:root {
  --ink: #14201f;
  --muted: #4a5c59;
  --paper: #f3f7f5;
  --panel: rgba(255, 255, 255, 0.72);
  --line: rgba(20, 32, 31, 0.12);
  --accent: #0f766e;
  --accent-soft: #99f6e4;
  --shadow: 0 18px 50px rgba(20, 32, 31, 0.12);
  --radius: 18px;
  --font-display: "Fraunces", "Songti TC", serif;
  --font-body: "Sora", "PingFang TC", sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.45;
}

.atmosphere {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(900px 480px at 12% -10%, #c7f9ee 0%, transparent 55%),
    radial-gradient(700px 420px at 95% 10%, #dbeafe 0%, transparent 50%),
    radial-gradient(600px 500px at 50% 110%, #fde68a 0%, transparent 45%),
    linear-gradient(160deg, #f7fbf9 0%, #eef4f2 55%, #e8f0ec 100%);
  animation: drift 14s ease-in-out infinite alternate;
}

@keyframes drift {
  from {
    transform: scale(1) translateY(0);
  }
  to {
    transform: scale(1.04) translateY(-1.2%);
  }
}

.app {
  width: min(720px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 2.5rem 0 3.5rem;
}

.brand-name {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(2.6rem, 8vw, 4.2rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1;
}

.brand h1 {
  margin: 0.55rem 0 0;
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 400;
  color: var(--muted);
}

.stage {
  margin-top: 2rem;
  display: grid;
  gap: 1.25rem;
  grid-template-columns: 1fr;
  padding: 1.25rem;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
  animation: rise 0.55s ease both;
}

@media (min-width: 640px) {
  .stage {
    grid-template-columns: 220px 1fr;
    align-items: stretch;
  }
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.swatch {
  position: relative;
  display: block;
  min-height: 220px;
  border-radius: 14px;
  overflow: hidden;
  cursor: pointer;
  background: var(--accent);
  transition: transform 0.25s ease;
}

.swatch:hover {
  transform: scale(1.015);
}

.swatch input {
  appearance: none;
  border: 0;
  padding: 0;
  width: 140%;
  height: 140%;
  position: absolute;
  inset: -20%;
  cursor: pointer;
  background: transparent;
}

.swatch-hint {
  position: absolute;
  left: 0.9rem;
  bottom: 0.9rem;
  padding: 0.35rem 0.65rem;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.84);
  color: var(--ink);
  font-size: 0.78rem;
  font-weight: 500;
  pointer-events: none;
}

.codes {
  display: grid;
  gap: 0.75rem;
  align-content: center;
}

.code-row {
  display: grid;
  grid-template-columns: 3.2rem 1fr auto;
  gap: 0.65rem;
  align-items: center;
  padding: 0.7rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.65);
}

.code-label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.code-row code {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 0.92rem;
  overflow-wrap: anywhere;
}

.copy-btn,
.text-btn {
  font: inherit;
  cursor: pointer;
  border: 0;
}

.copy-btn {
  padding: 0.4rem 0.7rem;
  border-radius: 999px;
  background: var(--ink);
  color: #fff;
  font-size: 0.78rem;
  font-weight: 500;
  transition: background 0.2s ease, transform 0.2s ease;
}

.copy-btn:hover {
  background: #243836;
  transform: translateY(-1px);
}

.copy-btn:active {
  transform: translateY(0);
}

.related {
  margin-top: 1.5rem;
  animation: rise 0.7s ease 0.08s both;
}

.related-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.8rem;
}

.related h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 500;
}

.text-btn {
  background: transparent;
  color: var(--muted);
  text-decoration: underline;
  text-underline-offset: 0.2em;
  padding: 0;
}

.text-btn:hover {
  color: var(--ink);
}

.palette-strip {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0.55rem;
}

.chip {
  border: 0;
  padding: 0;
  border-radius: 14px;
  min-height: 84px;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: transform 0.2s ease;
}

.chip:hover {
  transform: translateY(-3px);
}

.chip span {
  position: absolute;
  left: 0.55rem;
  bottom: 0.5rem;
  font-size: 0.68rem;
  font-weight: 600;
  color: #fff;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.35);
}

.toast {
  position: fixed;
  left: 50%;
  bottom: 1.4rem;
  transform: translateX(-50%) translateY(8px);
  margin: 0;
  padding: 0.65rem 1rem;
  border-radius: 999px;
  background: var(--ink);
  color: #fff;
  font-size: 0.85rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

@media (max-width: 520px) {
  .palette-strip {
    grid-template-columns: repeat(3, 1fr);
  }

  .code-row {
    grid-template-columns: 3rem 1fr;
  }

  .copy-btn {
    grid-column: 1 / -1;
  }
}