:root {
    --bg: #F6F8FA; --surface: #FFFFFF; --ink: #131720; --muted: #5B6675; --faint: #8A94A3;
    --line: #E4E9EF; --accent: #3B5BFD; --accent-ink: #2C46D6; --target: #12B5A6; --danger: #E5484D;
    --shadow: 0 24px 60px -22px rgba(19, 23, 32, .28);
    --sans: "Inter", system-ui, sans-serif; --display: "Space Grotesk", system-ui, sans-serif; --mono: "JetBrains Mono", ui-monospace, monospace;
  }
  * { box-sizing: border-box; }
  html { scroll-behavior: smooth; }
  body { margin: 0; font-family: var(--sans); color: var(--ink); background: var(--bg); line-height: 1.6; -webkit-font-smoothing: antialiased; }
  a { color: inherit; text-decoration: none; }
  .hidden { display: none !important; }
  .wrap { width: 100%; max-width: 1080px; margin: 0 auto; padding: 0 24px; }

  header { position: sticky; top: 0; z-index: 20; background: rgba(246, 248, 250, .82); backdrop-filter: saturate(140%) blur(12px); border-bottom: 1px solid var(--line); }
  .nav { display: flex; align-items: center; justify-content: space-between; height: 68px; }
  .brand { display: flex; align-items: center; gap: 10px; font-family: var(--display); font-weight: 700; font-size: 20px; letter-spacing: -.02em; }
  .brand .mark { width: 26px; height: 26px; border-radius: 8px; background: linear-gradient(135deg, var(--accent), var(--target)); display: grid; place-items: center; color: #fff; font-size: 15px; }
  .nav-links { display: flex; align-items: center; gap: 30px; font-size: 15px; color: var(--muted); font-weight: 500; }
  .nav-links a:hover { color: var(--ink); }
  .btn { font-family: var(--sans); font-weight: 600; font-size: 15px; border: none; cursor: pointer; border-radius: 10px; padding: 10px 18px; background: var(--ink); color: #fff; transition: transform .15s ease, background .15s ease; }
  .btn:hover { background: #000; transform: translateY(-1px); }
  .nav .btn { padding: 9px 16px; }

  .hero { position: relative; text-align: center; padding: 82px 0 40px; overflow: hidden; }
  .hero::before { content: ""; position: absolute; top: -140px; left: 50%; transform: translateX(-50%); width: 720px; height: 460px; background: radial-gradient(closest-side, rgba(59, 91, 253, .18), rgba(18, 181, 166, .10) 55%, transparent 72%); filter: blur(6px); z-index: 0; pointer-events: none; }
  .hero .wrap { position: relative; z-index: 1; }
  .pill-tag { display: inline-flex; align-items: center; gap: 8px; font-size: 13px; font-weight: 500; color: var(--accent-ink); background: rgba(59, 91, 253, .08); border: 1px solid rgba(59, 91, 253, .18); padding: 6px 13px; border-radius: 999px; margin-bottom: 26px; }
  .pill-tag .dot { width: 7px; height: 7px; border-radius: 50%; background: var(--target); }
  h1 { font-family: var(--display); font-weight: 700; font-size: clamp(38px, 6vw, 62px); line-height: 1.04; letter-spacing: -.03em; margin: 0 auto 20px; max-width: 15ch; }
  .lede { font-size: clamp(17px, 2.2vw, 20px); color: var(--muted); max-width: 54ch; margin: 0 auto 40px; }

  .converter { background: var(--surface); border: 1px solid var(--line); border-radius: 22px; box-shadow: var(--shadow); max-width: 560px; margin: 0 auto; padding: 14px; text-align: left; }
  .dropzone { border: 2px dashed #C7D0DC; border-radius: 14px; background: linear-gradient(180deg, #FBFCFE, #F3F6FA); padding: 40px 24px; text-align: center; cursor: pointer; transition: border-color .18s ease, background .18s ease; }
  .dropzone:hover, .dropzone.drag { border-color: var(--accent); background: linear-gradient(180deg, #FBFCFE, #EEF2FF); }
  .drop-icon { width: 46px; height: 46px; margin: 0 auto 14px; border-radius: 12px; background: rgba(59, 91, 253, .10); color: var(--accent); display: grid; place-items: center; }
  .drop-icon svg { animation: bob 2.6s ease-in-out infinite; }
  @keyframes bob { 0%,100%{transform:translateY(0)} 50%{transform:translateY(-4px)} }
  .dropzone strong { display: block; font-size: 17px; font-weight: 600; margin-bottom: 4px; }
  .dropzone span { color: var(--faint); font-size: 14px; }

  .file-card { display: flex; align-items: center; gap: 14px; padding: 14px; border: 1px solid var(--line); border-radius: 14px; background: #FBFCFE; }
  .thumb { width: 52px; height: 52px; border-radius: 10px; object-fit: cover; background: #EEF2F7; border: 1px solid var(--line); flex: none; }
  .thumb-generic { width: 52px; height: 52px; border-radius: 10px; flex: none; background: #EEF2F7; border: 1px solid var(--line); display: grid; place-items: center; color: var(--faint); }
  .file-meta { flex: 1; min-width: 0; }
  .file-name { font-weight: 600; font-size: 15px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
  .file-sub { font-size: 13px; color: var(--faint); }
  .file-x { flex: none; border: none; background: none; cursor: pointer; color: var(--faint); padding: 6px; border-radius: 8px; line-height: 0; }
  .file-x:hover { color: var(--ink); background: #EEF2F7; }

  .convert-row { display: flex; align-items: center; gap: 12px; padding: 16px 8px 8px; }
  .fmt { flex: 1; display: flex; align-items: center; justify-content: space-between; gap: 10px; font-family: var(--mono); font-weight: 600; font-size: 14px; background: #F1F4F8; border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; color: var(--ink); }
  .fmt.source { color: var(--accent-ink); }
  .fmt .lbl-mini { font-family: var(--sans); font-weight: 500; font-size: 11px; color: var(--faint); }
  .fmt-select { flex: 1; font-family: var(--mono); font-weight: 600; font-size: 14px; color: var(--target); background: #F1F4F8; border: 1px solid var(--line); border-radius: 10px; padding: 12px 36px 12px 14px; cursor: pointer; appearance: none; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%238A94A3' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: right 14px center; }
  .fmt-select:hover { border-color: var(--accent); }
  .arrow { flex: none; width: 34px; height: 34px; display: grid; place-items: center; color: #fff; border-radius: 50%; background: linear-gradient(135deg, var(--accent), var(--target)); }
  .convert-cta { display: block; width: 100%; margin-top: 8px; font-family: var(--sans); font-weight: 600; font-size: 16px; color: #fff; background: var(--accent); border: none; border-radius: 12px; padding: 15px; cursor: pointer; transition: background .15s ease, transform .15s ease; text-align: center; }
  .convert-cta:hover { background: var(--accent-ink); transform: translateY(-1px); }
  .convert-cta:disabled { background: #C3CBDA; cursor: not-allowed; transform: none; }
  .convert-cta.secondary { background: transparent; color: var(--muted); border: 1px solid var(--line); }
  .convert-cta.secondary:hover { background: #F1F4F8; color: var(--ink); }

  .note { margin: 12px 4px 4px; font-size: 13.5px; padding: 10px 12px; border-radius: 10px; background: rgba(229, 72, 77, .07); color: #B4282D; border: 1px solid rgba(229, 72, 77, .18); }
  .hint { margin: 12px 4px 4px; font-size: 13px; padding: 10px 12px; border-radius: 10px; background: rgba(59, 91, 253, .07); color: var(--accent-ink); border: 1px solid rgba(59, 91, 253, .16); }
  .result-ok { display: flex; align-items: center; gap: 8px; margin: 14px 4px 12px; font-size: 14px; font-weight: 500; color: var(--target); }

  .assurance { display: flex; justify-content: center; flex-wrap: wrap; gap: 8px 22px; margin-top: 26px; font-size: 14px; color: var(--muted); }
  .assurance span { display: inline-flex; align-items: center; gap: 7px; }
  .assurance svg { color: var(--target); }

  section { padding: 74px 0; }
  .sec-head { margin-bottom: 30px; }
  .sec-head h2 { font-family: var(--display); font-weight: 600; font-size: clamp(24px, 3.4vw, 32px); letter-spacing: -.02em; margin: 0 0 8px; }
  .sec-head p { color: var(--muted); margin: 0; font-size: 16px; max-width: 62ch; }

  .grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
  .conv { display: flex; align-items: center; gap: 9px; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 15px 16px; font-family: var(--mono); font-size: 13.5px; font-weight: 600; color: var(--muted); cursor: pointer; transition: border-color .15s ease, color .15s ease, transform .15s ease; }
  .conv:hover { border-color: var(--accent); color: var(--ink); transform: translateY(-2px); }
  .conv em { font-style: normal; color: var(--faint); font-size: 12px; }

  .why { border-top: 1px solid var(--line); }
  .values { display: grid; grid-template-columns: repeat(3, 1fr); }
  .value { padding: 6px 30px; border-left: 1px solid var(--line); }
  .value:first-child { padding-left: 0; border-left: none; }
  .value:last-child { padding-right: 0; }
  .value .vicon { width: 40px; height: 40px; border-radius: 11px; background: rgba(18, 181, 166, .10); color: var(--target); display: grid; place-items: center; margin-bottom: 16px; }
  .value:nth-child(2) .vicon { background: rgba(59, 91, 253, .10); color: var(--accent); }
  .value h3 { font-family: var(--display); font-weight: 600; font-size: 19px; margin: 0 0 8px; letter-spacing: -.01em; }
  .value p { color: var(--muted); margin: 0; font-size: 15px; }

  footer { border-top: 1px solid var(--line); padding: 40px 0; color: var(--faint); font-size: 14px; }
  .foot { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 16px; }
  .foot-links { display: flex; gap: 24px; }
  .foot-links a:hover { color: var(--ink); }

  @media (max-width: 860px) { .grid { grid-template-columns: repeat(2, 1fr); } .values { grid-template-columns: 1fr; } .value { padding: 26px 0; border-left: none; border-top: 1px solid var(--line); } .value:first-child { padding-top: 0; border-top: none; } }
  @media (max-width: 560px) { .nav-links a:not(.btn) { display: none; } .hero { padding-top: 54px; } .grid { grid-template-columns: 1fr; } }
  @media (prefers-reduced-motion: reduce) { * { animation: none !important; transition: none !important; scroll-behavior: auto; } }
  :focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 6px; }