/* BTH 3.0 — independent Google-inspired interface. No legacy stylesheets. */
body.bth-design{--bth-blue:#2863ce;--bth-ink:#202124;--bth-muted:#6a7078;--bth-line:#e7eaee;--bth-bg:#f7f9fc;--bth-content-width:1440px;--bth-color-primary:#2863ce;--bth-color-text:#202124;--bth-color-muted:#6a7078;--bth-color-border:#e7eaee;margin:0;background:#fff;color:var(--bth-ink);font:15px/1.7 Arial,"Helvetica Neue",sans-serif}
.bth-design *{box-sizing:border-box}.bth-design a{color:var(--bth-blue);text-underline-offset:3px}:where(.bth-design button,.bth-design input,.bth-design select,.bth-design textarea){font:inherit}.bth-design button{cursor:pointer}.bth-design :is(a,button,input,select,textarea,summary,[tabindex]):focus-visible{outline:3px solid #8ab4f8;outline-offset:3px}.bth-design h1,.bth-design h2,.bth-design h3{color:var(--bth-ink);font-weight:500;line-height:1.25;letter-spacing:-.035em;margin:0 0 16px}.bth-design h1{font-size:clamp(30px,3.4vw,46px)}.bth-design h2{font-size:26px}.bth-design h3{font-size:19px}.bth-design p{margin:0 0 18px}.bth-design img{max-width:100%;height:auto}.bth-design [hidden]{display:none!important}.bth-design .screen-reader-text{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap}.bth-design .bth-skip:focus{position:fixed;left:12px;top:12px;width:auto;height:auto;clip:auto;background:#fff;padding:12px;z-index:10000}
.bth-site-header{border-bottom:1px solid var(--bth-line);background:#fff}.bth-header-inner{max-width:1500px;margin:auto;padding:20px 36px;display:flex;align-items:center;justify-content:space-between;gap:24px}.bth-brand{display:flex;align-items:center;gap:12px}.bth-brand a{text-decoration:none}.bth-brand-mark{position:relative;display:grid;place-items:center;width:44px;height:48px;color:#2863ce;background:#e8f0fe;border-radius:8px;font-size:28px}.bth-brand-mark small{position:absolute;top:3px;right:5px;font-size:10px}.bth-brand .custom-logo-link img{width:48px;max-height:52px;object-fit:contain}.bth-brand-name{font-size:12px;font-weight:700;letter-spacing:.9px;color:#20313c!important}.bth-brand-name span{display:block;font-size:10px;font-weight:400;letter-spacing:0;color:#7d858d;margin-top:2px}.bth-primary-menu ul{list-style:none;display:flex;gap:6px;margin:0;padding:0}.bth-primary-menu li{position:relative}.bth-primary-menu a{display:block;padding:8px 14px;text-decoration:none;color:#4c535b;font-size:13px;border-radius:22px}.bth-primary-menu a[aria-current=page],.bth-primary-menu .current-menu-item>a{color:#245fc7;background:#edf3fe}.bth-primary-menu a:hover{background:#f3f6fa}.bth-primary-menu .sub-menu{display:none;position:absolute;top:100%;left:0;background:white;min-width:200px;border:1px solid var(--bth-line);box-shadow:0 10px 24px #20212415;z-index:30;padding:7px;border-radius:10px}.bth-primary-menu li:focus-within>.sub-menu,.bth-primary-menu li:hover>.sub-menu{display:block}.bth-menu-toggle{display:none;background:#f3f6fa;color:#344b67;border:0;border-radius:8px;padding:10px 14px}
.bth-site-content{max-width:1500px;margin:auto;padding:34px 36px 64px}.bth-screen{width:100%;min-width:0}.bth-ui{max-width:1440px;margin:auto}.bth-editorial,.bth-reading-width{max-width:850px;margin:32px auto}.bth-editorial{padding-top:12px}.bth-editorial h2,.bth-reading h2{margin-top:32px}.bth-editorial h3,.bth-reading h3{margin-top:28px}.bth-editorial p,.bth-reading p{line-height:1.85;color:#4a535e}.bth-editorial table,.bth-reading table{display:block;width:100%;overflow-x:auto;border-collapse:collapse}.bth-design :is(td,th){padding:12px;border:1px solid var(--bth-line);text-align:left}.bth-design th{background:#f5f8fc;font-weight:500}.bth-design blockquote{margin:24px 0;background:#f5f8fc;border-left:3px solid #8ab4f8;padding:20px}.bth-design pre{overflow:auto;background:#f5f8fc;padding:18px;border-radius:8px}.bth-ui-badge{display:inline-block;background:#edf3fe;color:#3464ad;padding:5px 11px;border-radius:7px;font-size:11px}.bth-eyebrow,.bth-ed-kicker,.bth-el-eyebrow,.bth-type-kicker,.bth-lr-kicker,.bth-content-kicker{font-size:10px;letter-spacing:1.5px;color:#4777bf;display:block;margin-bottom:13px;text-transform:uppercase}.bth-ui-muted{color:var(--bth-muted)}.bth-ui-button,.bth-detail-link,.bth-lr-button{display:inline-flex;align-items:center;gap:10px;justify-content:center;background:#1a73e8;color:#fff!important;border:0;border-radius:24px;padding:11px 19px;text-decoration:none;font-size:13px;font-weight:500}.bth-ui-button:hover,.bth-detail-link:hover{background:#155fbe}.bth-ui-button--secondary{background:#eef3fb;color:#2863ce!important}.bth-ui-input,.bth-design .bth-site-search input,.bth-design .bth-comments input,.bth-design .bth-comments textarea{border:1px solid #dbe1e9;background:#f8fafd;border-radius:9px;padding:12px 15px;color:#202124;width:100%;min-width:0}.bth-ui-notice,.bth-data-note{background:#f2f6fc;border-radius:10px;padding:16px 20px;color:#63758a;font-size:12px;margin:18px 0}.bth-workbench-heading{display:flex;align-items:end;justify-content:space-between;gap:24px;margin:4px 0 28px}.bth-workbench-heading h1{font-size:30px;margin:0}.bth-workbench-heading .bth-eyebrow{margin-bottom:10px}.bth-workbench-heading .bth-ui-badge{background:transparent;color:#7c8795}
/* Interactive periodic table */
.bth-periodic-wrap{display:grid;grid-template-columns:minmax(0,1fr) 300px;align-items:start;gap:34px;margin:0 0 34px}.bth-table-side{min-width:0}.bth-periodic-head{margin-bottom:10px}.bth-periodic-search{display:flex;gap:12px;align-items:center;border-radius:26px;padding:10px 16px;background:#f5f7fa;border:1px solid transparent}.bth-periodic-search:focus-within{border-color:#a8c7fa;background:#fff}.bth-periodic-search>span{color:#8b9299;font-size:20px}.bth-design .bth-periodic-search input{border:0;box-shadow:none;background:transparent;padding:0;min-width:0;width:100%;color:#30363e;font-size:14px}.bth-periodic-filters{display:flex;gap:5px;flex-wrap:wrap;padding:4px 0 10px}.bth-filter-btn{display:flex;align-items:center;gap:5px;background:transparent;color:#707781;border:0;border-radius:6px;padding:5px 7px;font-size:10px;white-space:nowrap}.bth-filter-btn:hover,.bth-filter-btn.is-active{background:#e8f0fe;color:#174ea6}.bth-filter-color{display:inline-block;width:7px;height:7px;border-radius:50%;flex-shrink:0}.bth-search-status{font-size:11px;color:#8a929b;min-height:18px;margin:0 0 9px!important}.bth-periodic-scroll{overflow-x:auto;padding:3px 3px 8px;max-width:100%;border-radius:3px}.bth-periodic-grid{display:grid;grid-template-columns:repeat(18,minmax(0,1fr));grid-template-rows:repeat(9,66px);gap:3px;min-width:800px}.bth-periodic-wrap a.bth-element{position:relative;display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;padding:8px 2px 4px;border:0;border-radius:5px;text-decoration:none;min-width:0;color:var(--tile-ink);background:var(--tile-bg);transition:opacity .15s,transform .15s}.bth-atomic-number{position:absolute;left:5px;top:3px;font-size:9px;font-weight:600}.bth-symbol{font-size:25px;font-weight:400;line-height:1.3}.bth-name{font-size:9px;font-weight:600;max-width:100%;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.bth-element:hover{transform:translateY(-2px);box-shadow:0 2px 8px #20212420}.bth-element.is-selected{outline:2px solid #4285f4;outline-offset:1px;z-index:1}.bth-element.is-filtered-out{opacity:.18}.bth-periodic-note{color:#8a929b;font-size:10px;margin:12px 0!important}.bth-periodic-note a{margin-left:8px}
:is(.bth-cat-nonmetal,.bth-ed-type-nonmetal,.bth-el-nonmetal,.bth-el-type-nonmetal,.bth-cat-halogen,.bth-ed-type-halogen,.bth-el-halogen,.bth-el-type-halogen){--tile-bg:#e5eeff;--tile-ink:#2961d3}:is(.bth-cat-alkali,.bth-ed-type-alkali,.bth-el-alkali,.bth-el-type-alkali){--tile-bg:#e0f5fa;--tile-ink:#32778b}:is(.bth-cat-alkaline,.bth-ed-type-alkaline,.bth-el-alkaline,.bth-el-type-alkaline){--tile-bg:#fdebec;--tile-ink:#c62f3a}:is(.bth-cat-transition,.bth-ed-type-transition,.bth-el-transition,.bth-el-type-transition){--tile-bg:#f0eafd;--tile-ink:#663bd9}:is(.bth-cat-post-transition,.bth-ed-type-post-transition,.bth-el-post,.bth-el-type-post-transition){--tile-bg:#e2f6e9;--tile-ink:#245a2a}:is(.bth-cat-metalloid,.bth-ed-type-metalloid,.bth-el-metalloid,.bth-el-type-metalloid){--tile-bg:#fdf7e6;--tile-ink:#956222}:is(.bth-cat-noble,.bth-ed-type-noble,.bth-el-noble,.bth-el-type-noble){--tile-bg:#fcebf1;--tile-ink:#be315e}:is(.bth-cat-lanthanide,.bth-ed-type-lanthanide,.bth-el-lanthanide,.bth-el-type-lanthanide){--tile-bg:#e6f3fe;--tile-ink:#315e83}:is(.bth-cat-actinide,.bth-ed-type-actinide,.bth-el-actinide,.bth-el-type-actinide){--tile-bg:#fcecdf;--tile-ink:#b94828}.bth-filter-color{background:var(--tile-ink,#adb8c7)}
.bth-element-detail{position:sticky;top:24px;padding:22px 8px 20px 20px;min-width:0}.bth-detail-top{display:flex;gap:18px;align-items:center}.bth-detail-tile{display:none}.bth-detail-top h2{font-size:36px;font-weight:400;letter-spacing:-1.2px;margin-bottom:10px}.bth-detail-top p{font-size:12px;color:#7b8189;margin:0}.bth-detail-top .bth-detail-kicker{color:#3a73c9;margin-bottom:8px;font-size:14px}.bth-atom{width:100%;max-width:280px;display:block;margin:20px auto 4px;aspect-ratio:1}.bth-atom-label{text-align:center;font-size:10px;color:#8a919a;margin-bottom:20px}.bth-detail-facts{display:grid;gap:15px;margin:22px 0}.bth-detail-facts small{font-size:11px;color:#8a929b;display:block}.bth-detail-facts b{font-size:14px;color:#47515d;font-weight:400}.bth-detail-link{font-size:12px;padding:10px 17px}.bth-learning-section{border-top:1px solid var(--bth-line);padding-top:34px;margin-top:30px}.bth-learning-section>h2{font-size:24px}.bth-learn-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.bth-learn-grid>a{padding:25px;background:#eff5fc;border-radius:14px;text-decoration:none;color:#344b67;display:flex;flex-direction:column}.bth-learn-grid>a:nth-child(2){background:#f3effa}.bth-learn-grid>a:nth-child(3){background:#fcf5e9}.bth-learn-grid span{font-size:9px;letter-spacing:1px;margin-bottom:24px}.bth-learn-grid h3{font-size:18px}.bth-learn-grid p{font-size:12px;color:#74808f}.bth-learn-grid b{margin-top:auto;font-size:12px;font-weight:500}
/* Directory, classification and element detail */
.bth-ed-wrap,.bth-type-wrap,.bth-lr-wrap,.bth-content-wrap{max-width:1200px;margin:auto}.bth-ed-breadcrumb-inner,.bth-type-breadcrumb ol,.bth-ui-breadcrumb{display:flex;flex-wrap:wrap;gap:9px;align-items:center;list-style:none;margin:0 0 24px;padding:0;font-size:11px;color:#8691a1}.bth-type-breadcrumb li+li:before{content:'/';padding-right:9px}.bth-ed-hero,.bth-type-hero,.bth-lr-hero{padding:18px 0 30px;border-bottom:1px solid var(--bth-line);margin-bottom:25px}.bth-ed-hero-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:40px;align-items:center}.bth-ed-hero p,.bth-type-hero p,.bth-lr-hero p{max-width:720px;color:#78818e;font-size:14px}.bth-ed-stats,.bth-type-hero-stats,.bth-lr-hero-meta{display:flex;gap:28px;margin:22px 0}.bth-ed-stats>div,.bth-type-hero-stats>div,.bth-lr-hero-meta>div{display:flex;flex-direction:column}.bth-ed-stats strong,.bth-type-hero-stats strong,.bth-lr-hero-meta strong{font-size:24px;font-weight:400}.bth-ed-stats span,.bth-type-hero-stats span,.bth-lr-hero-meta span{font-size:10px;color:#8b929a}.bth-ed-search-card{background:#f7f9fc;padding:24px;border-radius:15px}.bth-ed-search-card h2{font-size:20px}.bth-ed-search-box,.bth-lr-search-box{display:flex;gap:8px;align-items:center}.bth-ed-search-box input,.bth-lr-search-input{flex:1;min-width:0;background:white;border:1px solid #dce3ec;border-radius:9px;padding:12px;font-size:14px;color:#202124}.bth-ed-search-box button,.bth-lr-clear-search{background:transparent;color:#5c7aa2;border:0;padding:10px}.bth-ed-quick{display:flex;gap:6px;flex-wrap:wrap;margin-top:14px;font-size:11px}.bth-ed-quick button,.bth-ed-filters button,.bth-lr-filter-btn{border:1px solid #e4e9f0;border-radius:6px;background:white;color:#6f7b8c;padding:7px 10px;font-size:11px}.bth-ed-filters{display:flex;gap:7px;flex-wrap:wrap;margin:15px 0 26px}.bth-ed-filters .is-active,.bth-lr-filter-btn.is-active{background:#e8f0fe;color:#245fb9;border-color:#cbdcfa}.bth-ed-filter-head{display:none}.bth-ed-grid-head,.bth-type-grid-head{display:flex;align-items:center;justify-content:space-between;gap:20px;margin:25px 0 20px}.bth-ed-grid-head h2,.bth-type-grid-head h2{font-size:22px;margin:0}.bth-ed-grid-head p,.bth-type-grid-head p{font-size:12px;color:#8793a3;margin:8px 0}.bth-ed-count{font-size:12px;color:#8793a3;white-space:nowrap}.bth-ed-grid,.bth-type-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}.bth-ed-card,.bth-type-card{position:relative;background:#fff;border:1px solid var(--bth-line);border-radius:12px;padding:18px;display:grid;grid-template-columns:64px 1fr;column-gap:14px;text-decoration:none;align-items:center}.bth-ed-z,.bth-type-z{position:absolute;top:22px;left:24px;font-size:9px;color:var(--tile-ink)}.bth-ed-symbol,.bth-type-card>a,.bth-type-card .bth-type-symbol{grid-column:1;grid-row:1/5;display:grid;place-items:center;min-height:78px;border-radius:8px;background:var(--tile-bg,#e8f0fe);color:var(--tile-ink,#2863ce);font-size:31px;font-weight:400;text-decoration:none}.bth-ed-name,.bth-type-card h3{font-size:14px;font-weight:500;color:#424c59}.bth-ed-meta,.bth-type-meta{font-size:10px;color:#939aa5}.bth-ed-mass,.bth-type-mass{font-size:12px;color:#77818e}.bth-ed-type-label{font-size:10px;text-decoration:none}.bth-mass-pair{display:inline-flex;gap:5px;flex-wrap:wrap}.bth-mass-round{font-size:.8em;color:#9199a5}.bth-type-actions a{font-size:12px}.bth-type-related{margin:30px 0}.bth-type-related>h2{font-size:20px}.bth-type-related>p{font-size:13px;color:#77818e}.bth-type-related-grid,.bth-content-related-links{display:flex;gap:8px;flex-wrap:wrap}.bth-type-related-card{padding:8px 12px;background:#f5f8fc;border-radius:8px;font-size:12px}.bth-type-intro-card{margin:28px 0}.bth-type-intro-card h2{font-size:22px}.bth-type-intro-card p{color:#77818e}.bth-el-hero{display:grid;grid-template-columns:210px 1fr;gap:40px;padding:24px 0 32px;border-bottom:1px solid var(--bth-line);align-items:start}.bth-el-card{background:var(--tile-bg,#e5eeff);color:var(--tile-ink,#2863ce);padding:20px;border-radius:13px}.bth-el-top{display:flex;align-items:center;justify-content:space-between;font-size:11px;gap:8px}.bth-el-category-pill{font-size:9px}.bth-el-main-face{display:flex;align-items:center;flex-direction:column;padding:18px 0}.bth-el-symbol{font-size:80px;line-height:1.2;font-weight:400}.bth-el-name{font-size:16px}.bth-el-mass{font-size:13px;margin-top:8px}.bth-el-config-card{font-size:10px;margin-top:8px}.bth-el-actions{display:flex;gap:8px;flex-direction:column;margin-top:16px}.bth-el-actions .bth-ui-button{font-size:11px;padding:9px 12px}.bth-el-btn-light{color:#2863ce!important;background:#eef3fb}.bth-el-desc{color:#77818e;font-size:14px;max-width:800px}.bth-el-facts{display:grid;grid-template-columns:repeat(3,1fr);margin-top:28px;border-top:1px solid var(--bth-line)}.bth-el-fact{padding:14px 12px 14px 0;border-bottom:1px solid var(--bth-line)}.bth-el-fact>span{display:block;font-size:10px;color:#8d96a3}.bth-el-fact>strong{font-size:17px;font-weight:400;color:#526174}.bth-el-fact .bth-el-meta-text{font-size:13px}.bth-content-wrap{max-width:950px}.bth-content-intro,.bth-content-card{padding:18px 0;border-bottom:1px solid var(--bth-line)}.bth-content-wrap h2{font-size:24px;margin:20px 0 15px}.bth-content-wrap p,.bth-content-wrap li{color:#6a7686;line-height:1.85;font-size:14px}.bth-content-grid{display:grid;grid-template-columns:1fr 1fr;gap:24px}.bth-content-wide{grid-column:1/-1}.bth-content-table-wrap{overflow-x:auto}.bth-content-table{width:100%;border-collapse:collapse}.bth-electron-pill{background:#f2f6fd;border-radius:10px;padding:15px;display:flex;gap:18px;font-size:13px}.bth-content-related-links a{font-size:12px;padding:5px 10px;background:#f2f6fd;border-radius:7px}.bth-content-internal-link{font-size:13px}
/* Learning resources: real covers and a neutral shelf. */
.bth-lr-layout{display:grid;grid-template-columns:210px 1fr;gap:30px;align-items:start}.bth-lr-filters{background:#f7f9fc;padding:22px;border-radius:12px}.bth-lr-filter-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:18px}.bth-lr-filter-head h2{font-size:16px;margin:0}.bth-lr-filter-head button{border:0;background:transparent;color:#5d7ca5;font-size:11px}.bth-lr-filter-group{margin-bottom:20px}.bth-lr-filter-group h3{font-size:12px;letter-spacing:0;color:#74849a}.bth-lr-filter-options{display:flex;gap:6px;flex-wrap:wrap}.bth-lr-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.bth-lr-card{border:1px solid var(--bth-line);border-radius:13px;overflow:hidden;display:flex;flex-direction:column;background:#fff}.bth-lr-card-image{display:grid;place-items:center;position:relative;aspect-ratio:4/3;background:#f2f5fa;overflow:hidden}.bth-lr-card-image img{width:100%;height:100%;object-fit:contain;padding:18px;transition:transform .18s}.bth-lr-card-image:hover img{transform:scale(1.04)}.bth-lr-card-placeholder{display:grid;place-items:center;min-height:175px;width:100%;font-size:22px;color:#a0aec2;background:#f1f5fb}.bth-lr-card-body{padding:20px;display:flex;flex-direction:column;gap:10px;flex:1}.bth-lr-card h2,.bth-lr-card h3{font-size:17px;line-height:1.5;margin:0}.bth-lr-card h2 a,.bth-lr-card h3 a{text-decoration:none;color:#344b65}.bth-lr-card p{font-size:12px;color:#8a95a5;margin:0}.bth-lr-badge{position:absolute;top:10px;left:12px;border-radius:5px;background:white;color:#5879a7;padding:4px 9px;font-size:10px}.bth-lr-tags{display:flex;gap:5px;flex-wrap:wrap}.bth-lr-tags span{padding:3px 6px;background:#f2f6fc;border-radius:4px;font-size:9px;color:#8091a9}.bth-lr-button{margin-top:auto;font-size:12px;padding:9px 14px}.bth-lr-hero-bottom{display:flex;align-items:center;gap:40px;margin-top:22px}.bth-lr-hero-search{flex:1;max-width:650px}.bth-lr-mobile-search,.bth-lr-mobile-filter-toggle{display:none}.bth-ui-pagination{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin:28px 0}.bth-ui-pagination :is(button,a,span.page-numbers){border:0;background:#f3f6fb;padding:8px 13px;border-radius:7px;color:#5c7191;text-decoration:none;font-size:12px}.bth-ui-pagination .current,.bth-ui-pagination .is-active{background:#e1edff;color:#2863ce}.bth-ui-empty{text-align:center;padding:40px 20px;background:#f7f9fc;border-radius:14px}.bth-ui-empty h2{font-size:23px}.bth-ui-empty p{color:#8b95a2}.bth-lr-empty{margin:20px 0}
/* Reading, archives, search and system screens. */
.bth-post-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px;margin-top:30px}.bth-post-card{border:1px solid var(--bth-line);border-radius:14px;overflow:hidden;display:flex;flex-direction:column}.bth-post-card__image{aspect-ratio:16/9;display:block;overflow:hidden;background:#f3f6fb}.bth-post-card__image img{width:100%;height:100%;object-fit:cover}.bth-post-card__body{padding:24px;display:flex;flex-direction:column;gap:14px;flex:1}.bth-post-card__body h2{font-size:20px;margin:0}.bth-post-card__body h2 a{color:#354b65;text-decoration:none}.bth-post-card__body p{font-size:13px;margin:0}.bth-post-card__body .bth-ui-badge{align-self:start}.bth-post-card__more{font-size:12px;margin-top:auto;text-decoration:none}.bth-archive-description{color:#8290a2;max-width:800px}.bth-single__header{margin-bottom:25px}.bth-single__meta{font-size:12px;color:#8a929e}.bth-single__image{margin:24px 0}.bth-single__image img{border-radius:12px;width:100%}.bth-ui-breadcrumb{color:#8a95a6}.bth-ui-breadcrumb a{text-decoration:none}.bth-site-search{max-width:720px;margin:24px 0}.bth-site-search>label{display:block;font-size:12px;color:#8290a2;margin-bottom:7px}.bth-site-search__row{display:flex;gap:10px}.bth-site-search__row button{flex-shrink:0}.bth-ui-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:24px}.bth-screen--404{text-align:center;padding:50px 0}.bth-screen--404 .bth-ui-badge{font-size:70px;line-height:1.2;background:transparent;color:#8ab4f8;margin-bottom:25px}.bth-screen--404 .bth-site-search{margin:28px auto}.bth-screen--404 .bth-ui-actions{justify-content:center}.bth-author-intro{display:flex;align-items:center;gap:20px;max-width:750px;color:#8593a6}.bth-author-intro img{border-radius:50%}.bth-author-box-card,.bth-public-author{border-top:1px solid var(--bth-line);margin-top:32px;padding-top:25px}.bth-author-box-inner{display:flex;gap:22px}.bth-author-box-avatar{flex:0 0 70px}.bth-author-box-avatar img,.bth-author-box-initial{border-radius:50%;width:70px;height:70px;object-fit:cover}.bth-author-box-initial{display:grid;place-items:center;background:#e8f0fe;color:#2863ce;font-size:30px}.bth-author-box-label,.bth-author-box-count{font-size:10px;color:#929ba8}.bth-author-box-top{display:flex;gap:15px}.bth-author-box-name{font-size:20px;margin:8px 0}.bth-author-box-name a{text-decoration:none}.bth-author-box-desc,.bth-author-box-bio,.bth-author-box-role{font-size:12px;color:#8390a2}.bth-author-box-tags{display:flex;gap:6px;flex-wrap:wrap;font-size:10px}.bth-author-box-actions{font-size:12px;margin-top:10px}.bth-comments{margin-top:40px}.bth-comment-list{list-style:none;margin:0;padding:0}.bth-comment-list .children{list-style:none;padding-left:22px}.bth-comment{padding:20px 0;border-bottom:1px solid var(--bth-line)}.bth-comment header{display:flex;justify-content:space-between;gap:15px;font-size:13px}.bth-comment time{font-size:11px;color:#96a0ae}.bth-comments .bth-ui-label{font-size:12px;color:#7a879b;display:block;margin-bottom:8px}.bth-screen .post-navigation .nav-links{display:grid;grid-template-columns:1fr 1fr;gap:22px;margin:35px 0}.bth-screen .post-navigation a{display:block;background:#f5f8fc;padding:20px;border-radius:10px;text-decoration:none;font-size:13px}.bth-screen .post-navigation span{display:block;color:#96a1b1;font-size:10px;margin-bottom:7px}.bth-password-form{background:#f7f9fc;padding:25px;border-radius:12px}.bth-html-sitemap :is(ul,ol){line-height:2}.bth-html-sitemap h2{margin-top:30px}
/* Footer is a theme component, independent of old widgets and UX Blocks. */
.bth-site-footer{background:#f8f9fb;border-top:1px solid var(--bth-line)}.bth-footer-inner{max-width:1500px;margin:auto;padding:40px 36px 20px;display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;gap:30px}.bth-footer-inner h2,.bth-footer-inner b{font-size:12px;font-weight:600;letter-spacing:.2px;margin-bottom:13px}.bth-footer-brand p{font-size:14px;color:#758296;margin:13px 0}.bth-footer-brand span{font-size:10px;color:#9ba4b1}.bth-footer-inner>div>a{display:block;color:#8490a2;font-size:12px;text-decoration:none;padding:5px 0}.bth-footer-inner>div>a:hover{color:#2863ce}.bth-copyright{grid-column:1/-1;display:flex;justify-content:space-between;gap:15px;border-top:1px solid var(--bth-line);padding-top:20px;font-size:10px;color:#a1aab6}.bth-footer-extra{grid-column:1/-1}.bth-footer-extra ul{display:flex;gap:20px;flex-wrap:wrap;list-style:none;padding:0;margin:0}.bth-footer-extra a{font-size:12px;text-decoration:none}
@media(min-width:1500px){.bth-periodic-grid{grid-template-rows:repeat(9,76px)}.bth-symbol{font-size:30px}.bth-name{font-size:10px}.bth-element-detail{padding-top:28px}}
@media(max-width:1100px){.bth-periodic-wrap{grid-template-columns:minmax(0,1fr) 250px;gap:24px}.bth-element-detail{padding-left:8px}.bth-detail-top h2{font-size:30px}.bth-lr-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.bth-ed-grid,.bth-type-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.bth-ed-hero-grid{gap:25px}}
@media(max-width:760px){.bth-header-inner{padding:16px 18px;flex-wrap:wrap;gap:14px}.bth-menu-toggle{display:block;font-size:12px}.bth-primary-menu{display:none;width:100%}.bth-primary-menu.is-open{display:block}.bth-primary-menu>ul{flex-direction:column}.bth-primary-menu .sub-menu{position:static;box-shadow:none;border:0;display:block;margin-left:14px}.bth-site-content{padding:24px 18px 40px}.bth-workbench-heading{align-items:start;flex-direction:column;gap:10px}.bth-workbench-heading h1{font-size:27px}.bth-workbench-heading .bth-ui-badge{padding:0}.bth-periodic-wrap{grid-template-columns:1fr;gap:12px}.bth-periodic-grid{min-width:820px;grid-template-rows:repeat(9,61px)}.bth-periodic-filters{flex-wrap:nowrap;overflow-x:auto}.bth-element-detail{position:static;border-top:1px solid var(--bth-line);padding:22px 8px}.bth-detail-top{justify-content:center}.bth-atom{max-width:220px;margin-top:10px}.bth-detail-facts{grid-template-columns:repeat(3,1fr);gap:10px}.bth-detail-facts b{font-size:12px;overflow-wrap:anywhere}.bth-detail-top h2{font-size:32px}.bth-learn-grid{grid-template-columns:1fr}.bth-learn-grid>a{padding:22px}.bth-learn-grid span{margin-bottom:14px}.bth-ed-hero-grid{grid-template-columns:1fr;gap:12px}.bth-ed-hero h1,.bth-type-hero h1,.bth-lr-hero h1{font-size:30px}.bth-ed-search-card{padding:18px}.bth-ed-grid,.bth-type-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.bth-ed-card,.bth-type-card{padding:12px;grid-template-columns:44px 1fr;gap:9px}.bth-ed-z,.bth-type-z{top:17px;left:16px;font-size:8px}.bth-ed-symbol{min-height:66px;font-size:25px}.bth-ed-name{font-size:12px}.bth-ed-type-label{font-size:9px}.bth-ed-meta{font-size:9px}.bth-el-hero{grid-template-columns:130px 1fr;gap:20px}.bth-el-card{padding:12px}.bth-el-symbol{font-size:56px}.bth-el-config-card{display:none}.bth-el-top{font-size:9px}.bth-el-category-pill{display:none}.bth-el-title{font-size:30px!important}.bth-el-desc{font-size:12px}.bth-el-facts{grid-template-columns:repeat(2,1fr);margin-top:16px}.bth-el-fact{padding:10px 4px}.bth-el-fact>strong{font-size:14px}.bth-el-actions .bth-ui-button{font-size:10px;padding:8px 10px}.bth-content-grid{grid-template-columns:1fr;gap:0}.bth-content-wrap h2{font-size:22px}.bth-lr-layout{grid-template-columns:1fr}.bth-lr-filters{display:none}.bth-lr-filters.is-open{display:block}.bth-lr-mobile-filter-toggle{display:flex;gap:10px;align-items:center;margin:15px 0;background:#eef3fb;color:#4774b2;border:0;padding:10px 15px;border-radius:8px;font-size:12px}.bth-lr-mobile-search{display:block;margin:15px 0}.bth-lr-desktop-search{display:none}.bth-lr-hero-meta{margin:0}.bth-lr-grid{gap:12px}.bth-lr-card-body{padding:14px}.bth-lr-card h3{font-size:15px}.bth-lr-card p{font-size:11px}.bth-post-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.bth-post-card__body{padding:18px}.bth-footer-inner{padding:30px 20px 20px;grid-template-columns:1fr 1fr;gap:25px}.bth-footer-brand{grid-column:1/-1}.bth-copyright{display:block}.bth-copyright span{display:block;margin-top:8px}.bth-author-box-inner{gap:15px}.bth-author-box-avatar{flex-basis:50px}.bth-author-box-avatar img,.bth-author-box-initial{width:50px;height:50px}.bth-editorial,.bth-reading-width{margin:20px auto}.bth-site-search__row{flex-direction:column}}
@media(max-width:440px){.bth-brand-name{font-size:10px}.bth-brand-name span{font-size:9px}.bth-brand-mark{width:34px;height:39px;font-size:24px}.bth-lr-grid,.bth-post-grid{grid-template-columns:1fr}.bth-detail-facts{grid-template-columns:1fr 1fr}.bth-el-hero{grid-template-columns:1fr}.bth-el-left{max-width:180px;margin:auto}.bth-el-actions{display:none}.bth-screen .post-navigation .nav-links{grid-template-columns:1fr}.bth-ed-card,.bth-type-card{grid-template-columns:37px 1fr;padding:10px;gap:7px}.bth-ed-symbol{font-size:22px}.bth-ed-z{top:14px;left:13px}.bth-ed-type-label{font-size:8px}.bth-ed-meta{font-size:8px}.bth-workbench-heading h1{font-size:25px}}
@media(prefers-reduced-motion:reduce){.bth-design *{transition:none!important;scroll-behavior:auto!important}}
.bth-type-card>strong{grid-column:1;grid-row:1/5;background:var(--tile-bg,#e8f0fe);color:var(--tile-ink,#2863ce);font-size:31px;font-weight:400;min-height:78px;display:grid;place-items:center;border-radius:8px}.bth-type-card>em{font-size:14px;font-style:normal}.bth-type-card>em a{text-decoration:none;color:#44546a}.bth-type-card>small{font-size:12px;color:#8b96a6}.bth-type-related-card a{display:block;text-decoration:none}.bth-type-related-card strong,.bth-type-related-card span{display:block}.bth-type-related-card span{font-size:10px;color:#929eaf}

.bth-design .bth-menu-toggle:is(:hover,:focus){background:#e8f0fe;color:#2863ce}.bth-learn-grid>div{padding:24px;background:#f5f8fc;border-radius:12px}.bth-common-card{display:flex;gap:16px;align-items:center;border:1px solid #e7eaee;padding:18px;border-radius:12px;text-decoration:none}.bth-common-card strong{display:grid;place-items:center;width:50px;height:56px;background:var(--tile-bg);color:var(--tile-ink);border-radius:7px;font-size:25px;font-weight:400}.bth-common-card span{font-size:14px;color:#637389}@media(max-width:760px){.bth-design input[type=search],.bth-design input[type=text],.bth-design textarea{font-size:16px}}
.bth-design .bth-lr-mobile-filter-toggle:is(:hover,:focus){background:#e8f0fe;color:#2863ce}.bth-design .bth-lr-search-input{background:#fff;border:1px solid #dce3ec;border-radius:9px;padding:12px;color:#202124}