@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@300;400;500;700;900&display=swap');
*{margin:0;padding:0;box-sizing:border-box}
:root{
  --bg:#08111e;--surface:#131c30;--surface-alt:#1c2741;--border:#1f2e4a;
  --text:#d4dceb;--text-dim:#7d8ba2;
  --accent:#3aaeff;--accent-glow:rgba(58,174,255,0.32);
  --success:#3ddca3;--success-glow:rgba(61,220,163,0.25);--danger:#ff6b8a;
}
body{font-family:'Noto Sans JP',sans-serif;background:var(--bg);color:var(--text);align-items:center;overflow-x:hidden}
body::before{content:'';position:fixed;top:-40%;left:-20%;width:80vw;height:80vw;background:radial-gradient(circle,rgba(58,174,255,0.07) 0%,transparent 70%);pointer-events:none;z-index:0}
body::after{content:'';position:fixed;bottom:-30%;right:-10%;width:60vw;height:60vw;background:radial-gradient(circle,rgba(108,199,255,0.05) 0%,transparent 70%);pointer-events:none;z-index:0}
.tool-hero{position:relative;z-index:1;text-align:center;padding:60px 20px 30px}
.tool-hero h1{font-size:clamp(1.8rem,5vw,2.8rem);font-weight:900;letter-spacing:-0.02em;background:linear-gradient(135deg,var(--text) 0%,var(--accent) 100%);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;color:transparent}
.tool-hero h1 span{-webkit-text-fill-color:var(--accent);color:var(--accent)}
.tool-hero p{margin-top:12px;color:var(--text-dim);font-size:0.95rem;font-weight:300;line-height:1.7}
.container{position:relative;z-index:1;width:100%;max-width:640px;padding:0 20px 80px}
.drop-zone{border:2px dashed var(--border);border-radius:16px;padding:50px 30px;text-align:center;cursor:pointer;transition:all 0.3s ease;background:var(--surface);position:relative;overflow:hidden}
.drop-zone::before{content:'';position:absolute;inset:0;background:linear-gradient(135deg,var(--accent-glow) 0%,transparent 50%);opacity:0;transition:opacity 0.3s}
.drop-zone:hover,.drop-zone.dragover{border-color:var(--accent)}
.drop-zone:hover::before,.drop-zone.dragover::before{opacity:1}
.drop-zone-icon{font-size:3rem;margin-bottom:16px;display:block;opacity:0.7}
.drop-zone-text{font-size:1rem;color:var(--text-dim);line-height:1.8}
.drop-zone-text strong{color:var(--accent);font-weight:500}
.drop-zone-hint{margin-top:10px;font-size:0.78rem;color:var(--text-dim);opacity:0.7}
#fileInput{display:none}
.file-info{display:none;background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:20px 24px;margin-top:20px;animation:fadeUp .4s ease}
.file-info.show{display:flex;gap:16px;align-items:center}
.file-thumbnail{width:120px;min-width:120px;height:68px;border-radius:8px;object-fit:cover;background:var(--surface-alt);display:none}
.file-thumbnail.show{display:block}
.file-meta{flex:1;min-width:0}
.file-name{font-weight:500;font-size:0.95rem;margin-bottom:6px;word-break:break-all}
.file-size{color:var(--text-dim);font-size:0.85rem}
.settings{display:none;background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:24px;margin-top:16px;animation:fadeUp .4s ease}
.settings.show{display:block}
.settings-title{font-size:0.85rem;font-weight:500;color:var(--text-dim);text-transform:uppercase;letter-spacing:0.08em;margin-bottom:18px}
.setting-group{margin-bottom:20px}.setting-group:last-child{margin-bottom:0}
.setting-label{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px;font-size:0.9rem}
.setting-value{color:var(--accent);font-weight:500;font-variant-numeric:tabular-nums}
.range-legend{display:flex;justify-content:space-between;font-size:0.72rem;color:var(--text-dim);margin-top:4px}
input[type="range"]{-webkit-appearance:none;appearance:none;width:100%;height:6px;border-radius:3px;background:var(--surface-alt);outline:none;cursor:pointer}
input[type="range"]::-webkit-slider-thumb{-webkit-appearance:none;appearance:none;width:20px;height:20px;border-radius:50%;background:var(--accent);box-shadow:0 0 12px var(--accent-glow);cursor:pointer;transition:transform .15s}
input[type="range"]::-webkit-slider-thumb:hover{transform:scale(1.2)}
.option-row{display:flex;gap:8px;flex-wrap:wrap}
.option-btn{padding:8px 16px;border:1px solid var(--border);border-radius:8px;background:var(--surface-alt);color:var(--text-dim);font-size:0.82rem;font-family:inherit;cursor:pointer;transition:all .2s}
.option-btn:hover{border-color:var(--accent);color:var(--text)}
.option-btn.active{border-color:var(--accent);background:var(--accent);color:#fff}
.option-btn[disabled]{opacity:0.4;cursor:not-allowed;pointer-events:none}
.setting-group.hidden{display:none}
.hint{margin-top:8px;font-size:0.74rem;color:var(--text-dim);line-height:1.5}
.convert-btn{display:none;width:100%;margin-top:20px;padding:18px;border:none;border-radius:12px;background:linear-gradient(135deg,var(--accent),#8b7cf7);color:#fff;font-family:inherit;font-size:1.05rem;font-weight:700;letter-spacing:0.02em;cursor:pointer;transition:all .3s;position:relative;overflow:hidden}
.convert-btn.show{display:block;animation:fadeUp .4s ease}
.convert-btn:hover{transform:translateY(-2px);box-shadow:0 8px 30px var(--accent-glow)}
.convert-btn:active{transform:translateY(0)}
.convert-btn:disabled{opacity:0.5;cursor:not-allowed;transform:none!important;box-shadow:none!important}
.progress-area{display:none;margin-top:20px;animation:fadeUp .4s ease}
.progress-area.show{display:block}
.progress-bar-bg{width:100%;height:8px;background:var(--surface-alt);border-radius:4px;overflow:hidden}
.progress-bar{height:100%;width:0%;background:linear-gradient(90deg,var(--accent),var(--success));border-radius:4px;transition:width .3s}
.progress-text{display:flex;justify-content:space-between;margin-top:10px;font-size:0.85rem;color:var(--text-dim)}
.progress-status{display:flex;align-items:center;gap:8px}
.spinner{width:14px;height:14px;border:2px solid var(--border);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}
.result{display:none;background:var(--surface);border:1px solid var(--success);border-radius:12px;padding:28px 24px;margin-top:20px;text-align:center;animation:fadeUp .5s ease}
.result.show{display:block}
.result-icon{font-size:2.5rem;margin-bottom:12px}
.result-title{font-size:1.1rem;font-weight:700;margin-bottom:16px;color:var(--success)}
.result-preview{max-width:100%;max-height:280px;border-radius:8px;background:var(--surface-alt);margin:0 auto 20px;display:block}
.result-preview:not([src]){display:none}
.result-stats{display:flex;justify-content:center;gap:32px;margin-bottom:20px;flex-wrap:wrap}
.stat{text-align:center}
.stat-label{font-size:0.75rem;color:var(--text-dim);text-transform:uppercase;letter-spacing:0.06em;margin-bottom:4px}
.stat-value{font-size:1.3rem;font-weight:700;font-variant-numeric:tabular-nums}
.download-btn{display:inline-block;padding:14px 40px;border:none;border-radius:10px;background:var(--success);color:var(--bg);font-family:inherit;font-size:1rem;font-weight:700;cursor:pointer;transition:all .3s;text-decoration:none}
.download-btn:hover{transform:translateY(-2px);box-shadow:0 8px 30px var(--success-glow)}
.reset-btn{display:inline-block;margin-top:14px;padding:10px 24px;border:1px solid var(--border);border-radius:8px;background:transparent;color:var(--text-dim);font-family:inherit;font-size:0.85rem;cursor:pointer;transition:all .2s}
.reset-btn:hover{border-color:var(--text-dim);color:var(--text)}
.error-msg{display:none;background:rgba(255,107,129,0.1);border:1px solid var(--danger);border-radius:12px;padding:18px 24px;margin-top:20px;color:var(--danger);font-size:0.9rem;text-align:center}
.error-msg.show{display:block;animation:fadeUp .4s ease}
.features{display:grid;grid-template-columns:repeat(auto-fit,minmax(160px,1fr));gap:12px;margin-top:40px}
.feature{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:18px 16px;text-align:center;transition:border-color .3s}
.feature:hover{border-color:var(--accent)}
.feature-icon{font-size:1.4rem;margin-bottom:8px;display:block}
.feature-text{font-size:0.78rem;color:var(--text-dim);line-height:1.5}
@keyframes fadeUp{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}
@keyframes spin{to{transform:rotate(360deg)}}
@media(max-width:480px){.tool-hero{padding:40px 16px 20px}.drop-zone{padding:36px 20px}.result-stats{gap:20px}}