:root {
  --bg: #f6f8fb;
  --card: #ffffff;
  --text: #16181d;
  --muted: #6b7280;
  --accent: #2f6bed;
  --accent-soft: #e8effd;
  --border: #e4e7ec;
  --ok: #16a34a;
  --radius: 14px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Pretendard", "Malgun Gothic", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.container { max-width: 860px; margin: 0 auto; padding: 0 20px; }

header { background: var(--card); border-bottom: 1px solid var(--border); }
.nav { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.logo { font-size: 1.25rem; font-weight: 800; color: var(--text); text-decoration: none; }
.logo span { color: var(--accent); }
.nav-links { display: flex; gap: 18px; }
.nav-links a { color: var(--muted); text-decoration: none; font-size: 0.92rem; }
.nav-links a:hover { color: var(--text); }

.tool-page { padding: 44px 0 56px; }
.tool-page > h1 { font-size: 1.7rem; text-align: center; margin-bottom: 8px; }
.tool-page > .sub { text-align: center; color: var(--muted); margin-bottom: 32px; }
.badge {
  display: block;
  width: fit-content;
  margin: 0 auto 14px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: 999px;
}

.dropzone {
  display: block;
  background: var(--card);
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 56px 20px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}
.dropzone:hover, .dropzone.drag { border-color: var(--accent); background: var(--accent-soft); }
.dropzone .big { font-size: 1.1rem; font-weight: 700; margin-bottom: 6px; }
.dropzone .small { color: var(--muted); font-size: 0.9rem; }
.dropzone input { display: none; }

.opt-row { display: flex; align-items: center; gap: 10px; margin-top: 20px; justify-content: center; flex-wrap: wrap; }
.opt-row select, .opt-row input[type="number"] {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 9px 12px;
  font-size: 0.95rem;
  background: var(--card);
  color: var(--text);
}
.opt-row input[type="number"] { width: 120px; }
.opt-row input[type="range"] { width: 170px; accent-color: var(--accent); }
.opt-note { color: var(--muted); font-size: 0.85rem; width: 100%; text-align: center; }

.file-list { margin-top: 20px; display: flex; flex-direction: column; gap: 8px; }
.file-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 16px;
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.92rem;
}
.file-item .name { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.file-item .meta { color: var(--muted); font-size: 0.85rem; flex-shrink: 0; }
.file-item .saved { color: var(--ok); font-weight: 700; font-size: 0.85rem; flex-shrink: 0; }
.file-item button { border: none; background: none; color: var(--muted); cursor: pointer; font-size: 1rem; padding: 2px 6px; }
.file-item button:hover { color: var(--accent); }
.file-item .dl {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 5px 12px;
  font-size: 0.85rem;
  background: var(--card);
  color: var(--text);
}
.file-item .dl:hover { border-color: var(--accent); color: var(--accent); }

.btn {
  display: inline-block;
  border: none;
  background: var(--accent);
  color: #fff;
  font-size: 1rem;
  font-weight: 700;
  padding: 13px 30px;
  border-radius: 10px;
  cursor: pointer;
  transition: opacity 0.15s;
}
.btn:hover { opacity: 0.9; }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }
.btn.green { background: var(--ok); }
.action-row { margin-top: 24px; text-align: center; display: flex; gap: 10px; justify-content: center; }

.status { margin-top: 14px; text-align: center; font-size: 0.92rem; color: var(--muted); min-height: 1.4em; }
.status.error { color: #dc2626; }

.privacy-note {
  margin-top: 36px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  font-size: 0.9rem;
  color: var(--muted);
}
.privacy-note strong { color: var(--text); }

.pair-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 10px;
  margin-top: 16px;
}
.pair-grid a {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 11px 8px;
  text-align: center;
  text-decoration: none;
  color: var(--text);
  font-size: 0.9rem;
  font-weight: 600;
  transition: border-color 0.15s, color 0.15s;
}
.pair-grid a:hover { border-color: var(--accent); color: var(--accent); }
.section-title { font-size: 1.2rem; font-weight: 800; margin: 40px 0 4px; }

.faq { padding: 24px 0 64px; }
.faq h2 { font-size: 1.3rem; margin: 24px 0 18px; }
.faq details {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 18px;
  margin-bottom: 10px;
}
.faq summary { font-weight: 700; cursor: pointer; font-size: 0.95rem; }
.faq details p { margin-top: 10px; color: var(--muted); font-size: 0.92rem; }

footer { border-top: 1px solid var(--border); padding: 28px 0; text-align: center; color: var(--muted); font-size: 0.85rem; }

@media (max-width: 600px) {
  .tool-page > h1 { font-size: 1.35rem; }
}