:root{--bg-void:#0d0d0f;--panel:#17171a;--panel-border:#2a2a30;--text:#e8e5db;--text-dim:#9c968a;--brand-orange:#ff8a1f;--brand-orange-deep:#d9650c;}
*{box-sizing:border-box;}
html,body{margin:0;padding:0;}
body{background:radial-gradient(ellipse 800px 500px at 50% -10%,rgba(255,138,31,.07),transparent 60%),var(--bg-void);color:var(--text);font-family:'IBM Plex Mono',monospace;min-height:100vh;padding:32px 14px 70px;display:flex;flex-direction:column;align-items:center;}
.topbar{width:100%;max-width:760px;display:flex;align-items:center;justify-content:space-between;margin-bottom:24px;font-family:'Space Mono',monospace;}
.brand{display:flex;align-items:center;gap:10px;color:var(--text);font-weight:700;letter-spacing:.06em;text-decoration:none;font-size:14px;}
.brand-dot{width:9px;height:9px;border-radius:2px;background:var(--brand-orange);box-shadow:0 0 8px rgba(255,138,31,.7);}
.back{color:var(--text-dim);text-decoration:none;font-size:12px;border:1px solid var(--panel-border);padding:6px 12px;border-radius:20px;}
.back:hover{color:var(--text);border-color:var(--brand-orange);}
.doc{width:100%;max-width:760px;background:var(--panel);border:1px solid var(--panel-border);border-radius:16px;padding:32px 28px;}
h1{font-family:'Space Mono',monospace;font-size:24px;margin:0 0 8px;line-height:1.3;}
h1 span{color:var(--brand-orange);}
.lead{font-size:13.5px;line-height:1.8;color:var(--text-dim);margin:0 0 20px;}
h2{font-family:'Space Mono',monospace;font-size:14px;letter-spacing:.04em;text-transform:uppercase;color:var(--brand-orange);margin:30px 0 12px;}
p,li{font-size:14px;line-height:1.9;margin:0 0 12px;}
ul,ol{padding-left:22px;margin:0 0 14px;}
b{color:#fff;}
a{color:var(--brand-orange);text-decoration:none;}a:hover{text-decoration:underline;}
.tool{background:#101013;border:1px solid var(--panel-border);border-radius:12px;padding:18px;margin:0 0 8px;}
.row{display:flex;flex-wrap:wrap;gap:10px;margin-bottom:12px;align-items:center;}
.row label{font-size:12px;color:var(--text-dim);min-width:60px;}
select{color-scheme:dark;}
option{background:#17171a;color:#e8e5db;}
input,select{background:#0d0d0f;color:var(--text);border:1px solid var(--panel-border);border-radius:8px;padding:9px 10px;font-family:inherit;font-size:14px;min-width:0;}
input:focus,select:focus{outline:none;border-color:var(--brand-orange);}
input[type=number]{width:110px;}
.btn{background:var(--brand-orange);color:#17171a;font-weight:700;border:0;border-radius:10px;padding:10px 16px;font-family:inherit;font-size:13px;cursor:pointer;}
.btn:hover{background:var(--brand-orange-deep);color:#fff;}
.btn.ghost{background:transparent;color:var(--text);border:1px solid var(--panel-border);}
.btn.ghost:hover{border-color:var(--brand-orange);}
.result{margin-top:14px;padding:14px;border-radius:10px;background:#0d0d0f;border:1px solid var(--brand-orange);font-size:14px;line-height:1.9;white-space:pre-wrap;word-break:break-word;min-height:24px;}
.result.empty{border-color:var(--panel-border);color:var(--text-dim);}
.big{font-family:'Space Mono',monospace;font-size:26px;color:var(--brand-orange);}
.subj{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(0,1fr) minmax(0,1fr) minmax(0,1fr) auto;gap:8px;margin-bottom:8px;}
.subj input,.subj select{width:100%;}
table.m{border-collapse:separate;border-spacing:4px;margin:6px 0;}
table.m input{width:58px;text-align:center;padding:7px 4px;}
.matwrap{display:flex;flex-wrap:wrap;gap:22px;}
.cta{display:inline-block;background:var(--brand-orange);color:#17171a;font-weight:700;padding:10px 18px;border-radius:10px;font-size:13px;}
.cta:hover{background:var(--brand-orange-deep);color:#fff;text-decoration:none;}
.related{display:flex;flex-wrap:wrap;gap:8px;margin-top:8px;}
.related a{border:1px solid var(--panel-border);border-radius:20px;padding:6px 12px;font-size:12px;color:var(--text);}
.related a:hover{border-color:var(--brand-orange);text-decoration:none;}
details{border-bottom:1px solid var(--panel-border);padding:10px 0;}
summary{cursor:pointer;font-size:14px;color:#fff;}
details p{margin:8px 0 0;color:var(--text-dim);}
footer{width:100%;max-width:760px;margin-top:28px;text-align:center;font-size:12px;color:var(--text-dim);line-height:2;}
@media(max-width:560px){.doc{padding:22px 16px;}h1{font-size:20px;}.subj{grid-template-columns:minmax(0,1fr) minmax(0,1fr) minmax(0,1fr) auto;}.subj>:first-child{grid-column:1/-1;}}

.gp-overlay{position:fixed;inset:0;background:rgba(0,0,0,.65);z-index:99999;display:flex;align-items:center;justify-content:center;padding:16px;}
.gp-box{background:#1b1b1f;border:1px solid #2a2a30;border-radius:16px;padding:16px;width:100%;max-width:340px;}
.gp-title{color:#9c968a;font-size:12px;letter-spacing:.06em;text-transform:uppercase;margin-bottom:12px;text-align:center;}
.gp-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:8px;}
.gp-btn{background:#0d0d0f;color:#fff;border:1px solid #2a2a30;border-radius:10px;padding:14px 0;font-size:16px;font-weight:700;cursor:pointer;font-family:inherit;}
.gp-btn.active{background:#ff8a1f;color:#17171a;border-color:#ff8a1f;}
.share{display:inline-block;margin-top:8px;border:1px solid var(--panel-border);border-radius:20px;padding:6px 12px;font-size:12px;color:var(--text);}
.share:hover{border-color:var(--brand-orange);text-decoration:none;}
.tool h3{font-family:'Space Mono',monospace;font-size:13px;margin:0 0 10px;color:#fff;}
.tool+.tool{margin-top:14px;}
.row select{max-width:100%;}
.note{font-size:12px;line-height:1.8;color:var(--text-dim);}
table.f{border-collapse:collapse;width:100%;margin:6px 0 14px;font-size:13px;}
table.f th,table.f td{border:1px solid var(--panel-border);padding:8px 10px;text-align:left;}
table.f th{color:var(--brand-orange);font-weight:600;}

.chips{display:flex;flex-wrap:wrap;gap:6px;margin:0 0 12px;align-items:center;}
.chips .lbl{font-size:12px;color:var(--text-dim);margin-right:4px;}
.chips button{background:transparent;color:var(--text);border:1px solid var(--panel-border);border-radius:20px;padding:5px 11px;font-family:inherit;font-size:12px;cursor:pointer;}
.chips button:hover{border-color:var(--brand-orange);}
.tool input.wide{width:100%;font-size:15px;}
.eqout{font-family:'Space Mono',monospace;font-size:19px;line-height:1.8;color:#fff;word-break:break-word;}
.eqout .arrow{color:var(--brand-orange);padding:0 6px;}
.tbl-wrap{overflow-x:auto;margin-top:10px;}
.tbl-wrap table.f{margin:0;}
.okmark{color:#5fd38a;font-weight:700;}
.err{color:#ff9d7a;}
sub{font-size:.7em;}

.fr{display:inline-flex;flex-direction:column;vertical-align:middle;text-align:center;margin:0 3px;}
.fr .nu{border-bottom:1px solid currentColor;padding:0 4px;}
.fr .de{padding:0 4px;}
.steps{margin-top:12px;}
.stp{padding:5px 0 5px 12px;border-left:2px solid var(--panel-border);font-size:13.5px;line-height:1.9;}
.stp.top{border-left-color:var(--brand-orange);margin-top:6px;}
.ans{font-family:'Space Mono',monospace;font-size:18px;color:#fff;line-height:2;word-break:break-word;}
.okbadge{display:inline-block;font-size:11px;border:1px solid #5fd38a;color:#5fd38a;border-radius:20px;padding:1px 8px;margin-left:8px;vertical-align:middle;}
.warnbox{margin-top:8px;color:#ff9d7a;font-size:13px;}
.blk{margin-top:14px;padding-top:10px;border-top:1px dashed var(--panel-border);}
.blk>h4{margin:0 0 6px;font-size:13px;color:var(--brand-orange);font-family:'Space Mono',monospace;}

.tool input[type=date]{background:rgba(255,255,255,.06);color:var(--text);border:1px solid var(--panel-border);border-radius:8px;padding:8px 10px;font-family:inherit;font-size:14px;color-scheme:dark light;}
.tool textarea.wide{width:100%;min-height:180px;resize:vertical;font-family:inherit;font-size:15px;line-height:1.7;padding:12px;background:rgba(255,255,255,.06);color:var(--text);border:1px solid var(--panel-border);border-radius:10px;box-sizing:border-box;}
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(110px,1fr));gap:8px;margin-top:10px;}
.stat{border:1px solid var(--panel-border);border-radius:10px;padding:10px;text-align:center;}
.stat b{display:block;font-family:'Space Mono',monospace;font-size:20px;color:#fff;}
.stat span{font-size:11px;color:var(--text-dim);}
.pt{display:grid;grid-template-columns:repeat(18,minmax(0,1fr));gap:3px;margin:10px 0;overflow-x:auto;min-width:640px;}
.pt-wrap{overflow-x:auto;}
.pt button{aspect-ratio:1/1.05;border:1px solid rgba(255,255,255,.18);border-radius:5px;color:#fff;font-family:inherit;cursor:pointer;padding:0;display:flex;flex-direction:column;align-items:center;justify-content:center;line-height:1.1;}
.pt button i{font-style:normal;font-size:8px;opacity:.75}
.pt button b{font-size:13px}
.pt button.dim{opacity:.18}
.pt button.sel{outline:2px solid #fff}
.c-alkali{background:#b04a3d}.c-alkaline{background:#b0793d}.c-transition{background:#3d6fb0}.c-post{background:#3d8f8f}.c-metalloid{background:#7d9a3d}.c-nonmetal{background:#3d9a5c}.c-halogen{background:#8f3d9a}.c-noble{background:#6d4fb0}.c-lanthanide{background:#a04d7d}.c-actinide{background:#7d4d4d}
.legend{display:flex;flex-wrap:wrap;gap:6px;margin:6px 0}
.legend button{border:1px solid rgba(255,255,255,.25);color:#fff;border-radius:20px;padding:4px 10px;font-size:11px;cursor:pointer;font-family:inherit}
.uc-box{text-align:center}.uc-box svg{max-width:460px;width:100%;height:auto}
.uc text{fill:var(--text);font-family:'IBM Plex Mono',monospace}.uc .ax{stroke:var(--text-dim)}.uc .ring{fill:none;stroke:var(--brand-orange);stroke-width:2}.uc .pt2{fill:var(--brand-orange)}
@media print{
 body{background:#fff!important;color:#000!important}
 .topbar,footer,.related,.cta,.noprint,details,.chips,.legend,script,ins{display:none!important}
 .doc{max-width:100%!important;padding:0!important;margin:0!important}
 h1,h1 span,h2,h3,.lead,p,li,td,th,b{color:#000!important}
 table.f th,table.f td{border-color:#888!important}
 .uc text{fill:#000!important}.uc .ax{stroke:#000!important}.uc .ring{stroke:#000!important}.uc .pt2{fill:#000!important}
 h2{page-break-after:avoid}table.f,.uc-box{page-break-inside:avoid}
}