@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500;600;700&family=Manrope:wght@400;500;600;700;800&display=swap');
:root{--bg:#f7f6f2;--paper:#fff;--ink:#152c36;--muted:#617077;--line:#dfe3df;--green:#d5f175;--soft:#edf1ea;--radius:18px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:30px}body{margin:0;background:var(--bg);color:var(--ink);font-family:'DM Sans',Arial,sans-serif;line-height:1.6}a{color:inherit}button,input,select{font:inherit}button,a,input,select{touch-action:manipulation}button,a{ -webkit-tap-highlight-color:transparent}button{cursor:pointer}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #477f8b;outline-offset:4px}button:disabled{cursor:default}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.skip{position:absolute;left:20px;top:-100px;z-index:20;background:var(--green);padding:12px}.skip:focus{top:12px}.topbar,main,footer{max-width:1240px;margin:auto;padding-left:48px;padding-right:48px}.topbar{height:108px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line)}.brand{display:flex;gap:13px;align-items:center;text-decoration:none;font-family:Manrope,Arial,sans-serif;font-size:20px;font-weight:800;line-height:1.4;letter-spacing:-.5px}.brand small{display:block;font-family:'DM Sans',Arial,sans-serif;font-size:9px;letter-spacing:2px;font-weight:500;margin-top:3px;color:var(--muted)}.brand i{font-style:normal;color:#8da55a}.brand-icon{display:flex;align-items:center;justify-content:center;gap:1px;width:44px;height:44px;border:1px solid var(--ink);border-radius:12px;font-size:18px;letter-spacing:-1px}.brand-icon span{color:#6f8c3d;transform:translateY(4px)}.nav-link{text-decoration:none;font-size:13px;font-weight:600;display:flex;gap:22px}.hero{display:grid;grid-template-columns:1.2fr 1fr;gap:65px;padding:70px 0 58px;align-items:center}.eyebrow{font-size:10px;letter-spacing:2px;font-weight:700;display:inline-flex;align-items:center;gap:9px}.dot{background:#86a24a;border-radius:50%;width:6px;height:6px}.muted{color:var(--muted)}h1,h2,h3,p{margin:0}h1,h2,h3{font-family:Manrope,Arial,sans-serif}h1{font-size:clamp(42px,5vw,64px);line-height:1.11;letter-spacing:-3px;font-weight:800;margin:22px 0}h1 em{font-style:normal;position:relative;z-index:0}h1 em:after{content:'';position:absolute;left:0;bottom:4px;width:100%;height:17px;background:var(--green);z-index:-1}.hero-text>p{font-size:15px;color:var(--muted);max-width:400px;line-height:1.8;margin-bottom:28px}.button{display:inline-flex;align-items:center;justify-content:center;gap:22px;padding:13px 20px;border-radius:8px;border:1px solid transparent;text-decoration:none;font-size:13px;font-weight:600;line-height:1.4}.primary{background:var(--ink);color:white}.primary:hover{background:#284551}.secondary{background:white;border-color:var(--line);color:var(--ink)}.secondary:hover{background:var(--soft)}.hero-art{min-height:388px;position:relative;background:var(--ink);border-radius:24px;overflow:hidden;color:#dce8e5}.grid-paper{position:absolute;inset:0;opacity:.08;background-image:linear-gradient(#bdcfcc 1px,transparent 1px),linear-gradient(90deg,#bdcfcc 1px,transparent 1px);background-size:28px 28px}.art-label{position:absolute;left:26px;top:24px;font-size:8px;letter-spacing:2px;color:#a6bbb9}.atom{position:absolute;width:94%;height:90%;top:5%;left:3%}.formula{position:absolute;font:italic 17px Georgia,serif;color:#a6bbb9}.formula-one{left:24px;top:70px}.formula-two{right:24px;bottom:80px}.art-bottom{position:absolute;bottom:23px;left:26px;right:26px;display:flex;justify-content:space-between;font-size:9px;color:#a6bbb9}.overview{display:flex;align-items:center;gap:32px;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:20px 0;font-size:12px;color:var(--muted)}.overview strong{font-size:17px;font-family:Manrope,Arial,sans-serif;margin-right:6px;color:var(--ink)}.overview-note{margin-left:auto}.overview-note span{margin-left:10px}.library{padding-top:52px}.section-heading{display:flex;justify-content:space-between;align-items:flex-end;margin-bottom:25px}.section-heading h2{font-size:29px;letter-spacing:-1px;margin-top:6px}.section-heading p{font-size:12px;color:var(--muted);padding-bottom:3px}.toolbar{display:flex;gap:15px;margin-bottom:28px}.search-wrap{display:flex;align-items:center;flex:1;background:#fff;border:1px solid var(--line);border-radius:10px;padding:0 17px;gap:12px;min-width:0}.search-wrap>span{font-size:25px;line-height:1;color:var(--muted)}input{border:0;background:transparent;padding:14px 0;min-width:0;flex:1;font-size:13px;color:var(--ink)}input:focus{outline:none}input::placeholder{color:#7b8589}.search-wrap:focus-within{outline:2px solid #477f8b}kbd{font-size:11px;border:1px solid var(--line);border-radius:4px;padding:0 6px;color:#87918f}select{border:1px solid var(--line);border-radius:10px;background:#fff;color:var(--ink);font-size:12px;padding:12px 34px 12px 14px;max-width:100%}.chapter{border:1px solid var(--line);border-radius:var(--radius);background:#fff;overflow:hidden;margin-bottom:20px}.chapter>summary{list-style:none;cursor:pointer;display:flex;align-items:center;gap:20px;padding:25px 28px}.chapter>summary::-webkit-details-marker{display:none}.chapter-code{display:flex;align-items:center;justify-content:center;width:54px;height:54px;flex-shrink:0;background:#edf2e5;border:1px solid #dce5cb;border-radius:12px;font-family:Manrope,Arial,sans-serif;font-size:20px;font-weight:800}.chapter-info{flex:1;min-width:0}.chapter-info .subject{font-size:9px;color:#65813b;letter-spacing:1.5px;font-weight:700;text-transform:uppercase}.chapter-info h3{font-size:20px;letter-spacing:-.5px;margin:2px 0 3px}.chapter-info p{font-size:11px;color:var(--muted)}.chapter-arrow{font-size:20px;transition:transform .2s}.chapter[open] .chapter-arrow{transform:rotate(180deg)}.chapter-body{padding:0 28px 10px}.resource-group{border-top:1px solid var(--line);padding:22px 0 8px}.group-title{font-size:10px;text-transform:uppercase;letter-spacing:1.4px;color:var(--muted);font-weight:700;margin-bottom:8px}.resource{display:flex;align-items:center;gap:14px;padding:14px 0}.pdf-icon{background:#f3f1ed;border-radius:8px;min-width:36px;height:43px;display:flex;align-items:center;justify-content:center;font-size:9px;color:#7c7e72;letter-spacing:.5px;font-weight:700}.resource-info{flex:1;min-width:0}.resource-title{font-size:13px;font-weight:600}.resource-meta{font-size:10px;color:var(--muted);display:flex;align-items:center;gap:8px;margin-top:3px}.tag{background:var(--soft);padding:1px 7px;border-radius:4px;font-size:9px;color:#566947}.tag.correction{background:#f7eee4;color:#92663b}.resource-actions{display:flex;gap:8px;align-items:center}.read-button{background:var(--ink);color:white;border:0;border-radius:7px;padding:9px 14px;font-size:11px;font-weight:600;white-space:nowrap}.read-button:hover{background:#284551}.download{border:1px solid var(--line);border-radius:7px;padding:8px 12px;text-decoration:none;font-size:11px;white-space:nowrap}.download:hover{background:var(--bg)}.empty{border:1px dashed #b4bcb4;padding:44px 20px;text-align:center;border-radius:16px}.empty h3{font-size:20px}.empty p{font-size:13px;color:var(--muted);margin:10px 0 20px}.help{background:#ecefe7;border-radius:14px;margin:35px 0 52px;padding:22px 26px;display:flex;gap:18px;align-items:center}.help-icon{font-size:25px}.help h2{font-size:13px;margin-bottom:3px}.help p{font-size:12px;color:var(--muted)}footer{border-top:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:16px;padding-top:24px;padding-bottom:26px;font-size:10px;color:var(--muted)}.footer-brand{font-family:Manrope,Arial,sans-serif;font-size:14px;font-weight:800;color:var(--ink);text-decoration:none}.footer-brand span{color:#86a24a}footer>a:last-child{text-decoration:none}dialog{padding:0;border:1px solid var(--line);border-radius:16px;width:min(1120px,96vw);height:92vh;max-height:92dvh;color:var(--ink);background:var(--bg)}dialog::backdrop{background:#122a36b3;backdrop-filter:blur(3px)}dialog[open]{display:flex;flex-direction:column}.reader-bar{display:flex;justify-content:space-between;gap:12px;align-items:center;padding:16px 20px;background:#fff}.reader-bar h2{font-size:15px;margin-top:4px}.reader-bar .eyebrow{font-size:8px}.reader-actions{display:flex;gap:10px;align-items:center;flex-shrink:0}.reader-actions .button{font-size:11px;padding:9px 12px}.close{background:var(--bg);border:1px solid var(--line);width:35px;height:35px;border-radius:8px}.reader-fallback{padding:8px 20px;font-size:11px;color:var(--muted);border-top:1px solid var(--line)}#pdf-frame{flex:1;width:100%;border:0;background:#e4e4e4;min-height:0}body.reading{overflow:hidden}[hidden]{display:none!important}@media(min-width:1440px){.hero{gap:95px}}@media(max-width:900px){.topbar,main,footer{padding-left:28px;padding-right:28px}.hero{gap:32px;padding-top:48px}.hero-art{min-height:340px}.overview{gap:20px}.overview-note{font-size:10px}.chapter>summary{padding:22px}.chapter-body{padding-left:22px;padding-right:22px}}@media(max-width:680px){.topbar,main,footer{padding-left:20px;padding-right:20px}.topbar{height:86px}.brand{font-size:16px;gap:9px}.brand small{font-size:8px;letter-spacing:1.3px}.brand-icon{height:37px;width:37px;font-size:16px}.nav-link{font-size:11px;gap:8px}.hero{grid-template-columns:1fr;padding:38px 0 30px;gap:30px}h1{font-size:50px;letter-spacing:-2.5px;margin-top:18px}.hero-text>p{font-size:14px;max-width:100%}.hero-art{min-height:220px}.atom{width:65%;height:105%;left:17.5%;top:-2.5%}.art-label{font-size:7px;left:18px;top:18px}.formula-one{top:65px;left:18px}.formula-two{bottom:60px;right:20px}.art-bottom{bottom:16px;left:18px;right:18px;font-size:8px}.overview{gap:16px;flex-wrap:wrap;padding:16px 0;font-size:10px}.overview strong{font-size:16px}.overview-note{display:none}.library{padding-top:32px}.section-heading{align-items:flex-start}.section-heading h2{font-size:26px}.section-heading>p{display:none}.toolbar{flex-direction:column;gap:10px;margin-bottom:20px}.toolbar select{width:100%}.chapter>summary{gap:12px;padding:18px 16px}.chapter-code{height:45px;width:45px;font-size:17px}.chapter-info h3{font-size:16px;line-height:1.4}.chapter-info .subject{font-size:8px}.chapter-info p{font-size:10px}.chapter-body{padding:0 16px 8px}.resource{flex-wrap:wrap;gap:10px;padding:14px 0 18px}.resource-info{flex-basis:calc(100% - 50px)}.resource-title{font-size:12px}.resource-actions{margin-left:46px}.group-title{font-size:9px}.help{padding:20px;margin-bottom:30px;align-items:flex-start}.help p{font-size:11px}footer{flex-wrap:wrap;font-size:9px}footer p{order:3;width:100%}dialog{height:96dvh;max-height:96dvh;border-radius:12px}.reader-bar{padding:12px;align-items:flex-start}.reader-bar h2{font-size:12px}.reader-bar .eyebrow{letter-spacing:1px}.reader-actions .button{font-size:0;padding:8px}.reader-actions .button:after{content:'↓';font-size:16px}.reader-fallback{font-size:10px;padding:8px 12px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}
/* Page de garde : partie du programme et enseignant. */
.hero .part-title{font-size:clamp(34px,4vw,46px);line-height:1.16;letter-spacing:-1.6px}
.hero-part{display:block;font-family:'DM Sans',Arial,sans-serif;font-size:12px;line-height:1.5;letter-spacing:2px;margin-bottom:14px}
.hero-text>.hero-author{font-size:17px;font-weight:600;color:var(--ink);margin-top:-5px;margin-bottom:18px}
.hero-art.hero-photo{min-height:0;aspect-ratio:4/3;background:#12313b;box-shadow:0 18px 40px #152c3614}
.hero-photo img{display:block;width:100%;height:100%;object-fit:cover}
/* Palette de la couverture, accordée aux solutions bleues et roses du visuel. */
:root{--bg:#fbf8f3;--ink:#173642;--muted:#526872;--line:#d9e5e5;--green:#bfe9e9;--soft:#e8f4f3;--accent:#106b78;--rose:#b34f71}
.topbar{border-bottom-color:#d6e5e7}
.brand-icon{background:linear-gradient(145deg,#167888,#104c61);border-color:transparent;color:#fff;box-shadow:0 4px 12px #1265741a}
.brand-icon span{color:#b1f1e5}
.brand i,.footer-brand span{color:var(--rose)}
.nav-link{color:#185c6b;background:#ffffffb3;border:1px solid #d7e7e9;border-radius:999px;padding:9px 14px;align-items:center}
.hero{position:relative;isolation:isolate}
.hero:before{content:'';position:absolute;z-index:-1;inset:28px -24px 22px;border-radius:28px;background:radial-gradient(ellipse at 88% 18%,#f9dce6a3,transparent 48%),linear-gradient(120deg,#e7f4f5 0%,#f4f8f3 48%,#fff1eb 100%);border:1px solid #ffffffc9}
.hero-text>.eyebrow{color:#22616d}
.dot{background:#c05b7c;box-shadow:0 0 0 4px #f6e0e8}
.hero-part{width:fit-content;padding:6px 12px;border:1px solid #b7deda;border-radius:999px;background:#d8efed;color:#115f6b;font-size:11px;letter-spacing:1.7px}
.hero .part-title em{color:#086a77;background:linear-gradient(transparent 76%,#bfe7e4 76%);-webkit-box-decoration-break:clone;box-decoration-break:clone}
.hero .part-title em:after{display:none}
.hero-text>.hero-author{border-left:3px solid #c36c88;padding-left:12px;color:#315b69}
.primary{background:linear-gradient(115deg,#126b7b,#114b60);box-shadow:0 7px 17px #12657526}
.primary:hover{background:linear-gradient(115deg,#0e5968,#103e50);box-shadow:0 8px 20px #12657538}
.hero-art.hero-photo{border:6px solid #fff;box-shadow:0 20px 42px #234e6226}
.overview{background:#ffffffb8;border:1px solid #d9e7e7;border-radius:14px;padding:18px 24px;box-shadow:0 5px 18px #234e6205}
.overview strong{color:#116779}
.chapter{box-shadow:0 6px 22px #234e6208}
.chapter-code{background:#e1f2f2;border-color:#bcdfdf;color:#115f70}
.chapter-info .subject{color:#106875}
.tag{background:#e6f3f1;color:#286760}
.tag.correction{background:#faeaf0;color:#944064}
.read-button{background:#155f71}
.read-button:hover{background:#104c5e}
.pdf-icon{background:#edf5f6;color:#356775}
.help{background:linear-gradient(110deg,#e4f1f1,#f7eced)}
.help-icon{color:#126b78}
.excel-icon{background:#e8f3e9;color:#2d6846}
@media(max-width:680px){.hero:before{inset:14px -12px 8px;border-radius:22px}.hero-part{font-size:10px}.nav-link{padding:7px 10px}.overview{padding:16px}.hero-art.hero-photo{border-width:4px}}

/* Identité du site : une signature plus visible, assortie à la couverture. */
.topbar{position:relative;height:144px;border-bottom:0;gap:24px}
.topbar:after{content:"";position:absolute;bottom:0;left:48px;right:48px;height:1px;background:linear-gradient(90deg,#16788866,#b34f7140 65%,#d6e5e700)}
.brand{gap:18px;font-size:clamp(25px,3vw,32px);letter-spacing:-1px;line-height:1.2}
.brand-copy{display:block}
.brand-title{display:block;white-space:nowrap}
.brand-title>span{color:#126e7d}
.brand i{display:inline-block;margin:0 2px;font-weight:500}
.brand small{font-size:11px;letter-spacing:2.4px;font-weight:600;margin-top:9px}
.brand-icon{position:relative;flex:none;width:68px;height:68px;border-radius:19px;font-size:27px;letter-spacing:-1.6px;gap:2px;background:linear-gradient(140deg,#17889a,#0d4c61);box-shadow:0 8px 22px #12657420}
.brand-icon:after{content:"";position:absolute;inset:6px;border:1px solid #ffffff26;border-radius:14px}
.brand-icon span{transform:none;color:#b8f3e6}
.nav-link{flex:none;font-size:14px;gap:17px;padding:12px 20px;border-color:#c8e1e4;background:#ffffffbf;box-shadow:0 3px 12px #234e6205;transition:background .2s,border-color .2s}
.nav-link>span{display:flex;align-items:center;justify-content:center;width:27px;height:27px;border-radius:50%;background:#e4f2f1;font-size:17px}
.nav-link:hover{background:#edf7f6;border-color:#91c4ca}
.brand:focus-visible,.nav-link:focus-visible{outline:3px solid #167888;outline-offset:5px}
@media(max-width:900px){.topbar:after{left:28px;right:28px}.brand{font-size:26px}.brand small{font-size:10px;letter-spacing:2px}.nav-link{padding:11px 16px;gap:12px}}
@media(max-width:680px){.topbar{height:auto;min-height:150px;padding-top:22px;padding-bottom:20px;flex-wrap:wrap;justify-content:flex-start;gap:16px}.topbar:after{left:20px;right:20px}.brand{width:100%;font-size:26px;gap:14px}.brand-icon{width:60px;height:60px;border-radius:17px;font-size:25px}.brand-icon:after{border-radius:12px}.brand small{font-size:9px;letter-spacing:2px;margin-top:8px}.nav-link{margin-left:74px;font-size:12px;padding:8px 14px;gap:12px}.nav-link>span{width:23px;height:23px;font-size:15px}}
@media(max-width:380px){.brand{font-size:23px;gap:12px}.brand-icon{width:54px;height:54px;font-size:23px}.brand small{font-size:8px;letter-spacing:1.7px}.nav-link{margin-left:66px}}