:root {
  --bg: #faf8f5; --surface: #ffffff; --ink: #1d1b19; --muted: #6b655e; --line: #e6e1da;
  --accent: #d93b2b; --accent-ink: #ffffff; --accent-soft: #fdecea; --ok: #1f7a4d; --ok-soft: #e7f5ee; --err: #b42318;
  --radius: 14px; --shadow: 0 1px 2px rgba(0,0,0,.04), 0 4px 16px rgba(0,0,0,.05);
  --font: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #161412; --surface: #201e1b; --ink: #f2eee9; --muted: #a59e95; --line: #35312c;
    --accent: #f05a48; --accent-soft: #3a1f1b; --ok: #4cc38a; --ok-soft: #17301f; --err: #ff8577;
    --shadow: 0 1px 2px rgba(0,0,0,.3);
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.6 var(--font); }
a { color: var(--accent); }
img, svg { max-width: 100%; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 16px; top: 8px; background: var(--surface); padding: 8px 12px; z-index: 10; }
.wrap { max-width: 1160px; margin: 0 auto; padding: 0 16px; }

/* header / footer */
.site-header { border-bottom: 1px solid var(--line); background: var(--surface); }
.bar { display: flex; align-items: center; justify-content: space-between; height: 60px; gap: 16px; }
.logo { text-decoration: none; font-weight: 800; font-size: 22px; letter-spacing: -.02em; color: var(--ink); }
.logo-mark { background: var(--accent); color: var(--accent-ink); padding: 2px 7px; border-radius: 7px; }
.logo-dash { margin-left: 2px; }
.brand { position: relative; }
.region-flag { position: absolute; top: calc(100% + 26px); left: 0; display: flex; align-items: center; gap: 6px; font-size: 12px; font-weight: 700; letter-spacing: .06em; color: var(--muted); white-space: nowrap; }
.region-flag[hidden] { display: none; }
.region-flag svg { display: block; border-radius: 2px; box-shadow: 0 0 0 1px var(--line); }
.site-header nav { display: flex; gap: 18px; font-size: 15px; }
.site-header nav a { color: var(--ink); text-decoration: none; }
.site-header nav a:hover { color: var(--accent); }
.site-footer { border-top: 1px solid var(--line); margin-top: 56px; padding: 28px 0; color: var(--muted); font-size: 15px; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 6px 18px; margin: 8px 0; }
.site-footer a { color: var(--muted); }
.small { font-size: 13px; }

/* layout: content + ad rail on wide screens */
.layout { display: grid; grid-template-columns: minmax(0, 1fr); gap: 40px; }
.content { max-width: 760px; width: 100%; margin: 0 auto; }
.rail { display: none; }
@media (min-width: 1100px) {
  .layout { grid-template-columns: minmax(0, 1fr) 300px; }
  .content { margin: 0; }
  .rail { display: block; padding-top: 32px; }
  .rail .ad { position: sticky; top: 24px; min-height: 600px; }
}

/* hero + tool */
.hero { text-align: center; padding: 36px 0 8px; }
.hero h1 { font-size: clamp(32px, 6vw, 48px); line-height: 1.1; margin: 0 0 12px; letter-spacing: -.03em; }
.lead { font-size: 19px; color: var(--muted); margin: 0 auto; max-width: 600px; }
.tool { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: 20px; margin: 24px 0; }
.drop { display: flex; flex-direction: column; align-items: center; gap: 4px; padding: 40px 16px; border: 2px dashed var(--line); border-radius: 12px; cursor: pointer; color: var(--accent); background: var(--accent-soft); transition: border-color .15s, padding .15s; text-align: center; }
.drop:hover, .drop.active, .drop:focus-within { border-color: var(--accent); }
.drop.compact { padding: 14px 16px; flex-direction: row; justify-content: center; gap: 12px; }
.drop.compact svg { width: 28px; height: 28px; }
.drop.compact .drop-sub { display: none; }
.drop-title { font-weight: 700; font-size: 20px; color: var(--accent); }
.drop-sub { color: var(--muted); font-size: 15px; }

.files { list-style: none; margin: 16px 0 0; padding: 0; display: grid; gap: 8px; }
.file { display: flex; align-items: center; gap: 10px; padding: 10px 10px 10px 8px; border: 1px solid var(--line); border-radius: 10px; background: var(--bg); cursor: grab; }
.file.dragging { opacity: .45; }
.file.over { border-color: var(--accent); box-shadow: 0 -3px 0 var(--accent); }
.file.bad { border-color: var(--err); }
.file.bad .fmeta { color: var(--err); }
.grip { color: var(--muted); font-size: 14px; letter-spacing: -2px; user-select: none; }
.num { width: 26px; height: 26px; border-radius: 50%; background: var(--accent); color: var(--accent-ink); display: grid; place-items: center; font-size: 13px; font-weight: 700; flex: none; }
.info { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.fname { font-weight: 600; font-size: 15px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.fmeta { font-size: 13px; color: var(--muted); }
.ctrl { display: flex; gap: 4px; flex: none; }
.ctrl button { width: 34px; height: 34px; border: 1px solid var(--line); background: var(--surface); color: var(--ink); border-radius: 8px; cursor: pointer; font-size: 15px; }
.ctrl button:hover:not(:disabled) { border-color: var(--accent); color: var(--accent); }
.ctrl button:disabled { opacity: .35; cursor: default; }
.hint { font-size: 14px; color: var(--muted); margin: 10px 2px 0; }

.actions { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; justify-content: space-between; margin-top: 16px; }
.name-field { display: flex; align-items: center; gap: 6px; font-size: 14px; color: var(--muted); }
.name-field input { font: inherit; color: var(--ink); background: var(--bg); border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; width: 150px; }
.buttons { display: flex; flex-wrap: wrap; gap: 8px; }
.btn { display: inline-block; font: 600 16px/1 var(--font); padding: 13px 20px; border-radius: 10px; border: 0; background: var(--accent); color: var(--accent-ink); cursor: pointer; text-decoration: none; }
.btn:hover { filter: brightness(1.06); }
.btn:disabled { opacity: .45; cursor: not-allowed; filter: none; }
.btn.ghost { background: transparent; color: var(--ink); border: 1px solid var(--line); }
.btn.big { font-size: 18px; padding: 16px 32px; }
.linkish { background: none; border: 0; color: var(--muted); text-decoration: underline; cursor: pointer; font: inherit; font-size: 14px; display: block; margin: 14px auto 0; }
.status { min-height: 1.6em; margin: 12px 0 0; font-size: 15px; color: var(--muted); }
.status.error { color: var(--err); }
.result { margin-top: 12px; padding: 24px; border-radius: 12px; background: var(--ok-soft); text-align: center; }
.result-title { font-size: 20px; font-weight: 700; color: var(--ok); margin: 0; }
.result-meta { color: var(--muted); margin: 4px 0 18px; }

/* ads — reserved height avoids layout shift; spacing keeps them clear of tool buttons */
.ad { margin: 32px 0; min-height: 280px; text-align: center; }
.ad-label { display: block; font-size: 11px; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); margin-bottom: 4px; }
.ad-below-tool { margin-top: 40px; }

/* prose */
.prose h1 { font-size: clamp(30px, 5vw, 40px); line-height: 1.15; letter-spacing: -.02em; margin: 28px 0 8px; }
.prose h2 { font-size: 26px; line-height: 1.25; margin: 40px 0 12px; letter-spacing: -.01em; }
.prose h3 { font-size: 19px; margin: 24px 0 6px; }
.prose p, .prose li { color: var(--ink); }
.prose code { background: var(--accent-soft); padding: 1px 5px; border-radius: 5px; font-size: .92em; }
.prose blockquote { margin: 16px 0; padding: 4px 16px; border-left: 3px solid var(--accent); color: var(--muted); }
.prose table { border-collapse: collapse; width: 100%; font-size: 15px; display: block; overflow-x: auto; }
.prose th, .prose td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; }
.crumbs { font-size: 14px; color: var(--muted); margin: 24px 0 0; }
.crumbs a { color: var(--muted); }
.meta { color: var(--muted); font-size: 14px; margin: 0 0 24px; }
.steps li { margin-bottom: 8px; }
.features { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px; }
.features > div { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; }
.features h3 { margin: 0 0 6px; font-size: 17px; }
.features p { margin: 0; font-size: 15px; color: var(--muted); }
details { border-bottom: 1px solid var(--line); padding: 12px 0; }
summary { cursor: pointer; font-weight: 600; }
details p { margin: 8px 0 0; color: var(--muted); }
.guide-list { list-style: none; padding: 0; display: grid; gap: 10px; }
.guide-list li { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 14px 16px; }
.guide-list a { text-decoration: none; display: block; color: var(--ink); }
.guide-list a:hover strong { color: var(--accent); }
.guide-list span { display: block; color: var(--muted); font-size: 15px; }
.cta { margin: 40px 0; padding: 24px; border-radius: var(--radius); background: var(--accent-soft); text-align: center; }
.cta h2 { margin: 0 0 6px; }
.related ul { padding-left: 20px; }

@media (max-width: 560px) {
  body { font-size: 16px; }
  .site-header nav { gap: 12px; font-size: 14px; }
  .tool { padding: 14px; }
  .actions { flex-direction: column; align-items: stretch; }
  .buttons { display: grid; grid-template-columns: 1fr 1fr; }
  #merge-btn { grid-column: 1 / -1; padding: 16px; }
  .name-field input { flex: 1; }
}