.zsa-th-header {position:relative;margin-bottom:28px;}
.zsa-th-topline {display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px;padding:0 0 20px;border-bottom:1px solid #dde4ed;}
.zsa-th-identity {display:flex;align-items:center;gap:12px;min-width:0;flex:1 1 400px;}
.metals .zsa-th-brand {display:inline-flex;align-items:center;flex-shrink:0;min-height:52px;min-width:52px;text-decoration:none;color:var(--zsa-navy);}
.zsa-th-brand img {display:block;flex-shrink:0;}
.zsa-th-header-tools {display:flex;align-items:center;justify-content:flex-end;flex-wrap:wrap;gap:16px;max-width:100%;margin-left:auto;}
.zsa-th-header-buttons {display:flex;align-items:center;gap:8px;}
.metals .zsa-th-share-toggle {display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:9px 12px;min-height:44px;background:white;}
.zsa-th-icon {width:18px;height:18px;flex-shrink:0;}
.zsa-th-instructions-open {flex-shrink:0;}
.metals h1 {min-width:0;font-size:clamp(1.6rem,1.2rem + 1.2vw,2rem);letter-spacing:-.035em;line-height:1.15;margin:0;font-weight:650;}
.zsa-th-lede {color:var(--zsa-navy);font-size:clamp(1.05rem,1rem + .3vw,1.2rem);font-weight:500;}
.zsa-th-share-panel {margin-top:14px;padding:20px;border:1px solid #cdd9e9;border-radius:12px;background:white;box-shadow:0 7px 20px rgba(11,42,91,.06);}
.zsa-th-share-heading {display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:5px;}
.zsa-th-share-heading h2 {font-size:18px;font-weight:600;}
.metals .zsa-th-icon-button {display:inline-flex;align-items:center;justify-content:center;min-width:44px;min-height:44px;border:1px solid #d5deea;border-radius:8px;background:#f7f9fc;color:#425a7b;font-size:24px;padding:0;line-height:1;}
.metals .zsa-th-fullscreen-toggle {width:46px;min-width:46px;height:46px;min-height:46px;flex-shrink:0;background:white;}
.metals .zsa-th-fullscreen-toggle[hidden] {display:none;}
.zsa-th-fullscreen-toggle[aria-pressed="true"] {background:#edf4ff;border-color:#194d9d;}
.metals .zsa-th-fullscreen-status {margin-top:12px;}
.zsa-th-share-label {display:block;margin:14px 0 6px;font-size:12px;font-weight:600;color:#536075;}
.zsa-th-share-link {display:flex;gap:8px;align-items:stretch;}
.zsa-th-share-link input {display:block;flex:1 1 200px;min-width:0;min-height:46px;width:100%;border:1px solid #b8c8dc;border-radius:8px;padding:9px 11px;background:#f8fafd;color:#334e72;font-size:13px;}
.zsa-th-share-options {display:flex;flex-wrap:wrap;align-items:center;gap:7px;margin-top:12px;}
.zsa-th-share-options a {display:inline-flex;align-items:center;justify-content:center;gap:7px;min-width:44px;min-height:44px;padding:8px 12px;border:1px solid #d8e1ed;border-radius:8px;color:#355579;font-size:13px;text-decoration:none;background:white;}
.zsa-th-share-options a:hover {background:#f0f5fd;}
.zsa-th-share-status {min-height:21px;margin-top:10px!important;font-size:12px;color:#38623e;}
.zsa-th-instructions {width:calc(100% - 32px);max-width:720px;max-height:85vh;overflow:auto;padding:24px;border:1px solid #c5d3e4;border-radius:15px;background:white;color:var(--zsa-slate);box-shadow:0 18px 60px rgba(11,42,91,.2);font-size:15px;line-height:1.6;}
.zsa-th-instructions::backdrop {background:rgba(11,27,51,.45);}
.zsa-th-instructions-heading {display:flex;align-items:flex-start;justify-content:space-between;gap:14px;margin-bottom:14px;}
.zsa-th-instructions-heading h2 {font-size:23px;line-height:1.25;font-weight:600;}
.zsa-th-instructions-heading button {flex-shrink:0;}
.zsa-th-instructions-steps {margin:18px 0;padding-left:23px;}
.zsa-th-instructions-steps li {padding-left:4px;margin:12px 0;}
.zsa-th-instructions-example {padding:15px 17px;border:1px solid #d6e2f2;border-radius:10px;background:#f5f8fd;}
.zsa-th-instructions-example-label {font-size:11px;letter-spacing:.06em;text-transform:uppercase;font-weight:600;color:#536782;}
.zsa-th-instructions-equation {margin:6px 0 13px!important;color:var(--zsa-navy);font-size:22px;line-height:1.5;}
.zsa-th-instructions-equation:last-child {margin-bottom:0!important;}
.zsa-th-instructions-equation sub,.zsa-th-instructions-steps sub {font-size:.7em;line-height:0;vertical-align:-.2em;}
.zsa-th-instructions-equation sup,.zsa-th-instructions-steps sup {font-size:.7em;line-height:0;vertical-align:.4em;}
.zsa-th-instructions-note {margin-top:16px!important;font-size:13px;color:#536075;}

body{background:#edf2f7}.optics{--zsa-max-width:1440px;max-width:1440px;padding:28px 32px;background:#f6f8fb;font-size:14px;color:#40546b}.optics [hidden]{display:none!important}.optics h1{font-size:clamp(1.3rem,1rem + 1vw,1.85rem);margin:0;font-weight:650;letter-spacing:-.04em}.optics h2,.optics h3{font-weight:600;letter-spacing:-.035em}.optics .zsa-th-header{margin:0}.optics .zsa-th-brand{background:white;border:1px solid #e0e8f0;border-radius:15px;padding:8px}.optics .zsa-th-identity{gap:15px}.optics .zsa-th-header-buttons .zsa-btn{font-size:13px;border-radius:9px;background:white;padding:9px 13px;border-color:#cad7e4;color:#274864}.intro{display:flex;align-items:center;justify-content:space-between;gap:24px;padding:25px 0}.eyebrow{font-size:10px!important;letter-spacing:.14em;font-weight:700;color:#536c82;margin:0 0 10px}.intro h2{font-size:30px;margin:0 0 6px}.intro p:last-child{margin:0;font-size:13px}.intro a{font-size:12px;white-space:nowrap;text-decoration:none;color:#42637d}.workspace{display:grid;grid-template-columns:260px minmax(0,1fr);gap:22px;align-items:start}.controls{display:grid;gap:15px}.control-card,.bench-card{background:white;border:1px solid #dce5ef;border-radius:14px;box-shadow:0 4px 18px #193d6508}.control-card{padding:19px}.mode-group{display:grid;gap:8px}.mode-group button{display:grid;gap:3px;text-align:left;background:#f5f8fb;border:1px solid #dce5ed;border-radius:8px;padding:11px;color:#40596c}.mode-group button[aria-pressed=true]{background:#eaf5f1;border-color:#79b1a4;color:#1e6659}.mode-group strong{font-size:12px;font-weight:650}.mode-group span{font-size:10px}.control-card label{display:block;font-size:12px;font-weight:600;color:#38566d;margin:10px 0 6px}.control-card select,.control-card input[type=number]{width:100%;font-size:13px;min-height:42px;border:1px solid #cbd9e3;border-radius:7px;padding:8px;color:#2e4c62;background:#fff}.index-note{font:11px ui-monospace,monospace;color:#5a7182;margin:5px 0 12px}.angle-heading{display:flex;align-items:center;justify-content:space-between;gap:8px}.angle-heading label{margin:0}.angle-heading output{font-size:23px;font-weight:600;color:#166b5d;font-variant-numeric:tabular-nums}.optics input[type=range]{width:100%;height:36px;accent-color:#187566;cursor:pointer}.range-labels{display:flex;justify-content:space-between;font-size:10px;color:#61768a;margin-bottom:15px}.optics .zsa-btn{font-size:12px;min-height:44px;padding:9px 12px;border-color:#cbd8e3;border-radius:8px}.optics button:disabled{opacity:.5;cursor:default}.control-card .zsa-btn{width:100%}.hint{font-size:11px;line-height:1.6;margin:8px 0 0;color:#577085}.bench-card{overflow:hidden}.bench-heading{padding:19px 22px;display:flex;align-items:center;justify-content:space-between;gap:12px}.bench-heading .eyebrow{margin-bottom:4px;font-size:9px!important}.bench-heading h3{font-size:20px;margin:0}.power-dot,.live-dot{display:inline-block;width:7px;height:7px;border-radius:50%;background:#db4c55;margin-right:7px}.scene{background:#142630;color:#b6ced6;position:relative}.scene-topline,.scene-bottom{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:12px 20px;font-size:9px;letter-spacing:.12em}.scene-topline{border-bottom:1px solid #334b57}.scene-bottom{background:#10242e;min-height:38px;font-size:8px}.scene-bottom span:first-child{color:#88d6bd;font-weight:650}.scene svg{display:block;width:100%;height:auto;touch-action:none}#laser,#protractor{cursor:grab;outline:none}#laser:active,#protractor:active{cursor:grabbing}#laser:focus-visible>rect:first-child,#protractor:focus-visible>circle:first-child{stroke:#fff;stroke-width:4}.bench-tools{display:flex;align-items:center;gap:14px;padding:14px 20px;flex-wrap:wrap;border-bottom:1px solid #e0e8ee}.bench-tools label{display:flex;align-items:center;gap:5px;font-size:11px;min-height:32px;cursor:pointer}.bench-tools input{width:15px;height:15px;accent-color:#187566}.reset{border:0;background:none;color:#527087;font-size:11px!important;margin-left:auto;min-height:44px}.readings{display:grid;grid-template-columns:repeat(3,1fr);padding:18px 22px;gap:16px}.readings>div+div{border-left:1px solid #e0e8ef;padding-left:20px}.readings span{display:block;font-size:9px;letter-spacing:.12em;color:#5a7082;margin-bottom:4px}.readings strong{font-size:24px;font-weight:550;color:#163f59;font-variant-numeric:tabular-nums}.explanation{display:flex;align-items:baseline;gap:9px;padding:0 22px 17px}.explanation p{font-size:12px;line-height:1.7;margin:0}.live-dot{background:#278370;flex:0 0 6px;margin:0}.model-note{margin-top:24px;border:1px solid #dce5ed;padding:15px 20px;border-radius:10px;font-size:12px;background:white}.model-note summary{cursor:pointer;color:#3b5b74;font-weight:600;min-height:24px}.model-note p{max-width:1000px;line-height:1.8}.optics .zsa-footer{justify-content:space-between;font-size:10px;margin-top:25px;padding-top:18px;color:#567085}.optics .zsa-th-instructions{font-size:14px}.optics .zsa-th-instructions li{margin:14px 0}.optics .zsa-th-instructions h2{margin:0}.optics .zsa-th-instructions ol{padding-left:22px}
@media(min-width:1600px){.optics{margin-top:20px;border:1px solid #e1e8f0;border-radius:18px}}
@media(max-width:1050px){.workspace{grid-template-columns:220px minmax(0,1fr);gap:15px}.optics{padding:22px}.control-card{padding:15px}.bench-tools{gap:9px;padding:12px}.scene-bottom{font-size:7px;padding:12px}.readings strong{font-size:20px}.readings{padding:16px;gap:9px}.readings>div+div{padding-left:12px}}
@media(max-width:760px){.optics{padding:18px 14px}.intro{padding:20px 0}.intro h2{font-size:24px}.intro a{display:none}.workspace{display:flex;flex-direction:column}.controls{width:100%;grid-template-columns:1fr 1fr}.control-card:last-child{grid-column:1/-1}.bench-card{width:100%}.zsa-th-identity{flex-basis:100%}.zsa-th-header-tools{margin-left:0}.zsa-th-topline{gap:12px}.scene-topline{font-size:7px;padding:10px}.scene-bottom{font-size:7px;letter-spacing:.03em}.bench-heading{padding:15px}.bench-heading h3{font-size:18px}.readings span{font-size:8px;letter-spacing:.03em}.readings strong{font-size:19px}.bench-tools .reset{margin-left:0}.bench-tools{gap:11px}.optics .zsa-footer{gap:6px}.explanation{padding:0 16px 16px}}
@media(max-width:380px){.controls{grid-template-columns:1fr}.control-card:last-child{grid-column:auto}.readings{padding:13px 10px;gap:6px}.readings>div+div{padding-left:6px}.readings strong{font-size:17px}.scene-bottom{align-items:start;flex-direction:column;gap:4px}}