyedropperBtn {
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid var(--text);
  background: var(--text);
  color: #fff;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease;
}

#eyedropperBtn:hover:not(:disabled) {
  background: #2b3040;
}

#eyedropperBtn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

#resetBtn {
  padding: 10px 16px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--danger);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease;
}

#resetBtn:hover {
  background: var(--danger-bg);
  border-color: var(--danger-border);
}

.copy-btn:focus-visible,
#eyedropperBtn:focus-visible,
#resetBtn:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 2px;
}

/* ---------- Gradient palette ---------- */

.gradient-grid {
  display: grid;
  grid-template-columns: repeat(10, minmax(0, 1fr));
  gap: 6px;
}

.gradient-grid:empty {
  display: none;
}

.gradient-box {
  height: 40px;
  border-radius: 8px;
  border: 1px solid rgba(16, 24, 40, 0.06);
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}

.gradient-box:hover {
  transform: scale(1.06);
  box-shadow: 0 4px 12px rgba(16, 24, 40, 0.16);
}

/* ---------- Small screens ---------- */

@media (max-width: 520px) {
  .app {
    padding: 28px 16px 40px;
  }

  .info-panel {
    max-width: none;
  }
}