html, body { margin: 0; }

.iu-page {
  --bg0: #090b10;
  --bg1: #10141b;
  --surface: rgba(255,255,255,.035);
  --surface-strong: rgba(255,255,255,.06);
  --line: rgba(255,255,255,.12);
  --line-strong: rgba(255,255,255,.19);
  --text: rgba(244,248,252,.94);
  --muted: rgba(214,222,232,.76);
  --faint: rgba(168,180,194,.58);
  --accent: #2379c6;
  --accent-2: #6db0f2;
  --danger: #ffb4ab;
  --danger-bg: rgba(127,29,29,.22);
  --warning: #ffd089;
  --warning-bg: rgba(180,83,9,.12);
  min-height: 100vh;
  color: var(--text);
  font-family: "Avenir Next", "Segoe UI Variable Text", "SF Pro Text", "Noto Sans", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background:
    radial-gradient(1180px 720px at 50% -10%, rgba(35,121,198,.21), transparent 60%),
    radial-gradient(900px 700px at 16% 24%, rgba(95,55,135,.14), transparent 58%),
    radial-gradient(780px 580px at 86% 30%, rgba(41,74,130,.12), transparent 60%),
    linear-gradient(180deg, var(--bg1) 0%, #0b0e14 54%, var(--bg0) 100%);
  font-size: 16px;
  line-height: 1.65;
  letter-spacing: .01em;
  position: relative;
  overflow-x: clip;
  -webkit-font-smoothing: antialiased;
}

.iu-page::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(rgba(255,255,255,.015) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.012) 1px, transparent 1px);
  background-size: 28px 28px;
  mask-image: linear-gradient(180deg, rgba(0,0,0,.28), transparent 72%);
  pointer-events: none;
}

.iu-page > * { position: relative; z-index: 1; }
.iu-page *, .iu-page *::before, .iu-page *::after { box-sizing: border-box; }
.iu-page button, .iu-page input, .iu-page select { font: inherit; }
.iu-page a { color: inherit; text-decoration: none; }
.iu-page img { max-width: 100%; display: block; }
.iu-page button:focus-visible,
.iu-page input:focus-visible,
.iu-page select:focus-visible,
.iu-page a:focus-visible,
.iu-dropzone:focus-visible,
.iu-faq summary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.iu-container { width: min(1080px, calc(100% - 32px)); margin: 0 auto; }
.iu-narrow { width: min(780px, calc(100% - 32px)); margin: 0 auto; }
.iu-mid { width: min(820px, calc(100% - 32px)); margin: 0 auto; }

.iu-header {
  position: sticky;
  top: 0;
  z-index: 80;
  border-bottom: 1px solid rgba(255,255,255,.10);
  background: rgba(10,12,17,.78);
  backdrop-filter: blur(16px);
  box-shadow: 0 12px 40px rgba(0,0,0,.24);
}
.iu-header-inner {
  width: min(1152px, calc(100% - 32px));
  min-height: 68px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 22px;
}
.iu-brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -.02em;
  white-space: nowrap;
}
.iu-brand img { width: 32px; height: 32px; border-radius: 999px; }
.iu-brand em { color: var(--faint); font-style: normal; font-weight: 650; }
.iu-desktop-nav { display: flex; align-items: center; gap: 20px; margin-left: auto; }
.iu-desktop-nav a { color: var(--muted); font-size: 13px; font-weight: 560; }
.iu-desktop-nav a:hover { color: var(--accent); }
.iu-header-cta {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  justify-content: center;
  padding: 0 15px;
  border: 1px solid rgba(35,121,198,.4);
  border-radius: 999px;
  background: rgba(35,121,198,.11);
  color: #6db0f2 !important;
  font-size: 13px;
  font-weight: 700;
}
.iu-header-cta:hover { background: rgba(35,121,198,.17); }
.iu-mobile-toggle { display: none; width: 42px; height: 42px; border: 0; border-radius: 9px; background: transparent; color: var(--text); cursor: pointer; }
.iu-mobile-menu { display: none; }

.iu-intro { padding: 44px 0 30px; text-align: center; }
.iu-intro h1,
.iu-section-heading h2,
.iu-card h3,
.iu-value-grid h3,
.iu-how-grid h3,
.iu-footer h3 {
  font-family: "Iowan Old Style", "Palatino Linotype", "Book Antiqua", "Songti SC", "STSong", serif;
}
.iu-intro h1 {
  margin: 0 0 12px;
  color: #6db0f2;
  font-size: clamp(2.05rem, 4vw, 3.25rem);
  line-height: 1.08;
  letter-spacing: -.045em;
}
.iu-intro p { max-width: 700px; margin: 0 auto; color: var(--muted); font-size: 16px; line-height: 1.7; }
.iu-privacy-row { margin-top: 18px; display: flex; justify-content: center; gap: 8px; flex-wrap: wrap; }
.iu-privacy-row span {
  padding: 6px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255,255,255,.025);
  color: var(--faint);
  font-size: 11px;
}

.iu-tool-section { padding: 30px 0 72px; }
.iu-section-heading { max-width: 760px; margin: 0 auto 28px; text-align: center; }
.iu-section-heading-left { max-width: none; margin-left: 0; text-align: left; }
.iu-section-heading h2 { margin: 9px 0 8px; color: var(--text); font-size: 29px; line-height: 1.2; letter-spacing: -.018em; }
.iu-section-heading p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.7; }
.iu-section-heading p + p { margin-top: 9px; }

.iu-tool-grid { display: grid; grid-template-columns: minmax(0,.88fr) minmax(0,1.12fr); gap: 20px; align-items: stretch; }
.iu-card {
  min-width: 0;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: linear-gradient(180deg, rgba(255,255,255,.045), rgba(255,255,255,.025));
  box-shadow: 0 22px 60px rgba(0,0,0,.32);
}
.iu-card-heading { display: flex; align-items: flex-start; gap: 12px; margin-bottom: 18px; }
.iu-step {
  width: 30px;
  height: 30px;
  flex: 0 0 30px;
  border: 1px solid rgba(35,121,198,.45);
  border-radius: 999px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  font-size: 12px;
  font-weight: 800;
}
.iu-card h3 { margin: 0; color: var(--text); font-size: 20px; line-height: 1.25; }
.iu-card-heading p { margin: 2px 0 0; color: var(--faint); font-size: 12px; }

.iu-dropzone {
  min-height: 310px;
  padding: 20px;
  border: 1.5px dashed rgba(35,121,198,.42);
  border-radius: 15px;
  background: rgba(8,10,14,.48);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  text-align: center;
  cursor: pointer;
  transition: border-color .16s ease, background .16s ease, transform .16s ease;
}
.iu-dropzone:hover, .iu-dropzone.is-dragging { border-color: var(--accent); background: rgba(35,121,198,.075); }
.iu-dropzone.is-dragging { transform: translateY(-1px); }
.iu-dropzone input { position: absolute; width: 1px; height: 1px; opacity: 0; overflow: hidden; pointer-events: none; }
.iu-upload-mark { width: 56px; height: 56px; display: grid; place-items: center; border-radius: 999px; background: rgba(35,121,198,.1); color: var(--accent); font-size: 29px; line-height: 1; }
.iu-dropzone strong { max-width: 100%; color: var(--text); font-size: 14px; overflow-wrap: anywhere; }
.iu-dropzone > span { color: var(--faint); font-size: 12px; }
.iu-dropzone small { color: rgba(168,180,194,.48); font-size: 11px; }
.iu-source-preview-frame {
  width: 100%;
  height: 190px;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 11px;
  background:
    linear-gradient(45deg, rgba(255,255,255,.035) 25%, transparent 25%, transparent 75%, rgba(255,255,255,.035) 75%),
    linear-gradient(45deg, rgba(255,255,255,.035) 25%, transparent 25%, transparent 75%, rgba(255,255,255,.035) 75%);
  background-size: 18px 18px;
  background-position: 0 0, 9px 9px;
}
.iu-source-preview-frame img { width: 100%; height: 100%; object-fit: contain; }
.iu-local-note { margin: 14px 0 0; color: var(--faint); font-size: 11px; line-height: 1.6; }

.iu-settings-card { display: flex; flex-direction: column; }
.iu-field { display: block; min-width: 0; }
.iu-field > span, .iu-control-label > span { display: block; margin-bottom: 6px; color: var(--muted); font-size: 12px; font-weight: 700; }
.iu-field input, .iu-field select {
  width: 100%;
  min-height: 44px;
  padding: 8px 12px;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  outline: 0;
  background: rgba(8,10,14,.78);
  color: var(--text);
}
.iu-field input:focus, .iu-field select:focus { border-color: var(--accent); box-shadow: 0 0 0 2px rgba(35,121,198,.12); }
.iu-control-block { margin-top: 18px; }
.iu-control-block-first { margin-top: 0; }
.iu-control-label { display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.iu-control-label small { color: var(--faint); font-size: 11px; text-align: right; }
.iu-factor-grid { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 7px; }
.iu-factor-grid button,
.iu-print-preset-grid button {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: rgba(255,255,255,.025);
  color: var(--muted);
  text-align: left;
  cursor: pointer;
}
.iu-factor-grid button { min-height: 66px; padding: 9px 10px; }
.iu-factor-grid button:hover:not(:disabled), .iu-print-preset-grid button:hover:not(:disabled) { border-color: rgba(35,121,198,.65); color: var(--text); }
.iu-factor-grid button.is-active, .iu-print-preset-grid button.is-active { border-color: var(--accent); background: rgba(35,121,198,.13); color: var(--accent-2); }
.iu-factor-grid strong, .iu-factor-grid small, .iu-factor-grid em,
.iu-print-preset-grid strong, .iu-print-preset-grid small, .iu-print-preset-grid em { display: block; }
.iu-factor-grid strong { font-size: 14px; line-height: 1.2; }
.iu-factor-grid small { margin-top: 5px; color: var(--faint); font-size: 9px; line-height: 1.35; overflow-wrap: anywhere; }
.iu-factor-grid em, .iu-print-preset-grid em { margin-top: 5px; color: var(--warning); font-size: 9px; line-height: 1.3; font-style: normal; }
.iu-print-preset-grid { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 7px; }
.iu-print-preset-grid button { min-height: 68px; padding: 8px 9px; }
.iu-print-preset-grid strong { font-size: 11px; line-height: 1.3; }
.iu-print-preset-grid small { margin-top: 4px; color: var(--faint); font-size: 9px; line-height: 1.35; }
.iu-factor-grid button:disabled, .iu-print-preset-grid button:disabled, .iu-actions button:disabled { cursor: not-allowed; opacity: .42; }
.iu-control-help { margin: 8px 0 0; color: var(--faint); font-size: 10px; line-height: 1.5; }

.iu-sharpen-field { display: block; margin-top: 18px; }
.iu-sharpen-field > span { display: flex; align-items: center; justify-content: space-between; gap: 12px; color: var(--muted); font-size: 12px; }
.iu-sharpen-field b { font-weight: 700; }
.iu-sharpen-field output { min-width: 32px; color: var(--accent-2); font-weight: 800; text-align: right; }
.iu-sharpen-field input { width: 100%; margin: 8px 0 3px; accent-color: var(--accent); cursor: pointer; }
.iu-sharpen-field small { display: block; color: var(--faint); font-size: 10px; line-height: 1.5; }
.iu-format-field { margin-top: 18px; }
.iu-format-field > small { display: block; margin-top: 6px; color: var(--faint); font-size: 11px; line-height: 1.5; }

.iu-summary {
  margin-top: 18px;
  display: grid;
  grid-template-columns: repeat(2,minmax(0,1fr));
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(8,10,14,.35);
}
.iu-summary > div { min-width: 0; padding: 12px; border-bottom: 1px solid var(--line); }
.iu-summary > div:nth-child(odd) { border-right: 1px solid var(--line); }
.iu-summary > div:nth-last-child(-n+2) { border-bottom: 0; }
.iu-summary span { display: block; color: var(--faint); font-size: 10px; text-transform: uppercase; letter-spacing: .07em; }
.iu-summary strong { display: block; margin-top: 3px; color: var(--text); font-size: 13px; font-weight: 700; overflow-wrap: anywhere; }
.iu-actions { margin-top: 18px; display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 10px; }
.iu-actions button {
  min-height: 48px;
  padding: 10px 14px;
  border-radius: 12px;
  font-size: 13px;
  font-weight: 800;
  cursor: pointer;
}
.iu-primary { border: 1px solid transparent; background: linear-gradient(135deg,var(--accent),var(--accent-2)); color: #ffffff; box-shadow: 0 12px 28px rgba(35,121,198,.14); }
.iu-primary:hover:not(:disabled) { background: linear-gradient(135deg,#6db0f2,var(--accent)); }
.iu-secondary { border: 1px solid var(--line-strong); background: rgba(255,255,255,.035); color: var(--text); }
.iu-secondary:hover:not(:disabled) { border-color: rgba(35,121,198,.6); }
.iu-output-name { margin-top: 9px; color: var(--faint); font-size: 10px; text-align: center; overflow-wrap: anywhere; }
.iu-output-name code { color: var(--muted); font-family: ui-monospace, SFMono-Regular, Menlo, monospace; }
.iu-error, .iu-warning { margin-top: 12px; padding: 10px 12px; border-radius: 10px; font-size: 11px; line-height: 1.55; }
.iu-error { border: 1px solid rgba(248,113,113,.36); background: var(--danger-bg); color: var(--danger); }
.iu-warning { border: 1px solid rgba(246,179,90,.33); background: var(--warning-bg); color: var(--warning); }

.iu-preview-section, .iu-how-section, .iu-faq-section { padding: 72px 0; border-top: 1px solid rgba(255,255,255,.06); background: rgba(255,255,255,.014); }
.iu-preview-grid { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 18px; }
.iu-preview-card { min-width: 0; margin: 0; padding: 14px; border: 1px solid var(--line); border-radius: 17px; background: var(--surface); }
.iu-preview-card figcaption { display: flex; justify-content: space-between; gap: 10px; margin-bottom: 10px; color: var(--muted); font-size: 12px; }
.iu-preview-card figcaption strong { color: var(--text); font-size: 12px; }
.iu-preview-frame {
  height: 320px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border: 1px solid rgba(255,255,255,.08);
  border-radius: 12px;
  background: #090706;
}
.iu-preview-frame img { width: 100%; height: 100%; object-fit: contain; }
.iu-preview-placeholder { padding: 24px; color: var(--faint); font-size: 12px; text-align: center; }
.iu-empty-preview { padding: 58px 20px; border: 1px dashed var(--line-strong); border-radius: 17px; color: var(--faint); font-size: 13px; text-align: center; }

.iu-value-section { padding: 78px 0; border-top: 1px solid rgba(255,255,255,.06); }
.iu-value-grid, .iu-how-grid { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 15px; }
.iu-value-grid article, .iu-how-grid article { min-width: 0; padding: 21px; border: 1px solid var(--line); border-radius: 16px; background: var(--surface); }
.iu-value-grid article > span, .iu-how-grid article > b { color: var(--accent); font-size: 11px; letter-spacing: .08em; }
.iu-value-grid h3, .iu-how-grid h3 { margin: 9px 0 8px; color: var(--text); font-size: 19px; line-height: 1.28; }
.iu-value-grid p, .iu-how-grid p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.65; }
.iu-value-grid p + p, .iu-how-grid p + p { margin-top: 10px; }
.iu-next-links { margin-top: 18px; display: grid; grid-template-columns: repeat(5,minmax(0,1fr)); gap: 9px; }
.iu-next-links a { min-width: 0; padding: 11px 12px; border: 1px solid var(--line); border-radius: 10px; color: var(--muted); font-size: 11px; font-weight: 700; display: flex; justify-content: space-between; gap: 6px; }
.iu-next-links a:hover { border-color: rgba(35,121,198,.55); color: var(--accent-2); }
.iu-next-links span { color: var(--accent); }
.iu-next-links .iu-wide-link { grid-column: span 2; }

.iu-how-section { background: rgba(255,255,255,.025); }
.iu-how-grid article > b { display: inline-flex; width: 28px; height: 28px; border: 1px solid rgba(35,121,198,.36); border-radius: 999px; align-items: center; justify-content: center; }

.iu-faq-section { background: rgba(0,0,0,.08); }
.iu-faq-list { display: grid; gap: 10px; }
.iu-faq { overflow: hidden; border: 1px solid var(--line); border-radius: 13px; background: var(--surface); }
.iu-faq summary { position: relative; min-height: 62px; padding: 18px 48px 18px 18px; display: flex; align-items: center; color: var(--text); font-size: 13px; font-weight: 750; cursor: pointer; list-style: none; }
.iu-faq summary::-webkit-details-marker { display: none; }
.iu-faq summary::after { content: "+"; position: absolute; right: 18px; top: 50%; transform: translateY(-50%); color: var(--accent); font-size: 20px; font-weight: 400; }
.iu-faq[open] summary::after { content: "−"; }
.iu-faq > div { padding: 0 18px 18px; color: var(--muted); font-size: 12px; line-height: 1.7; }

.iu-footer { padding: 56px 0 28px; border-top: 1px solid var(--line); background: rgba(5,4,3,.72); }
.iu-footer-inner { width: min(1080px, calc(100% - 32px)); margin: 0 auto; }
.iu-footer-brand { display: flex; align-items: center; gap: 8px; margin-bottom: 28px; color: var(--text); font-weight: 800; }
.iu-footer-brand img { width: 30px; height: 30px; border-radius: 999px; }
.iu-footer-grid { display: grid; grid-template-columns: repeat(4,minmax(0,1fr)); gap: 28px; }
.iu-footer h3 { margin: 0 0 10px; color: var(--text); font-size: 14px; }
.iu-footer-grid a { display: block; margin-top: 7px; color: var(--faint); font-size: 11px; }
.iu-footer-grid a:hover { color: var(--accent); }
.iu-footer-bottom { margin-top: 32px; padding-top: 20px; border-top: 1px solid rgba(255,255,255,.08); color: rgba(168,180,194,.48); font-size: 10px; text-align: center; }

@media (max-width: 980px) {
  .iu-desktop-nav { gap: 13px; }
  .iu-desktop-nav a { font-size: 12px; }
  .iu-tool-grid { grid-template-columns: 1fr; }
  .iu-dropzone { min-height: 270px; }
  .iu-next-links { grid-template-columns: repeat(3,minmax(0,1fr)); }
  .iu-next-links .iu-wide-link { grid-column: span 2; }
}

@media (max-width: 760px) {
  .iu-container, .iu-narrow, .iu-mid, .iu-footer-inner { width: calc(100% - 26px); }
  .iu-header-inner { width: calc(100% - 26px); min-height: 64px; gap: 8px; }
  .iu-brand { font-size: 17px; margin-right: auto; }
  .iu-brand img { width: 30px; height: 30px; }
  .iu-desktop-nav, .iu-header-cta { display: none; }
  .iu-mobile-toggle { display: inline-flex; align-items: center; justify-content: center; }
  .iu-mobile-menu { display: grid; gap: 2px; padding: 8px 13px 13px; border-top: 1px solid rgba(255,255,255,.06); background: rgba(10,12,17,.97); }
  .iu-mobile-menu a { padding: 9px 8px; border-radius: 8px; color: var(--muted); font-size: 13px; }
  .iu-mobile-menu a:hover { background: var(--surface); color: var(--accent); }
  .iu-intro { padding: 34px 0 24px; }
  .iu-intro h1 { font-size: 2.18rem; }
  .iu-intro p { font-size: 14px; }
  .iu-tool-section { padding: 24px 0 56px; }
  .iu-section-heading { margin-bottom: 22px; }
  .iu-section-heading h2 { font-size: 25px; }
  .iu-section-heading p { font-size: 13px; }
  .iu-card { padding: 18px; border-radius: 15px; }
  .iu-dropzone { min-height: 245px; padding: 16px; }
  .iu-source-preview-frame { height: 165px; }
  .iu-print-preset-grid { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .iu-actions { grid-template-columns: 1fr; }
  .iu-actions button { min-height: 50px; }
  .iu-preview-section, .iu-value-section, .iu-how-section, .iu-faq-section { padding: 58px 0; }
  .iu-preview-grid, .iu-value-grid, .iu-how-grid { grid-template-columns: 1fr; }
  .iu-preview-frame { height: 245px; }
  .iu-next-links { grid-template-columns: repeat(2,minmax(0,1fr)); }
  .iu-next-links .iu-wide-link { grid-column: 1 / -1; }
  .iu-footer-grid { grid-template-columns: repeat(2,minmax(0,1fr)); gap: 24px 18px; }
}

@media (max-width: 430px) {
  .iu-brand em { display: none; }
  .iu-intro h1 { font-size: 2rem; }
  .iu-privacy-row { gap: 6px; }
  .iu-privacy-row span { padding: 5px 8px; font-size: 10px; }
  .iu-factor-grid { grid-template-columns: 1fr 1fr 1fr; gap: 6px; }
  .iu-factor-grid button { padding: 8px 7px; }
  .iu-field input, .iu-field select { min-height: 46px; }
  .iu-summary { grid-template-columns: 1fr; }
  .iu-summary > div, .iu-summary > div:nth-child(odd), .iu-summary > div:nth-last-child(-n+2) { border-right: 0; border-bottom: 1px solid var(--line); }
  .iu-summary > div:last-child { border-bottom: 0; }
  .iu-next-links { grid-template-columns: 1fr; }
  .iu-next-links .iu-wide-link { grid-column: auto; }
  .iu-footer-grid { grid-template-columns: 1fr; gap: 22px; }
}

@media (prefers-reduced-motion: reduce) {
  .iu-page *, .iu-page *::before, .iu-page *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; }
}