:root{--ink:#0b1220;--navy:#0a1a33;--deep:#06101f;--steel:#22324a;--ice:#7cc6ff;--cool:#3d8bfd;--copper:#ff7a2f;--ember:#e8432a;--cream:#fff7ef;--muted:#5b6678;--line:#e7e1d9;--paper:#fbf8f4}
*{box-sizing:border-box}html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;font:17px/1.65 ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;color:var(--ink);background:var(--paper)}
a{color:#b33a12}h1,h2,h3{line-height:1.08;letter-spacing:-.02em;margin:0 0 .5em}
h2{font-size:clamp(2rem,4.6vw,3.4rem);font-weight:900}h3{font-size:1.2rem;font-weight:800}
.serif{font-family:ui-serif,Georgia,"Times New Roman",serif;font-style:italic;font-weight:400;letter-spacing:-.01em}
.wrap{max-width:1180px;margin:0 auto;padding:0 22px}
.eyebrow{font:700 .78rem/1 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;letter-spacing:.18em;text-transform:uppercase;color:var(--copper);margin:0 0 14px}
.btn{display:inline-block;border:0;cursor:pointer;font-family:inherit;font-weight:800;font-size:1.02rem;line-height:1;padding:16px 22px;border-radius:999px;text-decoration:none;transition:transform .15s}
.btn:hover{transform:translateY(-2px)}.hot{background:linear-gradient(90deg,var(--ember),var(--copper));color:#fff;box-shadow:0 10px 30px -10px rgba(232,67,42,.7)}
.ghost{background:transparent;color:inherit;border:2px solid currentColor}
/* header */
.top{position:absolute;inset:0 0 auto;z-index:5}.top .wrap{display:flex;justify-content:space-between;align-items:center;padding-top:18px}
.logo{color:#fff;text-decoration:none;font-weight:900;letter-spacing:-.02em;display:flex;gap:10px;align-items:center;font-size:1.05rem}
.logo i{width:30px;height:30px;border-radius:50%;background:conic-gradient(from 200deg,var(--cool),var(--copper),var(--ember),var(--cool));display:block}
.top .btn{padding:11px 18px;font-size:.92rem}
/* hero */
.hero{position:relative;color:#fff;background:radial-gradient(1200px 600px at 85% 110%,rgba(255,122,47,.55),transparent 60%),radial-gradient(900px 500px at 0% 0%,rgba(61,139,253,.35),transparent 60%),linear-gradient(160deg,var(--deep),var(--navy) 55%,#2a1430);overflow:hidden;padding:110px 0 70px}
.hero:after{content:"";position:absolute;inset:auto 0 0;height:8px;background:linear-gradient(90deg,var(--cool),var(--ice),var(--copper),var(--ember))}
.hero .wrap{display:grid;grid-template-columns:1.2fr .9fr;gap:48px;align-items:center}
.hero h1{font-size:clamp(2.7rem,7.2vw,5.6rem);font-weight:950;line-height:.92;letter-spacing:-.045em;margin:0 0 22px}
.hero h1 .hot-t{background:linear-gradient(90deg,#ffd0a8,var(--copper),var(--ember));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero h1 small{display:block;font-size:.34em;letter-spacing:-.01em;font-weight:700;color:#b9c9e0;margin-top:14px;line-height:1.2}
.hero .lede{font-size:1.15rem;color:#d4deec;max-width:560px}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:22px 0 0;padding:0;list-style:none}.chips li{border:1px solid rgba(255,255,255,.22);border-radius:999px;padding:6px 12px;font-size:.86rem;color:#e6edf7;background:rgba(255,255,255,.05)}
.lead{background:var(--cream);color:var(--ink);border-radius:24px;padding:26px;box-shadow:0 40px 80px -30px rgba(0,0,0,.6);position:relative}
.lead:before{content:"";position:absolute;inset:-2px;border-radius:26px;background:linear-gradient(140deg,var(--cool),var(--copper));z-index:-1}
.ftitle{font-weight:900;font-size:1.45rem;margin:0;letter-spacing:-.02em}.fsub{margin:2px 0 12px;color:var(--muted);font-size:.92rem}
.lead label{display:block;font-weight:700;font-size:.86rem;margin:0 0 10px}
.lead input,.lead textarea,.lead select{display:block;width:100%;margin-top:4px;font:inherit;font-size:1rem;padding:12px 14px;border:1.5px solid #d8cfc4;border-radius:12px;background:#fff}
.lead input:focus,.lead textarea:focus,.lead select:focus{outline:3px solid rgba(61,139,253,.35);border-color:var(--cool)}
.lead .btn{width:100%;margin-top:6px;font-size:1.1rem}.opt summary{cursor:pointer;font-weight:700;font-size:.88rem;color:#2856a8;margin:0 0 10px}
.fine{font-size:.78rem;color:var(--muted);margin:10px 0 0;text-align:center}.hp{position:absolute;left:-9999px}
/* temperature band */
.band{background:var(--deep);color:#dbe6f5;padding:28px 0}.band .wrap{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.band b{display:block;font-size:2.2rem;font-weight:950;letter-spacing:-.04em;color:#fff;line-height:1}.band span{font-size:.88rem}
.band div{border-left:3px solid;padding-left:14px}.band div:nth-child(1){border-color:var(--cool)}.band div:nth-child(2){border-color:var(--ice)}.band div:nth-child(3){border-color:var(--copper)}.band div:nth-child(4){border-color:var(--ember)}
section{padding:96px 0}.split{display:grid;grid-template-columns:1fr 1fr;gap:56px;align-items:start}
.intro p{font-size:1.08rem}.big{font-size:clamp(1.25rem,2.2vw,1.6rem);line-height:1.4;font-weight:600;letter-spacing:-.01em}
/* quiz */
.dark{background:linear-gradient(180deg,var(--navy),var(--deep));color:#e3ebf6}.dark h2{color:#fff}.dark a{color:#ffb98c}
.quiz{display:grid;grid-template-columns:70px 1fr;gap:28px;background:rgba(255,255,255,.04);border:1px solid rgba(255,255,255,.12);border-radius:28px;padding:34px;margin-top:30px}
.thermo{width:34px;height:300px;border-radius:20px;background:#0d1d36;border:3px solid #5d7393;position:relative;margin:0 auto;overflow:hidden}
.merc{position:absolute;bottom:0;left:0;right:0;height:12%;background:linear-gradient(0deg,var(--cool),var(--copper),var(--ember));transition:height .6s cubic-bezier(.2,.8,.2,1)}
.qn{font:700 .75rem/1 ui-monospace,Menlo,monospace;letter-spacing:.16em;text-transform:uppercase;color:var(--ice)}
.quiz h3{font-size:clamp(1.5rem,3vw,2.2rem);color:#fff}.opts{display:flex;flex-wrap:wrap;gap:10px}
.opt{font:inherit;font-weight:700;padding:14px 18px;border-radius:14px;border:1.5px solid rgba(255,255,255,.25);background:rgba(255,255,255,.06);color:#fff;cursor:pointer}
.opt:hover,.opt:focus{background:var(--copper);border-color:var(--copper);outline:none}
/* cutaway */
.cut{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:center}
.tank{width:100%;max-width:420px;display:block;margin:0 auto}
.spot{cursor:pointer}.spot circle{fill:#fff}.spot .ring{fill:rgba(255,255,255,.18);stroke:#fff;stroke-width:2;animation:pulse 2s infinite;transform-origin:center;transform-box:fill-box}
.spot.on circle:not(.ring){fill:var(--ice)}.spot:focus{outline:none}.spot:focus .ring{stroke:var(--ice);stroke-width:4}
@keyframes pulse{50%{transform:scale(1.25);opacity:.5}}
.flame{animation:fl 1.2s ease-in-out infinite alternate}@keyframes fl{to{transform:translateY(-3px);opacity:.75}}
.bubbles circle{fill:rgba(255,255,255,.55);animation:up 4s linear infinite}.bubbles circle:nth-child(2){animation-delay:1s}.bubbles circle:nth-child(3){animation-delay:2s}.bubbles circle:nth-child(4){animation-delay:3s}
@keyframes up{to{transform:translateY(-110px);opacity:0}}
.spotinfo{background:#fff;border:1px solid var(--line);border-radius:20px;padding:24px;box-shadow:0 20px 40px -25px rgba(10,26,51,.4)}
.spotlist{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 18px}.spotlist button{font:inherit;font-size:.88rem;font-weight:700;border:1.5px solid var(--line);background:#fff;border-radius:999px;padding:8px 14px;cursor:pointer}
.spotlist button.on{background:var(--navy);color:#fff;border-color:var(--navy)}
/* cards */
.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:28px}
.card{background:#fff;border:1px solid var(--line);border-radius:22px;padding:24px}.card .n{font:800 .8rem ui-monospace,monospace;color:var(--copper)}
/* compare toggle */
.seg{display:inline-flex;background:#ece6de;border-radius:999px;padding:5px;margin:8px 0 22px;flex-wrap:wrap}.seg button{font:inherit;font-weight:800;border:0;background:transparent;padding:11px 18px;border-radius:999px;cursor:pointer;color:var(--ink)}
.seg button[aria-selected=true]{background:var(--navy);color:#fff}
.pane{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}.pane div{background:#fff;border-radius:18px;padding:18px 20px;border:1px solid var(--line)}.pane b{display:block;font-size:.78rem;letter-spacing:.12em;text-transform:uppercase;color:var(--muted)}
/* calculator */
.calc{background:#fff;border-radius:24px;padding:28px;color:var(--ink)}.calc label{display:block;font-weight:700;margin:12px 0 4px}
.calc input[type=range]{width:100%;accent-color:var(--copper)}.out{display:flex;gap:18px;margin-top:18px;flex-wrap:wrap}
.out div{flex:1;min-width:140px;background:var(--paper);border-radius:16px;padding:14px 16px}.out b{display:block;font-size:2rem;font-weight:950;letter-spacing:-.03em}
.ctaband{background:linear-gradient(100deg,var(--cool),#6b4bd6 45%,var(--ember));color:#fff;padding:64px 0;text-align:center}.ctaband h2{color:#fff}
.ctaband .btn{background:#fff;color:var(--ember)}
.steps{counter-reset:s;list-style:none;padding:0;margin:26px 0 0;display:grid;grid-template-columns:repeat(5,1fr);gap:14px}
.steps li{counter-increment:s;background:#fff;border-radius:20px;padding:22px;border-top:5px solid var(--copper)}.steps li:before{content:"0" counter(s);font-weight:900;font-size:2rem;line-height:1;color:#e7ddd2;display:block;margin-bottom:8px}
.faq{border-bottom:1px solid var(--line);padding:4px 0}.faq summary{cursor:pointer;list-style:none;padding:16px 40px 16px 0;position:relative}.faq summary::-webkit-details-marker{display:none}
.faq summary h3{margin:0;font-size:1.12rem}.faq summary:after{content:"+";position:absolute;right:6px;top:10px;font-size:1.6rem;color:var(--copper)}
.faq[open] summary:after{content:"–"}.faq div{padding:0 0 18px;color:#2a3344}
.areas{display:flex;flex-wrap:wrap;gap:10px;list-style:none;padding:0}.areas li{background:#fff;border:1px solid var(--line);border-radius:999px;padding:8px 16px;font-weight:700}
.cite{text-decoration:none;font-size:.72em;color:#2856a8}.srcs li{margin-bottom:6px;font-size:.9rem;word-break:break-word}
.soon{color:var(--muted);font-size:.92rem}
footer{background:var(--deep);color:#9fb0c8;padding:46px 0 110px;font-size:.9rem}footer a{color:#cfe0f7}
.mcta{display:none}
@media (max-width:900px){.hero{padding:86px 0 48px}.hero .wrap,.split,.cut{grid-template-columns:1fr;gap:30px}.band .wrap{grid-template-columns:1fr 1fr}
.cards,.steps{grid-template-columns:1fr 1fr}.pane{grid-template-columns:1fr}section{padding:64px 0}.top .btn{display:none}
.quiz{grid-template-columns:1fr;padding:22px}.thermo{width:100%;height:18px}.merc{height:100%!important;width:var(--w,12%);right:auto;transition:width .6s}
.mcta{display:block;position:fixed;left:12px;right:12px;bottom:12px;z-index:20;text-align:center;box-shadow:0 12px 30px -8px rgba(0,0,0,.5)}}
@media (max-width:520px){.cards,.steps{grid-template-columns:1fr}.hero h1{font-size:2.6rem}}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}html{scroll-behavior:auto}}

.top .wrap{gap:18px}.mainnav{display:flex;gap:18px;list-style:none;margin:0 0 0 auto;padding:0}.mainnav a{color:#d4deec;text-decoration:none;font-weight:700;font-size:.92rem}.mainnav a:hover,.mainnav a[aria-current]{color:#fff;text-decoration:underline;text-underline-offset:5px;text-decoration-color:var(--copper)}
.menu{display:none;margin-left:auto;position:relative}.menu summary{list-style:none;cursor:pointer;color:#fff;font-weight:800;border:1.5px solid rgba(255,255,255,.4);border-radius:999px;padding:8px 14px}.menu summary::-webkit-details-marker{display:none}
.menu ul{position:absolute;right:0;top:46px;background:var(--deep);border:1px solid #2b3d5a;border-radius:16px;list-style:none;margin:0;padding:10px;min-width:230px;z-index:30}.menu li a{display:block;color:#fff;text-decoration:none;padding:10px 12px;font-weight:700}
.crumbs{font-size:.84rem;color:#9fb0c8;margin:0 0 12px}.crumbs a{color:#cfe0f7}
.art{max-width:300px;width:100%;display:block;margin:0 auto 20px}
.flinks{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:6px 22px;list-style:none;padding:0;margin:0 0 24px}
.prose h2{margin-top:1.2em;font-size:clamp(1.6rem,3vw,2.2rem)}.prose{max-width:820px}
.tbl{width:100%;border-collapse:collapse;background:#fff;border-radius:16px;overflow:hidden;font-size:.95rem}.tbl th,.tbl td{padding:12px 14px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}.tbl th{background:var(--navy);color:#fff}
.callout{background:#fff4ec;border-left:5px solid var(--ember);border-radius:14px;padding:18px 20px;margin:18px 0;color:var(--ink)}
.linkcards{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px}.linkcards a{display:block;background:#fff;border:1px solid var(--line);border-radius:20px;padding:22px;text-decoration:none;color:var(--ink)}.linkcards a:hover{border-color:var(--copper)}.linkcards b{display:block;font-size:1.15rem;margin-bottom:6px}
.pane[hidden],[hidden]{display:none!important}
.dcard{background:#0f2240!important;border-color:#2b3d5a!important;color:#e3ebf6}.dcard h3{color:#fff}
@media (max-width:900px){.hero{padding-top:78px}.hero .wrap{gap:14px}.hero .wrap>div:first-child{display:contents}.hero .lead{order:2;margin:6px 0 4px}.hero .lede,.hero .chips{order:3}.hero h1{font-size:2.3rem;margin-bottom:6px}.hero h1 small{font-size:.95rem;margin-top:8px}.hero .eyebrow{margin-bottom:6px}.crumbs{margin-bottom:4px}}
@media (max-width:1000px){.mainnav{display:none}.menu{display:block}.top .btn{display:none}}
@media (max-width:600px){.tbl{font-size:.85rem}.tbl th,.tbl td{padding:8px}}