*, *::before, *::after {
      box-sizing: border-box; margin: 0; padding: 0;
      outline: none !important;
      -webkit-tap-highlight-color: transparent !important;
    }
    *:focus, *:focus-visible, *:focus-within {
      outline: none !important; box-shadow: none !important;
    }
    button, input, select, textarea, a {
      font-family: inherit;
      -webkit-tap-highlight-color: rgba(0,0,0,0) !important;
    }

    :root {
      --bg:         #f4f5f7;
      --bg2:        #eaecf0;
      --surface:    #ffffff;
      --surface2:   #f8f9fb;
      --border:     #e1e4ea;
      --border2:    #c8cdd8;
      --accent:     #1a7f5a;
      --accent-h:   #155f44;
      --accent-lt:  #edf7f2;
      --accent-mid: #b2ddc9;
      --success:    #1a7f5a;
      --success-bg: #edf7f2;
      --success-bd: #b2ddc9;
      --danger:     #c0392b;
      --danger-bg:  #fdf3f2;
      --danger-bd:  #f5c6c2;
      --warn:       #b45309;
      --warn-bg:    #fffbeb;
      --warn-bd:    #fde68a;
      --text:       #0f1923;
      --text2:      #2d3a4a;
      --text3:      #5a6a7e;
      --text4:      #9aa5b4;
      --shadow-sm:  0 1px 3px rgba(15,25,35,.07), 0 1px 2px rgba(15,25,35,.04);
      --radius:     10px;
      --radius-sm:  7px;
      --radius-xs:  5px;
    }
    @media (prefers-color-scheme: dark) {
      :root {
        --bg:         #0e1117;
        --bg2:        #161c26;
        --surface:    #1a2130;
        --surface2:   #202838;
        --border:     #2a3445;
        --border2:    #3a4a60;
        --accent:     #2ecc8f;
        --accent-h:   #3ddaa0;
        --accent-lt:  #0d2a1e;
        --accent-mid: #1a5a3a;
        --success:    #2ecc8f;
        --success-bg: #0d2a1e;
        --success-bd: #1a5a3a;
        --danger:     #e55c50;
        --danger-bg:  #2a1210;
        --danger-bd:  #6a2820;
        --warn:       #f59e0b;
        --warn-bg:    #2a1e00;
        --warn-bd:    #6a4c00;
        --text:       #edf0f5;
        --text2:      #bdc8d8;
        --text3:      #7a8fa8;
        --text4:      #3d5068;
        --shadow-sm:  0 1px 3px rgba(0,0,0,.35);
      }
    }

    html { scroll-behavior: smooth; }
    body {
      min-height: 100vh; background: var(--bg); color: var(--text);
      font-family: 'Inter', 'Noto Sans SC', sans-serif;
      font-size: 14px; line-height: 1.6; -webkit-font-smoothing: antialiased;
    }

    /* HEADER — 随页面滚动，不固定 */
    header {
      background: var(--surface); border-bottom: 1px solid var(--border);
      box-shadow: var(--shadow-sm);
    }
    .header-inner {
      max-width: 1040px; margin: 0 auto; padding: 0 24px; height: 58px;
      display: flex; align-items: center; justify-content: space-between;
    }
    .logo { display: flex; align-items: center; gap: 10px; text-decoration: none; }
    .logo-img { width: 32px; height: 32px; border-radius: 7px; object-fit: contain; border: 1px solid var(--border); }
    .logo-name { font-size: 16px; font-weight: 700; color: var(--text); letter-spacing: -.02em; }
    .logo-name span { color: var(--accent); }

    /* 语言切换 */
    .lang-switcher { position: relative; }
    .lang-btn {
      display: flex; align-items: center; gap: 6px;
      padding: 5px 10px; border-radius: var(--radius-xs);
      border: 1px solid var(--border2); background: var(--surface2);
      cursor: pointer; font-size: 13px; color: var(--text2);
      transition: border-color .15s, background .15s;
    }
    .lang-btn:hover { border-color: var(--accent); background: var(--accent-lt); }
    .lang-flag { font-size: 16px; line-height: 1; }
    .lang-dropdown {
      position: absolute; right: 0; top: calc(100% + 6px);
      background: var(--surface); border: 1px solid var(--border);
      border-radius: var(--radius-sm); box-shadow: 0 8px 24px rgba(0,0,0,.12);
      min-width: 170px; z-index: 200;
      max-height: 320px; overflow-y: auto;
      overscroll-behavior: contain;
      -webkit-overflow-scrolling: touch;
    }
    .lang-item {
      display: flex; align-items: center; gap: 8px;
      padding: 9px 14px; cursor: pointer; font-size: 13px; color: var(--text2);
      transition: background .12s;
    }
    .lang-item:hover { background: var(--accent-lt); color: var(--accent); }
    .lang-item.active { background: var(--accent-lt); color: var(--accent); font-weight: 600; }
    .lang-item .lf { font-size: 18px; line-height: 1; }

    /* HERO */
    .hero {
      background: var(--surface); border-bottom: 1px solid var(--border);
      padding: 48px 24px 44px; text-align: center;
    }
    .hero-label {
      display: inline-flex; align-items: center; gap: 6px;
      background: var(--accent-lt); border: 1px solid var(--accent-mid);
      border-radius: 20px; padding: 4px 13px;
      font-size: 12px; font-weight: 500; color: var(--accent); margin-bottom: 18px;
    }
    .hero-dot { width: 6px; height: 6px; border-radius: 50%; background: var(--accent); animation: blink 2s ease-in-out infinite; }
    @keyframes blink { 0%,100%{opacity:1} 50%{opacity:.3} }
    .hero h1 { font-size: clamp(24px, 4.5vw, 40px); font-weight: 700; letter-spacing: -.03em; color: var(--text); line-height: 1.18; margin-bottom: 12px; }
    .hero h1 em { font-style: normal; color: var(--accent); }
    .hero p { font-size: 15px; color: var(--text3); max-width: 460px; margin: 0 auto; }

    /* LAYOUT */
    .wrap { max-width: 1040px; margin: 0 auto; padding: 36px 24px 80px; display: grid; grid-template-columns: 1fr 348px; gap: 22px; align-items: start; }
    @media (max-width: 780px) { .wrap { grid-template-columns: 1fr; } }
    .left { display: flex; flex-direction: column; gap: 18px; }

    /* CARD */
    .card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow-sm); overflow: hidden; }
    .card-head { padding: 13px 18px; border-bottom: 1px solid var(--border); display: flex; align-items: center; gap: 9px; }
    .card-head-ic { width: 26px; height: 26px; border-radius: 6px; background: var(--accent-lt); display: flex; align-items: center; justify-content: center; flex-shrink: 0; }
    .card-head h2 { font-size: 13px; font-weight: 600; color: var(--text2); }
    .card-body { padding: 18px; }

    /* DROPZONE */
    .dz { border: 2px dashed var(--border2); border-radius: var(--radius-sm); padding: 44px 20px; text-align: center; cursor: pointer; transition: border-color .2s, background .2s; position: relative; background: var(--surface2); }
    .dz:hover, .dz.on { border-color: var(--accent); background: var(--accent-lt); }
    .dz input { position: absolute; inset: 0; opacity: 0; cursor: pointer; z-index: 2; }
    .dz-icon { width: 52px; height: 52px; border-radius: 12px; background: var(--surface); border: 1px solid var(--border); box-shadow: var(--shadow-sm); display: flex; align-items: center; justify-content: center; margin: 0 auto 14px; }
    .dz-t { font-size: 14px; font-weight: 600; color: var(--text); margin-bottom: 3px; }
    .dz-t span { color: var(--accent); text-decoration: underline; }
    .dz-s { font-size: 12px; color: var(--text4); }
    .dz-fmts { display: flex; flex-wrap: wrap; justify-content: center; gap: 5px; margin-top: 14px; }
    .fmt-chip { font-size: 11px; font-weight: 500; padding: 2px 8px; border-radius: 20px; background: var(--bg2); border: 1px solid var(--border); color: var(--text3); }

    /* PREVIEW */
    .prev { display: flex; gap: 14px; align-items: flex-start; }
    .prev-img { flex-shrink: 0; width: 88px; height: 88px; border-radius: var(--radius-sm); border: 1px solid var(--border); background: repeating-conic-gradient(var(--bg2) 0% 25%, var(--surface) 0% 50%) 0 0 / 10px 10px; display: flex; align-items: center; justify-content: center; overflow: hidden; }
    .prev-img img { width: 100%; height: 100%; object-fit: contain; }
    .prev-meta { flex: 1; min-width: 0; }
    .prev-name { font-size: 13px; font-weight: 600; color: var(--text); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; margin-bottom: 5px; }
    .prev-row { display: flex; align-items: center; gap: 7px; margin-bottom: 9px; }
    .fmt-badge { font-size: 10px; font-weight: 700; letter-spacing: .04em; padding: 2px 7px; border-radius: 4px; background: var(--accent-lt); border: 1px solid var(--accent-mid); color: var(--accent); }
    .prev-sz { font-size: 12px; color: var(--text4); }
    .btn-rm { display: inline-flex; align-items: center; gap: 4px; padding: 4px 9px; border-radius: var(--radius-xs); border: 1px solid var(--border2); background: transparent; cursor: pointer; color: var(--text3); font-size: 12px; font-weight: 500; transition: all .15s; }
    .btn-rm:hover { border-color: var(--danger-bd); color: var(--danger); background: var(--danger-bg); }

    /* SIZE LIST */
    .s-label { font-size: 11px; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--text4); margin-bottom: 9px; }
    .sz-list { display: flex; flex-direction: column; gap: 4px; margin-bottom: 14px; }
    .sz-item { display: flex; align-items: center; gap: 11px; padding: 9px 13px; border: 1.5px solid var(--border); border-radius: var(--radius-xs); cursor: pointer; background: var(--surface2); transition: all .14s; user-select: none; }
    .sz-item:hover:not(.on) { border-color: var(--border2); background: var(--bg2); }
    .sz-item.on { border-color: var(--accent); background: var(--accent-lt); }
    .sz-radio { width: 15px; height: 15px; border-radius: 50%; border: 2px solid var(--border2); display: flex; align-items: center; justify-content: center; flex-shrink: 0; transition: border-color .14s; }
    .sz-item.on .sz-radio { border-color: var(--accent); }
    .sz-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); }
    .sz-px { font-size: 13px; font-weight: 600; color: var(--text); }
    .sz-item.on .sz-px { color: var(--accent); }

    /* QUALITY */
    .q-tabs { display: flex; gap: 5px; margin-bottom: 18px; }
    .q-tab { flex: 1; padding: 7px 5px; border: 1.5px solid var(--border); border-radius: var(--radius-xs); background: var(--surface2); cursor: pointer; font-size: 12px; font-weight: 500; color: var(--text3); text-align: center; transition: all .14s; }
    .q-tab:hover:not(.on) { border-color: var(--border2); color: var(--text2); }
    .q-tab.on { border-color: var(--accent); background: var(--accent-lt); color: var(--accent); font-weight: 600; }

    /* CONVERT BTN */
    .btn-go { width: 100%; padding: 12px; background: var(--accent); color: #fff; border: none; border-radius: var(--radius-sm); font-size: 14px; font-weight: 600; cursor: pointer; display: flex; align-items: center; justify-content: center; gap: 8px; box-shadow: 0 2px 8px rgba(26,127,90,.30); transition: background .15s, transform .1s; }
    .btn-go:hover:not(:disabled) { background: var(--accent-h); }
    .btn-go:active:not(:disabled) { transform: scale(.99); }
    .btn-go:disabled { background: var(--bg2); color: var(--text4); box-shadow: none; cursor: not-allowed; }

    /* PROGRESS */
    .prog { margin-top: 13px; }
    .prog-track { height: 4px; background: var(--bg2); border-radius: 99px; overflow: hidden; }
    .prog-fill { height: 100%; background: var(--accent); border-radius: 99px; transition: width .3s ease; }
    .prog-txt { font-size: 12px; color: var(--text4); margin-top: 5px; }

    /* ERROR */
    .err-box { margin-top: 12px; padding: 10px 14px; background: var(--danger-bg); border: 1px solid var(--danger-bd); border-radius: var(--radius-xs); font-size: 12px; color: var(--danger); line-height: 1.6; }
    .err-box details { margin-top: 8px; }
    .err-box summary { cursor: pointer; font-size: 11px; opacity: .8; user-select: none; }
    .err-box pre { margin-top: 6px; font-size: 11px; white-space: pre-wrap; word-break: break-all; opacity: .85; background: rgba(0,0,0,.05); padding: 6px 8px; border-radius: 4px; }

    /* RESULT */
    .res-card { margin-top: 13px; background: var(--success-bg); border: 1.5px solid var(--success-bd); border-radius: var(--radius-sm); overflow: hidden; }
    .res-head { padding: 9px 14px; border-bottom: 1px solid var(--success-bd); display: flex; align-items: center; gap: 7px; }
    .res-head span { font-size: 12px; font-weight: 600; color: var(--success); }
    .res-body { padding: 12px 14px; }
    .res-info { font-size: 12px; color: var(--text3); margin-bottom: 10px; display: flex; align-items: center; gap: 7px; }
    .res-tag { font-size: 11px; font-weight: 600; padding: 2px 8px; border-radius: 4px; background: var(--success-bg); border: 1px solid var(--success-bd); color: var(--success); }
    .btn-dl { width: 100%; padding: 10px; background: var(--success); color: #fff; border: none; border-radius: var(--radius-xs); font-size: 13px; font-weight: 600; cursor: pointer; display: flex; align-items: center; justify-content: center; gap: 7px; transition: opacity .14s, transform .1s; box-shadow: 0 2px 6px rgba(26,127,90,.25); }
    .btn-dl:hover { opacity: .88; }
    .btn-dl:active { transform: scale(.99); }

    .div { height: 1px; background: var(--border); margin: 14px 0; }

    /* RIGHT */
    .right { display: flex; flex-direction: column; gap: 14px; }
    .steps-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow-sm); padding: 16px 18px; }
    .steps-card h3 { font-size: 13px; font-weight: 600; color: var(--text); margin-bottom: 13px; }
    .step { display: flex; gap: 11px; align-items: flex-start; margin-bottom: 10px; }
    .step:last-child { margin-bottom: 0; }
    .step-n { width: 20px; height: 20px; border-radius: 50%; flex-shrink: 0; background: var(--accent-lt); border: 1.5px solid var(--accent-mid); display: flex; align-items: center; justify-content: center; font-size: 10px; font-weight: 700; color: var(--accent); }
    .step-t { font-size: 12px; color: var(--text3); padding-top: 1px; line-height: 1.6; }
    .info-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow-sm); padding: 14px 16px; display: flex; gap: 12px; align-items: flex-start; }
    .ic-icon { width: 34px; height: 34px; border-radius: 8px; flex-shrink: 0; display: flex; align-items: center; justify-content: center; }
    .ic-icon.g { background: #f0fdf4; }
    .ic-icon.b { background: #eff6ff; }
    .ic-icon.y { background: #fffbeb; }
    @media (prefers-color-scheme: dark) {
      .ic-icon.g { background: #0a2a15; }
      .ic-icon.b { background: #0f1e3d; }
      .ic-icon.y { background: #2d2000; }
    }
    .info-card h3 { font-size: 13px; font-weight: 600; color: var(--text); margin-bottom: 3px; }
    .info-card p  { font-size: 12px; color: var(--text3); line-height: 1.65; }

    footer { border-top: 1px solid var(--border); padding: 18px 24px; text-align: center; font-size: 12px; color: var(--text4); }

    @keyframes spin { to { transform: rotate(360deg); } }
    .spin { animation: spin .7s linear infinite; }