:root{--ink:#07131f;--panel:#0c1e2e;--white:#f7fffa;--muted:#9eb3bf;--line:#284658;--green:#078930;--green2:#38cb6e;--yellow:#fcdd09;--red:#da121a;--host:#5e7585}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;min-height:100vh;background:var(--ink);color:var(--white);font:16px/1.5 Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif}button,input{font:inherit}button,a{touch-action:manipulation}.flag-line{height:4px;background:linear-gradient(90deg,var(--green) 0 33.33%,var(--yellow) 33.33% 66.66%,var(--red) 66.66%)}.topbar{min-height:78px;padding:14px max(22px,calc((100vw - 1440px)/2));display:flex;align-items:center;justify-content:space-between;gap:24px;border-bottom:1px solid #ffffff16;background:#07131fed;backdrop-filter:blur(12px);position:sticky;top:0;z-index:20}.brand{display:flex;align-items:center;gap:12px;color:inherit;text-decoration:none}.mark{width:48px;height:48px;border-radius:14px;display:grid;place-items:center;background:var(--green);font-weight:950}.brand strong,.brand small{display:block}.brand small{color:var(--muted);font-size:.75rem}.header-actions{display:flex;gap:10px}.ghost{display:inline-flex;align-items:center;justify-content:center;border:1px solid #315064;border-radius:11px;background:#10283a;color:#eef8fb;text-decoration:none;padding:10px 14px;font-weight:800;cursor:pointer}
main,footer{width:min(1440px,calc(100% - 44px));margin:auto}.intro{display:flex;align-items:end;justify-content:space-between;gap:60px;padding:54px 0 36px}.intro h1{font-size:clamp(2.8rem,5vw,5.2rem);line-height:.94;letter-spacing:-.06em;margin:8px 0 0}.intro h1 span{color:var(--green2)}.intro>p{max-width:490px;color:var(--muted);font-size:1.05rem;margin:0}.kicker{font-size:.72rem;text-transform:uppercase;letter-spacing:.16em;color:#79e39a;font-weight:900;margin:0 0 7px}.workspace{display:grid;grid-template-columns:330px 1fr;gap:20px;padding-bottom:64px}.controls-card,.summary-card,.boundary-card,.subnets-card{border:1px solid var(--line);border-radius:24px;background:linear-gradient(145deg,var(--panel),#091924);box-shadow:0 22px 60px #0004}.controls-card{padding:25px;align-self:start;position:sticky;top:98px}.controls-card h2,.section-head h2{font-size:1.55rem;letter-spacing:-.03em;margin:0}.controls-card label{display:block;color:#c4d6df;font-size:.8rem;font-weight:850;margin-top:22px}#cidrInput{width:100%;display:block;margin-top:8px;border:1px solid #335367;border-radius:12px;background:#061521;color:#fff;padding:13px 14px;outline:0}.controls-card input:focus{border-color:var(--green2);box-shadow:0 0 0 3px #38cb6e20}.input-help{color:var(--muted);font-size:.78rem}.prefix-head{display:flex;justify-content:space-between;align-items:end;margin-top:20px}.prefix-head label{margin:0}.prefix-head output{font-size:1.35rem;font-weight:950;color:var(--yellow)}input[type=range]{width:100%;accent-color:var(--yellow);margin:14px 0 0}.range-labels{display:flex;justify-content:space-between;color:#78909e;font-size:.72rem}.quick-scenarios{display:grid;gap:8px;margin-top:24px}.quick-scenarios>span{text-transform:uppercase;letter-spacing:.12em;color:#78909e;font-size:.7rem;font-weight:900}.quick-scenarios button{border:1px solid #2e4c5f;background:#0a1925;color:#d7e7ed;border-radius:10px;padding:10px;text-align:left;cursor:pointer;font-weight:750}.quick-scenarios button:hover{border-color:#6b8b9e}.legend{display:grid;gap:8px;padding-top:20px;margin-top:22px;border-top:1px solid var(--line);color:var(--muted);font-size:.78rem}.legend div{display:flex;align-items:center;gap:9px}.legend i{width:14px;height:14px;border-radius:4px}.legend .original,.bit.original{background:var(--green)}.legend .borrowed,.bit.borrowed{background:var(--yellow);color:var(--ink)}.legend .hosts,.bit.hosts{background:var(--host)}.error{margin-top:18px;padding:12px;background:#3b171e;border:1px solid #79313f;border-radius:11px;color:#ffd9df;font-size:.82rem}
.results{display:grid;gap:20px}.summary-card,.boundary-card,.subnets-card{padding:26px}.section-head{display:flex;align-items:start;justify-content:space-between;gap:20px}.valid-badge{border:1px solid #27734a;background:#0e3824;color:#baf4cb;border-radius:999px;padding:7px 11px;font-size:.75rem;font-weight:850}.metric-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:22px}.metric-grid article{padding:17px;border:1px solid #29495b;border-radius:15px;background:#081722}.metric-grid span,.bit-summary span{display:block;text-transform:uppercase;letter-spacing:.08em;font-size:.68rem;color:#8299a6;font-weight:850}.metric-grid strong{display:block;font:850 1.03rem/1.25 ui-monospace,SFMono-Regular,Consolas,monospace;margin:8px 0 5px;word-break:break-word}.metric-grid small{color:var(--muted);font-size:.75rem}
.switch{display:flex;align-items:center;gap:9px;color:#c6d7df;font-size:.82rem;font-weight:800;cursor:pointer}.switch input{position:absolute;opacity:0}.switch span{width:42px;height:24px;border-radius:999px;background:#3c5260;padding:3px;transition:.2s}.switch span:before{content:"";display:block;width:18px;height:18px;border-radius:50%;background:#fff;transition:.2s}.switch input:checked+span{background:var(--green)}.switch input:checked+span:before{transform:translateX(18px)}.bit-summary{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin:22px 0}.bit-summary div{padding:13px;border-radius:12px;background:#081722;border:1px solid #29495b}.bit-summary strong{font-size:1.35rem}.binary-row{display:grid;grid-template-columns:100px 1fr;align-items:center;gap:12px;margin:10px 0}.binary-label{color:#92a8b4;font-size:.78rem;font-weight:850}.bits{display:grid;grid-template-columns:repeat(35,minmax(10px,1fr));gap:3px;align-items:center}.bit{height:34px;display:grid;place-items:center;border-radius:5px;font:800 .75rem/1 ui-monospace,SFMono-Regular,Consolas,monospace}.dot{color:#577080;text-align:center}.boundary{position:relative}.boundary:after{content:"";position:absolute;right:-4px;top:-8px;bottom:-8px;width:3px;background:var(--red);border-radius:99px;box-shadow:0 0 0 3px #da121a18}.boundary-caption{text-align:center;color:#ff8b98;font-size:.78rem;font-weight:850;margin-top:15px}.decimal-boundary{display:flex;border:1px solid #29495b;border-radius:14px;overflow:hidden;min-height:64px}.decimal-boundary div{display:grid;place-items:center;text-align:center;padding:12px;font-weight:850}.decimal-boundary .net{background:#0d5e2d}.decimal-boundary .borrow{background:#a78f05;color:#08131f}.decimal-boundary .host{background:#304957}.teaching-note{padding:14px 16px;margin:22px 0 0;border-left:4px solid var(--yellow);background:#0a1925;color:#c7d8df;border-radius:0 12px 12px 0}
.subnets-card .section-head>span{color:var(--muted);font-size:.78rem}.subnet-list{display:grid;gap:9px;margin-top:20px}.subnet-row{display:grid;grid-template-columns:54px 1fr 1fr 1fr;gap:12px;align-items:center;padding:13px 15px;border:1px solid #29495b;background:#081722;border-radius:13px}.subnet-row.current{border-color:var(--yellow);box-shadow:inset 4px 0 0 var(--yellow)}.subnet-row b{color:#79909d;font-size:.78rem}.subnet-row span{font:750 .82rem/1.3 ui-monospace,SFMono-Regular,Consolas,monospace}.subnet-row small{display:block;color:#758c99;font:600 .68rem/1.3 Inter,system-ui,sans-serif;margin-bottom:3px}.ellipsis{text-align:center;color:#78909e;padding:4px}footer{display:flex;justify-content:space-between;gap:20px;border-top:1px solid var(--line);padding:26px 0 38px;color:#78909e;font-size:.8rem}
@media(max-width:1100px){.workspace{grid-template-columns:1fr}.controls-card{position:static}.controls-card form{display:grid;grid-template-columns:1fr 1fr;gap:0 24px}.quick-scenarios,.legend,.error{grid-column:1/-1}.metric-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:760px){main,footer{width:min(100% - 28px,1440px)}.topbar{position:relative;padding:13px 14px}.header-actions a{display:none}.intro{display:block;padding:36px 0 28px}.intro>p{margin-top:18px}.intro h1{font-size:2.8rem}.workspace{gap:14px}.controls-card form{display:block}.summary-card,.boundary-card,.subnets-card,.controls-card{padding:20px;border-radius:19px}.metric-grid{grid-template-columns:1fr 1fr}.bit-summary{grid-template-columns:1fr 1fr}.binary-row{display:block}.binary-label{display:block;margin-bottom:7px}.bits{overflow-x:auto;grid-template-columns:repeat(35,22px);padding:6px 0}.subnet-row{grid-template-columns:42px 1fr}.subnet-row span:nth-child(3),.subnet-row span:nth-child(4){display:none}.section-head{display:block}.section-head>.valid-badge,.section-head>.switch,.section-head>span{display:inline-flex;margin-top:12px}footer{display:block}footer span{display:block;margin-top:5px}}
@media(max-width:480px){.metric-grid{grid-template-columns:1fr}.intro h1{font-size:2.35rem}}