:root {
  --bg: #F7F5F0;
  --surface: #FFFFFF;
  --ink: #1A1814;
  --muted: #8A887F;
  --line: #E0DDD6;
  --accent: #3D6B5E;
  --accent-dark: #2F564B;
  --accent-mid: #5A9A8A;
  --accent-soft: #EBF2EF;
  --danger: #B4503C;
  --radius: 16px;
  --shadow: 0 1px 2px rgba(43, 43, 40, .04), 0 8px 24px rgba(43, 43, 40, .06);
  --font: "Apple SD Gothic Neo", "Noto Sans KR", "Pretendard", system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; }

/* HTML hidden 속성이 명시적 display(flex/grid)보다 항상 우선하도록 */
[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  -webkit-font-smoothing: antialiased;
  line-height: 1.5;
}

a { color: var(--accent); }

.app {
  max-width: 920px;
  margin: 0 auto;
  padding: 32px 20px 64px;
}

/* ── Top bar (언어 선택) ── */
.topbar { display: flex; justify-content: flex-end; margin-bottom: 6px; }
.lang-wrap { display: inline-flex; align-items: center; }
#langSelect {
  font-family: inherit;
  font-size: 13.5px;
  color: var(--ink);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 9px;
  padding: 7px 28px 7px 12px;
  cursor: pointer;
  -webkit-appearance: none;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath d='M2 4l4 4 4-4' fill='none' stroke='%238A887F' stroke-width='1.6' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
}
#langSelect:hover { border-color: var(--accent); }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* ── Header ── */
.masthead {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 28px;
}
.brand { display: flex; align-items: center; gap: 14px; }
.brand-mark { display: inline-flex; }
.brand-text h1 { margin: 0; font-size: 26px; letter-spacing: -.5px; }
.brand-text p { margin: 2px 0 0; color: var(--muted); font-size: 14px; }
.badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.badges li {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 6px 12px;
  font-size: 12.5px;
  color: var(--muted);
}

/* ── Buttons ── */
.btn {
  font-family: inherit;
  font-size: 15px;
  font-weight: 600;
  border-radius: 11px;
  padding: 11px 18px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: background .15s, border-color .15s, transform .05s, opacity .15s;
}
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover:not(:disabled) { background: var(--accent-dark); }
.btn-ghost { background: var(--surface); color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }
.btn-sm { padding: 7px 13px; font-size: 13px; }

/* ── Mode tabs ── */
.mode-tabs {
  display: flex;
  gap: 8px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 13px;
  padding: 5px;
  margin-bottom: 16px;
}
.mode-tab {
  flex: 1;
  font-family: inherit;
  font-size: 15px;
  font-weight: 600;
  color: var(--muted);
  background: transparent;
  border: none;
  border-radius: 9px;
  padding: 11px 10px;
  cursor: pointer;
  transition: background .15s, color .15s;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}
.mode-tab > span:not(.mode-sub) { white-space: nowrap; }
.mode-tab .mode-sub { font-size: 12px; font-weight: 500; opacity: .8; }
.mode-tab:hover { color: var(--ink); }
.mode-tab.is-active { background: var(--accent); color: #fff; }
.mode-tab.is-active .mode-sub { opacity: .85; }

/* ── Color (chroma) controls ── */
.color-controls {
  margin-top: 18px;
  padding: 16px;
  background: var(--accent-soft);
  border-radius: 12px;
  display: grid;
  gap: 12px;
}
.cc-row { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.cc-label { font-size: 14px; font-weight: 600; color: var(--accent-dark); min-width: 40px; }
.cc-swatch {
  width: 26px; height: 26px;
  border-radius: 7px;
  border: 2px solid #fff;
  box-shadow: 0 0 0 1px var(--line);
  background: #88bbee;
  flex: none;
}
.cc-hint { font-size: 12.5px; color: var(--muted); flex: 1; min-width: 140px; }
.cc-val { font-variant-numeric: tabular-nums; font-size: 13px; color: var(--accent-dark); min-width: 26px; text-align: right; }
#tolerance { flex: 1; accent-color: var(--accent); min-width: 140px; }
.pane-img img.pickable { cursor: crosshair; }

/* ── Dropzone ── */
.dropzone {
  background: var(--surface);
  border: 2px dashed var(--line);
  border-radius: var(--radius);
  padding: 48px 24px;
  text-align: center;
  transition: border-color .15s, background .15s;
  cursor: pointer;
}
.dropzone:hover { border-color: var(--accent); }
.dropzone.drag {
  border-color: var(--accent);
  background: var(--accent-soft);
}
.dropzone-inner { display: flex; flex-direction: column; align-items: center; gap: 14px; }
.dz-icon { opacity: .9; }
.dz-title { margin: 0; font-size: 17px; font-weight: 600; }
.dz-hint { margin: 0; color: var(--muted); font-size: 13px; }

.first-run-note {
  margin: 14px 2px 0;
  font-size: 13px;
  color: var(--muted);
  text-align: center;
}

/* ── Stage ── */
.stage {
  margin-top: 26px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px;
}
.stage-head {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  align-items: center;
  justify-content: space-between;
}
.stage-name { margin: 0; font-size: 18px; }
.stage-meta { margin: 3px 0 0; color: var(--muted); font-size: 13px; }
.stage-actions { display: flex; gap: 10px; }

/* ── Progress ── */
.progress {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 20px;
  padding: 22px;
  background: var(--accent-soft);
  border-radius: 12px;
}
.spinner {
  width: 30px; height: 30px;
  border: 3px solid rgba(61, 107, 94, .25);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin .8s linear infinite;
  flex: none;
}
@keyframes spin { to { transform: rotate(360deg); } }
.progress-text { flex: 1; min-width: 0; }
#progressLabel { font-size: 14px; font-weight: 600; color: var(--accent-dark); }
.bar {
  margin-top: 8px;
  height: 6px;
  background: rgba(61, 107, 94, .18);
  border-radius: 999px;
  overflow: hidden;
}
.bar-fill {
  height: 100%;
  width: 0%;
  background: var(--accent);
  border-radius: 999px;
  transition: width .25s ease;
}

/* ── Compare ── */
.compare {
  margin-top: 20px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
.pane { margin: 0; }
.pane figcaption {
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
  margin-bottom: 8px;
}
.pane-img {
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
  aspect-ratio: 1 / 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #FaFaF8;
}
.pane-img img { max-width: 100%; max-height: 100%; display: block; object-fit: contain; }
.checker {
  background-color: #fff;
  background-image:
    linear-gradient(45deg, #e9e9e9 25%, transparent 25%),
    linear-gradient(-45deg, #e9e9e9 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #e9e9e9 75%),
    linear-gradient(-45deg, transparent 75%, #e9e9e9 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0;
}
.muted { color: var(--muted); font-weight: 400; }

.error-box {
  margin: 18px 0 0;
  padding: 14px 16px;
  background: #FBEDE9;
  border: 1px solid #EBC9BF;
  border-radius: 12px;
  color: var(--danger);
  font-size: 14px;
}

/* ── History ── */
.history {
  margin-top: 30px;
}
.history-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.history-head h2 { margin: 0; font-size: 17px; }
.history-note { margin: 4px 0 14px; font-size: 13px; color: var(--muted); }
.history-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 12px;
}
.hist-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
  cursor: pointer;
  transition: border-color .15s, transform .05s;
}
.hist-card:hover { border-color: var(--accent); }
.hist-card:active { transform: translateY(1px); }
.hist-thumb {
  aspect-ratio: 1 / 1;
  background-color: #fff;
  background-image:
    linear-gradient(45deg, #ededed 25%, transparent 25%),
    linear-gradient(-45deg, #ededed 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #ededed 75%),
    linear-gradient(-45deg, transparent 75%, #ededed 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0;
  display: flex; align-items: center; justify-content: center;
}
.hist-thumb img { max-width: 100%; max-height: 100%; object-fit: contain; }
.hist-meta {
  padding: 8px 10px;
  font-size: 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  border-top: 1px solid var(--line);
}
.hist-name { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; color: var(--muted); }
.hist-dl {
  flex: none;
  border: none;
  background: var(--accent-soft);
  color: var(--accent-dark);
  border-radius: 7px;
  padding: 4px 8px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
}
.hist-dl:hover { background: var(--accent); color: #fff; }

/* ── About (SEO 본문) ── */
.about {
  margin-top: 40px;
  padding: 22px 24px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.about h2 { margin: 0 0 10px; font-size: 17px; }
.about p { margin: 0; font-size: 14px; color: #55534C; line-height: 1.7; }

/* ── FAQ ── */
.faq { margin-top: 20px; }
.faq h2 { margin: 0 0 12px; font-size: 17px; }
.faq details {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 2px 16px;
  margin-bottom: 10px;
}
.faq details[open] { border-color: var(--accent); }
.faq summary {
  cursor: pointer;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  padding: 13px 0;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  color: var(--accent);
  font-size: 20px;
  font-weight: 400;
  flex: none;
}
.faq details[open] summary::after { content: "−"; }
.faq details p {
  margin: 0 0 14px;
  font-size: 14px;
  color: #55534C;
  line-height: 1.7;
}

/* ── Footer ── */
.footer {
  margin-top: 32px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  text-align: center;
  font-size: 12.5px;
  color: var(--muted);
}
.footer p { margin: 6px 0; }
.footer .lic { font-size: 13px; color: #55534C; }
.footer .lic strong { color: var(--accent-dark); }
.footer .privacy { font-size: 12px; }
.footer .credit { font-size: 12.5px; }
.footer .hub { margin-top: 12px; }
.footer .hub a {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  text-decoration: none;
  padding: 7px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
}
.footer .hub a:hover { border-color: var(--accent); background: var(--accent-soft); }
.footer a { color: var(--muted); text-decoration: underline; }
.footer a:hover { color: var(--accent); }

/* ── Mobile ── */
@media (max-width: 600px) {
  .app { padding: 22px 14px 48px; }
  .masthead { justify-content: center; text-align: center; flex-direction: column; }
  .compare { grid-template-columns: 1fr; }
  .stage-actions { width: 100%; }
  .stage-actions .btn { flex: 1; }
  .dropzone { padding: 36px 16px; }
  .mode-tab { font-size: 14px; padding: 10px 8px; }
  .mode-tab .mode-sub { display: none; }
}