* { margin: 0; padding: 0; box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
:root {
  --bg: #ffffff; --bg-card: #fafafa; --bg-soft: #f2f2f2;
  --text-1: #171717; --text-2: #525252; --text-3: #737373; --text-4: #a3a3a3;
  --line: rgba(0,0,0,.08); --line-2: rgba(0,0,0,.15);
  --accent: #171717;
}
body {
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", -apple-system, BlinkMacSystemFont, sans-serif;
  color: var(--text-1);
  background: var(--bg);
  min-height: 100vh;
}
.nav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.85);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--line);
  padding: calc(12px + env(safe-area-inset-top)) 18px 12px;
  display: flex; align-items: center; gap: 14px;
}
.nav .back {
  display: flex; align-items: center; gap: 4px;
  padding: 6px 10px; border-radius: 8px;
  font-size: 13px; color: var(--text-2);
  text-decoration: none; transition: all .2s;
}
.nav .back:hover { background: var(--bg-soft); color: var(--text-1); }
.nav .back svg { width: 14px; height: 14px; }
.nav .brand { flex: 1; font-size: 14px; letter-spacing: 1.5px; font-weight: 600; }
.nav .brand span { color: var(--text-3); font-weight: 400; margin-left: 6px; font-size: 12px; }

.wrap { max-width: 720px; margin: 0 auto; padding: 0 18px 60px; }
.hero { padding: 36px 0 24px; text-align: center; }
.hero h1 { font-size: 26px; font-weight: 800; letter-spacing: 1px; }
.hero p { margin-top: 8px; font-size: 13px; color: var(--text-3); }

#dropzone {
  border: 2px dashed var(--line-2);
  border-radius: 16px;
  background: var(--bg-card);
  padding: 40px 20px;
  text-align: center;
  cursor: pointer;
  transition: border-color .2s, background .2s;
  outline: none;
}
#dropzone:hover, #dropzone:focus, #dropzone.drag {
  border-color: var(--text-1);
  background: var(--bg-soft);
}
.dz-icon { font-size: 36px; }
.dz-main { margin-top: 10px; font-size: 15px; }
.dz-main b { color: var(--text-1); }
.dz-sub { margin-top: 6px; font-size: 12px; color: var(--text-4); }

#workspace { margin-top: 28px; }
#workspace h2 { font-size: 16px; font-weight: 700; margin: 26px 0 12px; letter-spacing: .5px; }

.origin-card {
  display: flex; gap: 16px; align-items: flex-start;
  background: var(--bg-card); border: 1px solid var(--line);
  border-radius: 14px; padding: 14px;
}
.origin-img { flex: 1; min-width: 0; display: flex; justify-content: center; }
.origin-img img { max-width: 100%; max-height: 240px; border-radius: 8px; object-fit: contain; }
.origin-meta { width: 150px; flex-shrink: 0; font-size: 13px; color: var(--text-2); padding-top: 4px; }
.origin-name { display: flex; align-items: center; gap: 8px; word-break: break-all; }
.badge {
  background: var(--text-1); color: #fff; font-size: 11px;
  padding: 2px 7px; border-radius: 999px; letter-spacing: 1px;
}
.dim { color: var(--text-4); font-size: 12px; margin-top: 6px; }

.chips { display: flex; flex-wrap: wrap; gap: 10px; }
.chips .chip {
  border: 1px solid var(--line-2);
  background: var(--bg-card);
  border-radius: 999px;
  padding: 9px 18px;
  font-size: 14px;
  color: var(--text-1);
  cursor: pointer;
  transition: all .15s;
}
.chips .chip:hover { border-color: var(--text-1); background: var(--bg-soft); }
.chips .chip:active { transform: scale(.97); }
.chips .chip:disabled { opacity: .4; cursor: not-allowed; }

.speed-card {
  background: var(--bg-card); border: 1px solid var(--line);
  border-radius: 14px; padding: 16px;
  margin-top: 26px;
}
.speed-head { display: flex; justify-content: space-between; align-items: center; }
.speed-card h2 { margin: 0 !important; }
.speed-val { font-size: 18px; font-weight: 700; font-variant-numeric: tabular-nums; }
#speed-slider { width: 100%; margin: 14px 0 4px; accent-color: var(--text-1); }
.check { display: flex; align-items: flex-start; gap: 8px; font-size: 12px; color: var(--text-3); margin: 8px 0 14px; cursor: pointer; }
.check input { margin-top: 1px; accent-color: var(--text-1); }

.btn {
  border: 1px solid var(--line-2);
  background: var(--bg);
  border-radius: 10px;
  padding: 10px 22px;
  font-size: 14px;
  color: var(--text-1);
  cursor: pointer;
  transition: all .15s;
}
.btn:hover { background: var(--bg-soft); }
.btn:disabled { opacity: .4; cursor: not-allowed; }
.btn.primary { background: var(--text-1); color: #fff; border-color: var(--text-1); font-weight: 600; }
.btn.primary:hover { background: #000; }

#result-box {
  background: var(--bg-card); border: 1px solid var(--line);
  border-radius: 14px; padding: 14px;
  display: flex; justify-content: center;
}
#result-box img { max-width: 100%; max-height: 320px; border-radius: 8px; object-fit: contain; }
#result-meta { margin-top: 8px; }
.warn {
  margin-top: 10px; padding: 10px 12px;
  background: #fff8e6; border: 1px solid #f0d489;
  border-radius: 10px; color: #8a6d1a; font-size: 12px;
  white-space: pre-wrap;
}
#download { margin-top: 14px; width: 100%; padding: 13px; font-size: 15px; }

.hint {
  margin-top: 18px; text-align: center;
  font-size: 13px; color: var(--text-3);
}
.hint.err { color: #c0392b; }
.hide { display: none !important; }

@media (max-width: 620px) {
  .nav { padding: calc(6px + env(safe-area-inset-top)) 14px 6px; gap: 8px; }
  .nav .back { padding: 4px 6px; font-size: 12px; }
  .nav .back svg { width: 12px; height: 12px; }
  .nav .brand { font-size: 13px; letter-spacing: 1px; }
  .nav .brand span { font-size: 11px; margin-left: 4px; }
  .hero { padding: 18px 0 18px; }
  .hero h1 { font-size: 22px; }
}
@media (max-width: 360px) {
  .nav .brand span { display: none; }
}