:root{--blue:#1463d8;--blue2:#0b3f91;--navy:#061a33;--green:#168654;--orange:#d97706;--red:#b42318;--text:#172033;--muted:#64748b;--line:#dce6f2;--bg:#f5f8fc;--white:#fff;--shadow:0 18px 45px rgba(12,45,85,.12)}
    *{box-sizing:border-box}html{scroll-behavior:smooth;overflow-x:clip;-webkit-text-size-adjust:100%}body{margin:0;overflow-x:clip;font-family:Inter,"Segoe UI",Roboto,Arial,sans-serif;color:var(--text);background:var(--bg);line-height:1.68}a{color:inherit;text-decoration:none}.container{width:92%;max-width:1180px;min-width:0;margin:0 auto}.header{position:sticky;top:0;z-index:10;width:100%;background:rgba(255,255,255,.95);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}.nav{min-height:70px;display:flex;align-items:center;justify-content:space-between;gap:22px}.brand{display:flex;flex-direction:column;line-height:1.05}.brand strong{color:var(--blue);font-size:24px}.brand span{font-size:12px;margin-top:4px}.nav-links{display:flex;gap:22px;font-size:14px;font-weight:800}.nav-links a:hover,.active{color:var(--blue)}
    .hero{width:100%;color:#fff;background:radial-gradient(circle at 75% 20%,rgba(48,145,255,.25),transparent 28%),linear-gradient(135deg,#041429,#06264c 58%,#031222);padding:70px 0 58px}.breadcrumb{font-size:14px;color:#c9dcf8;margin-bottom:14px;overflow-wrap:anywhere}.breadcrumb a:hover{color:#fff}.hero h1{max-width:980px;margin:0 0 16px;font-size:clamp(36px,5.5vw,62px);line-height:1.08;letter-spacing:-1.8px;overflow-wrap:anywhere}.hero p{max-width:850px;margin:0;color:#d9e8ff;font-size:19px}.article-wrap{display:grid;grid-template-columns:minmax(0,1fr) 290px;gap:34px;align-items:start;min-width:0;max-width:100%;padding:42px 0 70px}.article{min-width:0;max-width:100%;background:#fff;border:1px solid var(--line);border-radius:16px;padding:clamp(24px,4vw,48px);box-shadow:var(--shadow)}.article h2{font-size:30px;line-height:1.25;margin:42px 0 14px;color:#10223d}.article h2:first-child{margin-top:0}.article h3{font-size:20px;margin:24px 0 8px}.article p{margin:0 0 17px;color:#344258}.article p,.article li,.note{overflow-wrap:break-word}.article li{margin:7px 0;color:#344258}.article strong{color:#172033}
    .author-card{margin:0 0 28px;overflow:hidden;border:1px solid #cbdced;border-radius:14px;background:linear-gradient(135deg,#f8fbff,#fff);box-shadow:0 8px 22px rgba(10,40,80,.07)}.author-profile{display:flex;align-items:center;gap:15px;padding:18px 20px 12px}.author-avatar{display:grid;place-items:center;flex:0 0 54px;width:54px;height:54px;border-radius:50%;background:linear-gradient(135deg,var(--blue2),var(--blue));color:#fff;font-size:17px;font-weight:900;box-shadow:0 6px 14px rgba(20,99,216,.22)}.author-details{min-width:0;line-height:1.35}.author-details h2{margin:0 0 2px;font-size:20px;color:var(--blue2)}.author-title{display:block;color:#25364d;font-size:14px;font-weight:800}.author-expertise{display:block;margin-top:2px;color:var(--muted);font-size:12px}.author-bio{margin:0!important;padding:0 20px 16px;color:#475569!important;font-size:14px!important;line-height:1.55}.author-actions{display:flex;flex-wrap:wrap;gap:8px;padding:12px 20px;border-top:1px solid var(--line);background:#f3f8fe}.author-actions a,.author-actions span{display:inline-flex;align-items:center;gap:6px;padding:7px 10px;border-radius:7px;color:var(--blue2);font-size:12px;font-weight:900}.author-actions a:hover{background:#e2edfb;color:var(--blue)}.author-actions .is-disabled{color:#8a98aa;cursor:not-allowed}
    .hero-image,.article-figure{max-width:100%;margin:26px 0 32px}.hero-image img,.article-figure img{display:block;width:100%;height:auto;border-radius:13px;border:1px solid var(--line)}figcaption{font-size:13px;color:var(--muted);margin-top:9px}.quick{border:1px solid #b9d0ee;border-left:4px solid var(--green);border-radius:12px;background:#f7fbff;padding:18px 20px;margin:26px 0}.quick h2{font-size:21px;margin:0 0 10px}.quick ul{margin:0;padding-left:22px}.warning{border-left:4px solid var(--orange);background:#fff7ed;border-radius:10px;padding:17px 18px;margin:18px 0}.warning h3{margin:0 0 6px}.grid{display:grid;grid-template-columns:1fr 1fr;gap:16px;min-width:0;margin:20px 0}.card{min-width:0;border:1px solid var(--line);background:#f8fbff;border-radius:12px;padding:18px}.card h3{margin:0 0 8px;color:var(--blue2)}.table-wrap{width:100%;max-width:100%;min-width:0;overflow-x:auto;border:1px solid var(--line);border-radius:12px;margin:20px 0;-webkit-overflow-scrolling:touch}table{width:100%;border-collapse:collapse;min-width:720px}th,td{padding:12px 14px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}th{background:#edf5ff;text-transform:uppercase;font-size:12px;color:#14223a}tr:last-child td{border-bottom:0}.up{color:var(--red);font-weight:900}.down{color:var(--green);font-weight:900}.mixed{color:var(--orange);font-weight:900}.note{border-left:4px solid var(--blue);background:#f7fbff;padding:16px 18px;border-radius:10px;margin:22px 0}.formula{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin:20px 0;padding:18px;border-radius:12px;background:#061a33;color:#fff;font-weight:800}.formula span{padding:7px 10px;border-radius:7px;background:#12365e}.formula b{color:#7fc4ff}.related{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:20px}.related a{padding:15px 17px;border:1px solid var(--line);border-radius:10px;background:#f8fbff;color:var(--blue2);font-weight:800}.related a:hover{border-color:#8db7ed;background:#edf5ff}
    .size-visual{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin:26px 0 32px}.size-box{min-height:190px;border:1px solid var(--line);border-radius:13px;background:linear-gradient(135deg,#edf5ff,#fff);padding:18px;display:grid;align-content:space-between;overflow:hidden}.size-box h3{margin:0;color:var(--blue2)}.particle-row{display:flex;align-items:center;justify-content:center;gap:8px;min-height:72px}.dot{display:block;border-radius:50%;background:#8b5e34;box-shadow:inset -4px -5px 0 rgba(0,0,0,.14)}.dot.small{width:12px;height:12px}.dot.mid{width:26px;height:26px}.dot.large{width:44px;height:44px}.dot.xlarge{width:60px;height:60px}.size-box p{font-size:13px;margin:0;color:#475569}.side-card{position:-webkit-sticky;position:sticky;top:86px;align-self:start;max-height:calc(100vh - 102px);min-width:0;overflow-y:auto;overscroll-behavior:contain;background:#fff;border:1px solid var(--line);border-radius:14px;padding:22px;box-shadow:0 8px 24px rgba(10,40,80,.06);scrollbar-width:thin;scrollbar-color:#b9cce4 transparent}.side-card h2{font-size:18px;margin:0 0 12px}.side-card a{display:block;padding:9px 0;border-top:1px solid #edf2f8;color:var(--blue2);font-weight:800;font-size:13px}.side-card a:hover{color:var(--blue)}.footer{width:100%;background:var(--navy);color:#d9e8ff;padding:28px 0}.footer .container{display:flex;justify-content:space-between;gap:20px}.footer a{color:#fff;font-weight:800}
    .faq-list{margin:20px 0 10px;border-top:1px solid var(--line)}.faq-item{border-bottom:1px solid var(--line);background:#fff}.faq-item summary{position:relative;padding:18px 44px 18px 4px;color:var(--blue2);font-size:17px;font-weight:900;cursor:pointer;list-style:none}.faq-item summary::-webkit-details-marker{display:none}.faq-item summary:after{content:"+";position:absolute;right:10px;top:50%;translate:0 -50%;font-size:24px;color:var(--blue)}.faq-item[open] summary:after{content:"-";}.faq-item p{padding:0 40px 18px 4px;margin:0;color:#475569}
    @media(max-width:900px){.article-wrap{grid-template-columns:minmax(0,1fr)}.side-card{position:static}.nav-links{display:none}.size-visual{grid-template-columns:1fr}}@media(max-width:640px){.nav{min-height:70px}.brand{min-width:0;max-width:100%}.brand strong{font-size:22px}.hero{padding:44px 0}.breadcrumb{font-size:13px;line-height:1.55}.hero h1{font-size:34px;line-height:1.12;letter-spacing:0}.hero p{font-size:16px;line-height:1.55}.article-wrap{display:block;width:92%;max-width:100%;padding:28px 0 44px}.article{width:100%;max-width:100%;overflow:hidden;border-radius:12px;padding:24px 18px}.article h2{font-size:23px}.article h3{font-size:18px}.article p,.article li{font-size:16px}.grid,.related{display:block;width:100%;max-width:100%}.card+.card,.related a+a{margin-top:12px}.related a{display:block}.table-wrap{display:block;width:100%;max-width:100%;overflow-x:auto}table{width:100%;min-width:720px}.author-profile{align-items:flex-start;padding:16px 16px 10px}.author-avatar{flex-basis:46px;width:46px;height:46px;font-size:15px}.author-details h2{font-size:18px}.author-expertise{font-size:11px}.author-bio{padding:0 16px 14px;font-size:13px!important}.author-actions{padding:10px 12px}.side-card{display:none}.footer .container{flex-direction:column}}
/* PFD/P&ID components */
.drawing-compare{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:26px 0 32px}.diagram-card{border:1px solid var(--line);border-radius:13px;background:#f8fbff;padding:18px}.diagram-card h3{margin:0 0 12px;color:var(--blue2)}.diagram-card img{display:block;width:100%;height:auto;border-radius:11px;border:1px solid #cfe0f5;background:#fff}.btn{display:inline-flex;align-items:center;justify-content:center;border-radius:9px;border:1px solid #b9d0ee;background:#fff;color:var(--blue2);padding:11px 18px;font-weight:800;font-size:14px;margin-top:10px}.btn-primary{border-color:transparent;background:linear-gradient(135deg,#1672f3,#0e52be);color:#fff;box-shadow:0 8px 22px rgba(20,99,216,.26)}
/* Troubleshooting components */
.zoom-link{display:block;position:relative;max-width:100%;border-radius:13px;overflow:hidden;background:#eef4fb}.zoom-link:after{content:"Click to enlarge";position:absolute;right:12px;bottom:12px;padding:7px 10px;border-radius:7px;background:rgba(6,26,51,.88);color:#fff;font-size:12px;font-weight:800;opacity:0;transition:opacity .2s}.zoom-link:hover:after,.zoom-link:focus:after{opacity:1}.steps{counter-reset:step;list-style:none;padding:0}.steps li{position:relative;padding:0 0 18px 48px}.steps li:before{counter-increment:step;content:counter(step);position:absolute;left:0;top:1px;width:32px;height:32px;display:grid;place-items:center;border-radius:50%;background:var(--blue);color:#fff;font-weight:900}.faq{border-top:1px solid var(--line);padding:18px 0}.faq h3{margin:0 0 7px}
/* Fuel-property components */
.byline{display:flex;align-items:center;gap:10px;min-height:68px;margin:0 0 22px;padding:6px 14px;border:1px solid var(--line);border-radius:10px;background:#f8fbff}.author-mark{display:grid;place-items:center;flex:0 0 40px;width:40px;height:40px;border-radius:50%;background:var(--blue2);color:#fff;font-size:14px;font-weight:900}.byline-text{line-height:1.15}.byline-label{display:block;color:var(--muted);font-size:10px;font-weight:800;text-transform:uppercase;letter-spacing:.04em}.author-name{display:block;margin:1px 0;color:var(--blue2);font-size:15px;font-weight:900}.author-role{display:block;color:#344258;font-size:11px}.image-placeholder{display:grid;place-items:center;min-height:360px;padding:32px;border:2px dashed #9eb9d8;border-radius:13px;background:linear-gradient(135deg,#edf5ff,#f8fbff);text-align:center;color:var(--blue2)}.image-placeholder strong{display:block;font-size:22px;color:var(--blue2)}.image-placeholder span{display:block;margin-top:8px;font-size:13px;color:var(--muted);overflow-wrap:anywhere}
/* CFD components */
.article-figure.is-narrow{max-width:610px;margin-left:auto;margin-right:auto}.figure-gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px;margin:26px 0 32px}.figure-gallery .article-figure{min-width:0;margin:0}.figure-gallery .article-figure img{width:100%;height:auto}.flow{display:grid;grid-template-columns:1fr auto 1fr auto 1fr;gap:10px;align-items:center;margin:26px 0;padding:22px;border-radius:14px;background:#061a33;color:#fff}.flow-step{height:100%;padding:15px;border:1px solid #31577f;border-radius:10px;background:#0e3158;text-align:center}.flow-step strong{display:block;color:#fff}.flow-step span{display:block;margin-top:4px;color:#c9dcf8;font-size:12px}.flow-arrow{color:#70d6a5;font-size:23px;font-weight:900}.result-band{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:24px 0}.result{padding:20px 14px;border:1px solid #cfe3d8;border-radius:12px;background:#f2fbf6;text-align:center}.result strong{display:block;color:var(--green);font-size:30px;line-height:1.1}.result span{display:block;margin-top:7px;color:#405268;font-size:13px}
/* Shared FAQ accordion */
.faq-list{margin:20px 0 10px;border-top:1px solid var(--line)}.faq-item{border-bottom:1px solid var(--line);background:#fff}.faq-item summary{position:relative;padding:18px 44px 18px 4px;color:var(--blue2);font-size:17px;font-weight:900;cursor:pointer;list-style:none}.faq-item summary::-webkit-details-marker{display:none}.faq-item summary:after{content:"+";position:absolute;right:10px;top:50%;translate:0 -50%;font-size:24px;color:var(--blue)}.faq-item[open] summary:after{content:"−"}.faq-item p{padding:0 40px 18px 4px;margin:0;color:#475569}
@media(max-width:900px){.drawing-compare{grid-template-columns:1fr}.flow{grid-template-columns:1fr}.flow-arrow{transform:rotate(90deg);text-align:center}.result-band{grid-template-columns:1fr}}
@media(max-width:640px){.image-placeholder{min-height:240px;padding:20px}.hero-image,.article-figure,.zoom-link{width:100%;max-width:100%}.figure-gallery{grid-template-columns:1fr}}