:root {
  --fg: #1c1d21; --muted: #5d6170; --line: #e3e5ea; --bg: #ffffff; --bg2: #f6f7f9;
  --accent: #1f6feb; --accent-fg: #ffffff; --ok: #1a7f37; --warn: #9a6700;
  --code-bg: #0f1420; --code-fg: #e6edf3;
}
@media (prefers-color-scheme: dark) {
  :root { --fg: #e8eaee; --muted: #a2a7b3; --line: #2b2f37; --bg: #111317; --bg2: #181b21; --accent: #4c8dff; --code-bg: #0b0e14; }
}
* { box-sizing: border-box; }
body { margin: 0; font: 16px/1.65 -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Noto Sans JP", Meiryo, sans-serif; color: var(--fg); background: var(--bg); }
a { color: var(--accent); }
.wrap { max-width: 980px; margin: 0 auto; padding: 0 20px; }
header.top { border-bottom: 1px solid var(--line); }
header.top .wrap { display: flex; align-items: center; justify-content: space-between; height: 60px; gap: 16px; }
.brand { font-weight: 700; text-decoration: none; color: var(--fg); letter-spacing: -0.01em; }
.brand span { color: var(--accent); }
nav a { margin-left: 18px; color: var(--muted); text-decoration: none; font-size: 14px; }
nav a:hover { color: var(--fg); }
.hero { padding: 72px 0 48px; }
.hero h1 { font-size: clamp(30px, 5vw, 46px); line-height: 1.15; margin: 0 0 16px; letter-spacing: -0.02em; }
.hero p.lead { font-size: 19px; color: var(--muted); max-width: 640px; margin: 0 0 28px; }
.btn { display: inline-block; padding: 12px 20px; border-radius: 8px; background: var(--accent); color: var(--accent-fg); text-decoration: none; font-weight: 600; }
.btn.ghost { background: transparent; color: var(--accent); border: 1px solid var(--line); margin-left: 8px; }
.note { font-size: 13px; color: var(--muted); margin-top: 12px; }
.compare { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 8px 0 56px; }
.compare figure { margin: 0; }
.compare figcaption { font-size: 13px; color: var(--muted); margin-bottom: 6px; }
pre { margin: 0; padding: 16px; border-radius: 10px; background: var(--code-bg); color: var(--code-fg); font: 13px/1.5 ui-monospace, Menlo, Consolas, monospace; overflow-x: auto; }
section { padding: 40px 0; border-top: 1px solid var(--line); }
section h2 { font-size: 26px; margin: 0 0 20px; letter-spacing: -0.01em; }
.grid3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.card { border: 1px solid var(--line); border-radius: 12px; padding: 20px; background: var(--bg); }
.card h3 { margin: 0 0 8px; font-size: 17px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }
.price { font-size: 34px; font-weight: 700; margin: 6px 0; }
.price small { font-size: 15px; color: var(--muted); font-weight: 400; }
ol.steps { padding-left: 20px; } ol.steps li { margin: 8px 0; }
table { border-collapse: collapse; width: 100%; font-size: 15px; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-weight: 600; width: 32%; }
.ok { color: var(--ok); font-weight: 600; } .warn { color: var(--warn); font-weight: 600; }
details { border-bottom: 1px solid var(--line); padding: 12px 0; } summary { cursor: pointer; font-weight: 600; }
footer { border-top: 1px solid var(--line); padding: 28px 0 40px; font-size: 13px; color: var(--muted); }
footer a { color: var(--muted); margin-right: 16px; }
.doc { padding-top: 40px; padding-bottom: 60px; max-width: 760px; } .doc h1 { font-size: 30px; } .doc h2 { font-size: 20px; margin-top: 32px; }
@media (max-width: 760px) { .compare, .grid3 { grid-template-columns: 1fr; } nav a:not(.lang) { display: none; } .btn.ghost { margin: 10px 0 0; } }

/* Online converter (converter.js) */
.tool { border: 1px solid var(--line); border-radius: 14px; padding: 22px; background: var(--bg2); margin: 8px 0 48px; }
.drop { border: 2px dashed var(--line); border-radius: 10px; padding: 26px 16px; text-align: center; cursor: pointer; color: var(--muted); background: var(--bg); }
.drop.over { border-color: var(--accent); }
.tool textarea { width: 100%; min-height: 130px; font: 13px/1.45 ui-monospace, Menlo, Consolas, monospace; border: 1px solid var(--line); border-radius: 8px; padding: 10px; background: var(--bg); color: var(--fg); }
.tool button.btn { border: 0; cursor: pointer; font: inherit; font-weight: 600; }
.tool .btn.ghost { border: 1px solid var(--line); margin-left: 0; }
.btn.small { padding: 5px 12px; font-size: 13px; margin-left: 6px; }
.hidden { display: none; }
.finding { display: flex; gap: 8px; margin: 6px 0; font-size: 14px; }
.tag { font-size: 12px; border-radius: 4px; padding: 0 7px; white-space: nowrap; height: fit-content; }
.t-ok { background: #e6f4ea; color: #1a7f37; } .t-review { background: #fef7e0; color: #9a6700; } .t-no { background: #fce8e6; color: #c5221f; }
.error { background: #fce8e6; color: #c5221f; border-radius: 8px; padding: 10px 12px; margin: 10px 0; font-size: 14px; }
.file-head { display: flex; justify-content: space-between; align-items: center; margin-top: 14px; }
.spinner { width: 30px; height: 30px; border: 3px solid var(--line); border-top-color: var(--accent); border-radius: 50%; animation: spin 1s linear infinite; margin: 24px auto 10px; }
@keyframes spin { to { transform: rotate(360deg); } }

/* Articles */
.article { max-width: 820px; }
.article pre { margin: 12px 0; max-height: 520px; }
.article code { font: 0.92em ui-monospace, Menlo, Consolas, monospace; }
.article blockquote { margin: 12px 0; padding: 4px 16px; border-left: 3px solid var(--line); color: var(--muted); }
.article table { margin: 12px 0; display: block; overflow-x: auto; }