.guide-content .wrap{width:min(1080px,calc(100% - 40px));margin-inline:auto}
.edition-scope{max-width:900px;font-size:.93rem;color:#425064;margin-top:18px}
.edition-context{display:flex;flex-wrap:wrap;align-items:center;gap:8px 12px;font-size:.9rem;color:#495767;margin:0 0 18px}
.edition-label,.topic-list summary .edition-label{display:inline-block;width:fit-content;max-width:100%;padding:4px 10px;border:1px solid #b9d1bb;border-radius:6px;background:#edf6ee;color:#255a26;font-size:.78rem;font-weight:800;line-height:1.4;letter-spacing:0}
.topic-list summary .edition-label{margin-top:10px}
.edition-label--professional,.topic-list summary .edition-label--professional{background:#f1effa;border-color:#cec8e6;color:#4c427c}




.intro{padding:55px 0 32px;background:linear-gradient(120deg,#edf7f0,#fff 60%,#f1effa)}
.eyebrow{color:var(--aa-verde);text-transform:uppercase;letter-spacing:.13em;font-size:.8rem;font-weight:850;margin:0 0 12px}
h1{font-size:clamp(2.3rem,5.5vw,4.5rem);line-height:1.07;color:var(--blue);margin:0 0 20px;letter-spacing:-.035em}
.lead{max-width:760px;font-size:1.2rem;color:#495767}
.lesson-nav{display:flex;gap:10px;flex-wrap:wrap;margin-top:28px}
.lesson-nav a{border:1px solid #bbcbbc;border-radius:9px;background:#fff;padding:11px 16px;color:var(--blue);font-weight:750}
.lesson{padding-block:42px;scroll-margin-top:130px}
h2{font-size:clamp(1.65rem,3.5vw,2.2rem);color:var(--blue);line-height:1.2;margin:0 0 14px;letter-spacing:-.02em}
h3{color:var(--blue);font-size:1.15rem;margin:0 0 8px}
p{margin:0 0 16px}p:last-child{margin-bottom:0}
.reading-layout{display:grid;grid-template-columns:.85fr 1.4fr;gap:44px;align-items:start;margin-block:28px}
.element-demo{margin:0;padding:26px;background:#dfeef3;border-radius:22px}
/* Colores tomados del arte original de la Escolar: carbono y tipografía. */
.element-card{max-width:260px;margin:auto;background:#f68290;border:4px solid #fff;border-radius:24px 8px 24px 8px;color:#1c161a;padding:18px;display:grid;grid-template-columns:minmax(0,1fr) auto;align-content:start;aspect-ratio: .78;box-shadow:0 8px 20px #283b8610}
.marker{display:inline-flex;flex:none;align-items:center;justify-content:center;width:25px;height:25px;border-radius:50%;font-size:.8rem;line-height:1;color:var(--blue);background:#edf2f8;border:1px solid #c1cadc;font-weight:800;vertical-align:middle}
.atomic-number{grid-column:2;grid-row:1;display:flex;align-items:center;gap:7px;align-self:start;font-size:2.2rem;padding-top:5px}
.symbol{grid-column:1;grid-row:1;display:flex;align-items:center;gap:8px}.symbol strong{font-size:5rem;line-height:1.1}
.element-name{grid-column:1 / -1;font-size:1.25rem;text-transform:uppercase;font-weight:850;display:flex;align-items:center;gap:8px;padding:10px 0 6px}
.atomic-mass{grid-column:1 / -1;display:flex;align-items:center;gap:8px;font-size:1.6rem;font-style:italic}
.element-card .marker{width:21px;height:21px;background:#fff;color:#1c161a;border-color:#fff;font-size:.72rem;font-style:normal}
figcaption{font-size:.85rem;color:#495767;margin-top:20px;line-height:1.5}
.clues{margin:0}.clues>div{padding:0 0 16px;margin-bottom:16px;border-bottom:1px solid var(--line)}
.clues>div:last-child{margin-bottom:0}.clues dt{display:flex;align-items:center;gap:9px;color:var(--blue);font-weight:850;margin-bottom:7px}.clues dd{margin:0;color:#425064}
.key-note{background:#edf6ee;border-left:4px solid var(--aa-verde);border-radius:0 14px 14px 0;padding:24px 28px}
.band{background:#eef4f1;border-block:1px solid var(--line)}
.two-cards{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin:24px 0 18px}
.info-card{padding:25px;border:1px solid var(--line);background:#fff;border-radius:16px}
.direction{display:block;font-size:2.3rem;color:var(--aa-verde);line-height:1;margin-bottom:16px}
.small-note{font-size:.93rem;color:#495767;max-width:860px}
.practice{border:1px solid #c6d2cc;border-radius:14px;overflow:hidden;background:#fff;margin-top:24px}
details+details{border-top:1px solid var(--line)}summary{padding:18px 22px;cursor:pointer;color:var(--blue);font-weight:800;min-height:52px}details[open] summary{background:#f1f6f2}details p{padding:18px 22px;color:#425064}
.back-resources{margin:24px 0}.back-resources>div{display:grid;grid-template-columns:230px 1fr;gap:25px;padding:18px 0;border-top:1px solid #cbd9d0}.back-resources dt{color:var(--aa-verde);font-weight:850}.back-resources dd{margin:0;color:#425064}
.edition-link{display:inline-block;color:var(--blue);font-weight:850;padding:12px 0;text-decoration:underline;text-underline-offset:4px}
.sources{padding-block:35px;font-size:.87rem;color:#495767}.sources h2{font-size:1.1rem}.sources a{color:var(--blue);text-decoration:underline}.sources li{margin-block:7px}.review-note{margin-top:22px}
.scope-note{max-width:900px;font-size:.9rem;color:#495767;margin-top:24px}
.source-line{font-size:.83rem;color:#495767;margin-top:14px;line-height:1.6}
.source-line a,.safety-link a,.resource-links a{color:var(--blue);text-decoration:underline;text-underline-offset:3px;overflow-wrap:anywhere}
.safety-link{border-left:3px solid #769d75;padding:10px 16px;background:#f0f6ef;margin-top:20px;color:#334737;border-radius:0 8px 8px 0}
.electron-expression{font-size:clamp(1.8rem,5vw,2.5rem);font-weight:800;color:var(--blue);margin:22px 0;word-spacing:.1em;line-height:1.4}
.electron-expression sup{font-size:.6em}
.topic-list{margin-block:24px;border:1px solid #bfcec5;border-radius:14px;overflow:hidden;background:#fff}
.topic-list summary span{display:block;color:#526174;font-weight:500;font-size:.9rem;margin-top:4px}
.topic-body{padding:8px 24px 24px;max-width:940px}
.topic-body p{padding:0;margin:14px 0 0;color:inherit}
.topic-body .safety-link{padding:12px 16px}
.topic-body .source-line{color:#495767}
.topic-list details{scroll-margin-top:130px}
.system-list{margin:12px 0}.system-list>div{padding:14px 0;border-bottom:1px solid var(--line)}
.system-list dt{font-weight:850;color:var(--blue);margin-bottom:5px}.system-list dd{margin:0}
.fds-guide{margin-top:24px}.fds-guide dl{display:grid;grid-template-columns:1fr 1fr;gap:8px 24px;margin-block:20px}
.fds-guide dl>div{display:grid;grid-template-columns:58px 1fr;gap:12px;padding-block:8px;border-top:1px solid #c8d9ca}
.fds-guide dt{font-weight:850;color:var(--aa-verde)}.fds-guide dd{margin:0}
.professional-resources{margin-top:24px;padding-top:24px;border-top:1px solid #c8d9ca}
.resource-links{padding-left:20px;margin-bottom:0}.resource-links li{padding-block:5px}
.practice+.practice{margin-top:12px}
@media(max-width:700px){.fds-guide dl{grid-template-columns:1fr}.topic-body{padding:8px 18px 22px}.topic-list summary{padding:16px 18px}.lesson-nav a{flex:1 1 42%}.electron-expression{font-size:1.8rem}}
a:focus-visible,summary:focus-visible{outline:3px solid var(--blue);outline-offset:4px}
@media(max-width:700px){.intro{padding-top:32px}.reading-layout,.two-cards{grid-template-columns:1fr;gap:22px}.element-demo{max-width:390px;width:100%;margin:auto}.lesson{padding-block:30px}.back-resources>div{grid-template-columns:1fr;gap:6px}.key-note{padding:20px}.lesson-nav a{flex:1 1 42%;font-size:.87rem;padding:12px}.clues dt{flex-wrap:wrap}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}

/* Evitar que el encabezado fijo tape los destinos del índice. */
.guide-content [id]{scroll-margin-top:130px}
@media(max-width:760px){.guide-content [id]{scroll-margin-top:var(--aa-mobile-anchor-offset,160px)}}