:root{
  --bg:#e9f3e9; --card:#ffffff; --line:#dde6dd; --txt:#1a1f2e; --muted:#5f6b66;
  --accent:#2563eb; --accent-soft:rgba(37,99,235,.10); --good:#16a34a; --bad:#dc2626; --warn:#d97706;
  --shadow:0 1px 2px rgba(16,24,40,.05); --shadow-lg:0 12px 30px rgba(16,24,40,.10);
}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Inter,Roboto,Helvetica,Arial,sans-serif;
     background:var(--bg);color:var(--txt);line-height:1.5}
a{color:var(--accent)}

/* ---- shared top navigation: brand + pills ---- */
.topnav{position:sticky;top:0;z-index:20;display:flex;align-items:center;gap:14px;flex-wrap:wrap;
        padding:11px 24px;background:rgba(255,255,255,.82);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);
        border-bottom:1px solid var(--line)}
.topnav .brand{font-weight:700;font-size:1.05rem;text-decoration:none;color:var(--txt);white-space:nowrap}
.topnav .pills{display:flex;gap:3px;flex-wrap:wrap;margin-left:auto;background:#dcead9;padding:4px;border-radius:11px}
.topnav .pills a{color:var(--muted);text-decoration:none;font-size:.82rem;padding:6px 12px;border-radius:8px;white-space:nowrap}
.topnav .pills a:hover{color:var(--txt)}
.topnav .pills a.active{background:#fff;color:var(--accent);box-shadow:var(--shadow);font-weight:600}
.sharebtn{margin-left:8px;background:var(--accent);color:#fff;border:none;padding:7px 14px;border-radius:9px;
          font-size:.82rem;font-weight:600;cursor:pointer;white-space:nowrap;box-shadow:var(--shadow)}
.sharebtn:hover{filter:brightness(1.07)}
.langtoggle{display:flex;gap:2px;background:#dcead9;padding:3px;border-radius:9px;margin-left:auto}
.langtoggle button{background:none;border:none;color:var(--muted);font-size:.8rem;padding:5px 11px;border-radius:7px;cursor:pointer;font-family:inherit}
.langtoggle button.active{background:#fff;color:var(--accent);font-weight:700;box-shadow:var(--shadow)}
.zh-only{display:none}
body.lang-zh .zh-only{display:revert}
body.lang-zh .en-only{display:none}

header{padding:30px 20px 12px;text-align:center}
header h1{margin:0 0 6px;font-size:1.55rem;letter-spacing:-.02em}
header p{margin:0;color:var(--muted);font-size:.92rem}

.wrap{max-width:1080px;margin:0 auto;padding:20px}
.grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}
@media(max-width:820px){.grid{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:18px;box-shadow:var(--shadow)}
.card h2{margin:0 0 14px;font-size:1.02rem;display:flex;align-items:center;gap:8px}
.card h2 .dot{width:9px;height:9px;border-radius:50%;background:var(--accent)}
.row{display:flex;align-items:center;justify-content:space-between;gap:10px;margin:9px 0}
.row label{flex:1;font-size:.9rem;color:#3a4256}
.row .hint{display:block;color:var(--muted);font-size:.72rem;margin-top:1px}
.row input,.row select,.row textarea{width:130px;padding:7px 9px;background:#fff;color:var(--txt);
     border:1px solid var(--line);border-radius:8px;font-size:.9rem;text-align:right}
.row input:focus,.row select:focus,.row textarea:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
.row select{text-align:left}
.row textarea{width:100%;text-align:left;font-family:ui-monospace,Menlo,Consolas,monospace;font-size:.8rem}
.ig{display:flex;gap:6px;width:130px}
.ig input{width:80px}
.ig select{width:auto;flex:1;min-width:0}
.full{grid-column:1 / -1}
.results{grid-column:1 / -1}
.resgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:12px}
.metric{background:linear-gradient(180deg,#fff,#fbfcfe);border:1px solid var(--line);border-radius:12px;padding:12px 14px}
.metric .k{font-size:.72rem;color:var(--muted);text-transform:uppercase;letter-spacing:.04em}
.metric .v{font-size:1.35rem;font-weight:700;margin-top:3px;color:var(--accent)}
.metric .u{font-size:.8rem;color:var(--muted);font-weight:400}
.margin-box{margin-top:16px;padding:16px;border-radius:12px;text-align:center;font-weight:600;font-size:1.1rem}
.margin-good{background:rgba(22,163,74,.10);border:1px solid var(--good);color:var(--good)}
.margin-bad{background:rgba(220,38,38,.10);border:1px solid var(--bad);color:var(--bad)}
.margin-warn{background:rgba(217,119,6,.10);border:1px solid var(--warn);color:var(--warn)}
details{margin-top:14px;background:#fbfcfe;border:1px solid var(--line);border-radius:10px;padding:12px 16px}
details summary{cursor:pointer;color:var(--accent);font-size:.9rem}
table{width:100%;border-collapse:collapse;margin-top:10px;font-size:.85rem}
th,td{padding:7px 8px;border-bottom:1px solid var(--line);text-align:left}
th{color:var(--muted);font-weight:600;font-size:.78rem;text-transform:uppercase;letter-spacing:.03em}
td.num{text-align:right;font-variant-numeric:tabular-nums}
td:last-child{text-align:right;font-variant-numeric:tabular-nums}
/* Ad slots stay in the markup so they can be filled later, but the AdSense
   script in each <head> is still commented out — until it is live, an empty
   dashed "Ad placeholder" box just makes a finished site look unfinished.
   To enable: uncomment the adsbygoogle script and drop this display:none. */
.adslot{display:none;margin:18px 0;min-height:90px;align-items:center;justify-content:center;
        background:#fff;border:1px dashed #cfd4dc;border-radius:12px;color:var(--muted);font-size:.8rem}
label[for]{cursor:pointer}
.preset-bar{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:18px;justify-content:center}
.preset-bar button{background:#fff;border:1px solid var(--line);color:var(--txt);
     padding:7px 13px;border-radius:20px;font-size:.83rem;cursor:pointer;box-shadow:var(--shadow)}
.preset-bar button:hover{border-color:var(--accent);color:var(--accent)}

/* ---- tool-page "bring this value back to Link Budget" return bar ---- */
.linkback-bar{display:flex;justify-content:center;padding:10px 16px;background:var(--accent)}
.linkback-btn{background:#fff;color:var(--accent);border:none;padding:7px 16px;border-radius:20px;
     font-size:.85rem;font-weight:700;cursor:pointer;font-family:inherit;box-shadow:var(--shadow)}
.linkback-btn:disabled{opacity:.6;cursor:default}
.linkback-btn:not(:disabled):hover{filter:brightness(1.05)}

/* ---- link-budget.html: jump-out links to the source-tool calculators ---- */
.jump-links{display:block;margin-top:2px}
.jump-link{font-size:.72rem;color:var(--accent);text-decoration:none;margin-right:10px;white-space:nowrap}
.jump-link:hover{text-decoration:underline}

/* ---- scenario save/compare panel ---- */
.scenario-panel{display:none;margin:0 0 18px}
.scenario-panel.open{display:block}
.scenario-save-row{display:flex;gap:8px;margin-bottom:14px}
.scenario-save-row input{flex:1;padding:7px 10px;border:1px solid var(--line);border-radius:8px;font-size:.88rem;background:#fff;color:var(--txt)}
.scenario-save-row button{background:var(--accent);color:#fff;border:none;padding:7px 16px;border-radius:9px;
     font-size:.85rem;font-weight:600;cursor:pointer;font-family:inherit;white-space:nowrap}
.scenario-row{display:flex;align-items:center;gap:10px;padding:9px 4px;border-bottom:1px solid var(--line);font-size:.88rem}
.scenario-row:last-child{border-bottom:none}
.scenario-row .name{flex:1;font-weight:600;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.scenario-row .mode-badge{font-size:.7rem;padding:2px 8px;border-radius:20px;background:var(--accent-soft);color:var(--accent);white-space:nowrap}
.scenario-row .ts{color:var(--muted);font-size:.76rem;white-space:nowrap}
.scenario-row button{background:#fff;border:1px solid var(--line);padding:4px 10px;border-radius:14px;
     font-size:.76rem;cursor:pointer;font-family:inherit;white-space:nowrap}
.scenario-row button:hover{border-color:var(--accent);color:var(--accent)}
.scenario-row button.danger:hover{border-color:var(--bad);color:var(--bad)}
.scenario-empty{color:var(--muted);font-size:.85rem;padding:10px 0;text-align:center}
.scenario-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:10px}
footer{text-align:center;color:var(--muted);font-size:.8rem;padding:24px 20px;border-top:1px solid var(--line)}
.article{color:#454c5e;font-size:.9rem;line-height:1.7;margin-top:8px}
.article h2{color:var(--txt);font-size:1.1rem;margin-top:22px}
.article code{background:#eef0f4;padding:2px 6px;border-radius:5px;color:var(--txt)}
.note{background:#eef4ff;border:1px solid #cfe0ff;color:#1d4ed8;border-radius:10px;padding:10px 14px;font-size:.85rem;margin:12px 0}
.howto{margin:4px 0 0;padding-left:24px;color:#454c5e;font-size:.92rem;line-height:1.7}
.howto li{margin:8px 0}
.howto li::marker{color:var(--accent);font-weight:700}
.howto b{color:var(--txt)}
.howto .cn{display:block;color:var(--muted);font-size:.86rem;margin-top:2px}

/* ---- MathWorks-style examples gallery (home) ---- */
.pagehead{border-bottom:1px solid var(--line);background:#fff}
.pagehead .inner{max-width:1180px;margin:0 auto;padding:26px 20px 22px}
.pagehead h1{margin:0 0 6px;font-size:1.6rem;letter-spacing:-.02em}
.pagehead p{margin:0;color:var(--muted);font-size:.95rem}
.gallery{display:grid;grid-template-columns:228px 1fr;gap:30px;max-width:1180px;margin:0 auto;padding:24px 20px 60px}
@media(max-width:800px){.gallery{grid-template-columns:1fr;gap:18px}}
.sidebar{position:sticky;top:70px;align-self:start}
@media(max-width:800px){.sidebar{position:static}}
.sidebar h3{font-size:.72rem;text-transform:uppercase;letter-spacing:.07em;color:var(--muted);margin:0 0 10px}
.cat-list{list-style:none;margin:0;padding:0}
.cat-list li{margin:2px 0}
.cat-list button{width:100%;text-align:left;background:none;border:none;color:#3a4256;font-size:.9rem;
  padding:9px 12px;border-radius:9px;cursor:pointer;font-family:inherit;display:flex;justify-content:space-between;align-items:center;gap:8px}
.cat-list button:hover{background:#fff}
.cat-list button.active{background:#fff;color:var(--accent);font-weight:600;box-shadow:var(--shadow)}
.cat-list .ct{color:var(--muted);font-size:.76rem;background:#eef0f4;border-radius:20px;padding:1px 8px}
.cat-list button.active .ct{background:var(--accent-soft);color:var(--accent)}
.main-head{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:18px;flex-wrap:wrap}
.main-head .count{font-size:.9rem;color:var(--muted)}
.search{flex:1;max-width:340px;position:relative;min-width:200px}
.search input{width:100%;padding:9px 12px 9px 36px;border:1px solid var(--line);border-radius:10px;font-size:.9rem;background:#fff;color:var(--txt)}
.search input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
.search svg{position:absolute;left:11px;top:50%;transform:translateY(-50%);opacity:.5}
.tool-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(258px,1fr));gap:20px}
.tcard{display:flex;flex-direction:column;text-decoration:none;color:inherit;background:#fff;
  border:1px solid var(--line);border-radius:14px;overflow:hidden;box-shadow:var(--shadow);transition:transform .15s,box-shadow .15s,border-color .15s}
.tcard:hover{border-color:var(--accent);transform:translateY(-3px);box-shadow:var(--shadow-lg)}
.tcard .thumb{display:block;width:100%;height:138px;border-bottom:1px solid var(--line)}
.tcard .body{padding:15px 16px 17px}
.tcard .tag{display:inline-block;font-size:.7rem;color:var(--accent);background:var(--accent-soft);padding:3px 10px;border-radius:20px;margin-bottom:9px}
.tcard h3{margin:0 0 6px;font-size:1.02rem}
.tcard p{margin:0;color:var(--muted);font-size:.85rem;line-height:1.5}
.empty{grid-column:1/-1;color:var(--muted);padding:48px;text-align:center}

/* ---- sub-page layout: left tool sidebar + main ---- */
.page{display:grid;grid-template-columns:228px 1fr;gap:30px;max-width:1180px;margin:0 auto;padding:8px 20px 40px}
@media(max-width:800px){.page{grid-template-columns:1fr;gap:0;padding-top:0}.page .sidebar{display:none}}
.pagemain{min-width:0}
.pagemain header{text-align:left;padding:20px 0 6px}
.pagemain .wrap{max-width:none;margin:0;padding:14px 0}
.toolnav{list-style:none;margin:0;padding:0}
.toolnav .home{display:block;text-decoration:none;color:var(--muted);font-size:.84rem;padding:6px 12px;margin-bottom:6px}
.toolnav .home:hover{color:var(--accent)}
.toolnav .grp{font-size:.7rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);margin:14px 0 4px;padding:0 12px}
.toolnav a:not(.home){display:block;text-decoration:none;color:#3a4256;font-size:.88rem;padding:7px 12px;border-radius:8px}
.toolnav a:not(.home):hover{background:#fff}
.toolnav a.active{background:#fff;color:var(--accent);font-weight:600;box-shadow:var(--shadow)}

/* ---- hub home page (legacy hero/cards, still used elsewhere) ---- */
.hero{text-align:center;padding:62px 20px 34px;background:radial-gradient(900px 360px at 50% -40px,rgba(34,160,90,.14),transparent)}
.hero .tag{display:inline-block;font-size:.78rem;color:var(--accent);background:var(--accent-soft);
           border:1px solid rgba(37,99,235,.25);padding:5px 12px;border-radius:20px;margin-bottom:18px}
.hero h1{font-size:2.4rem;margin:0 0 12px;letter-spacing:-.025em}
.hero p{color:var(--muted);font-size:1.05rem;margin:0 auto;max-width:580px}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:18px}
.tool{display:block;text-decoration:none;color:inherit;background:var(--card);border:1px solid var(--line);
      border-radius:16px;padding:22px;box-shadow:var(--shadow);transition:transform .15s,box-shadow .15s,border-color .15s}
.tool:hover{border-color:var(--accent);transform:translateY(-3px);box-shadow:var(--shadow-lg)}
.tool .ic{font-size:1.8rem}
.tool h3{margin:12px 0 6px;font-size:1.05rem}
.tool p{margin:0;color:var(--muted);font-size:.85rem;line-height:1.5}
.tool .go{margin-top:14px;color:var(--accent);font-size:.82rem;font-weight:600}