:root{
  --bg:#071018;--bg-soft:#0b1620;--panel:#0f1e29;--panel-2:#132735;
  --text:#edf5f7;--muted:#9fb4bf;--blue:#00a6d9;--yellow:#f3c400;
  --line:#26404d;--ok:#77d6a5;--danger:#ff8a7a;--max:1180px
}
*{box-sizing:border-box} html{scroll-behavior:smooth}
body{margin:0;background:
radial-gradient(circle at 15% 0%,rgba(0,166,217,.08),transparent 28rem),
radial-gradient(circle at 85% 10%,rgba(243,196,0,.05),transparent 24rem),var(--bg);
color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.6}
a{color:inherit}.container{width:min(var(--max),calc(100% - 2rem));margin-inline:auto}
.skip-link{position:absolute;left:-9999px}.skip-link:focus{left:1rem;top:1rem;background:var(--yellow);color:#000;padding:.6rem .8rem;z-index:99}
.site-header{position:sticky;top:0;z-index:30;backdrop-filter:blur(14px);background:rgba(7,16,24,.88);border-bottom:1px solid rgba(255,255,255,.07)}
.nav{min-height:78px;display:flex;align-items:center;justify-content:space-between;gap:1rem}
.brand{display:flex;align-items:center;gap:.9rem;text-decoration:none}.brand img{width:58px}.brand-copy strong{display:block;letter-spacing:.08em;font-size:.86rem}.brand-copy span{display:block;color:var(--muted);font-size:.8rem}
.nav-links{display:flex;gap:.35rem;flex-wrap:wrap}.nav-links a{text-decoration:none;color:var(--muted);padding:.45rem .68rem;border-radius:.45rem}.nav-links a:hover,.nav-links a.active{background:var(--panel);color:var(--text)}
.hero{padding:6rem 0 4.5rem;border-bottom:1px solid var(--line)}.hero-grid{display:grid;grid-template-columns:1.35fr .65fr;gap:3rem;align-items:end}
.eyebrow{color:var(--yellow);text-transform:uppercase;letter-spacing:.16em;font-weight:800;font-size:.75rem}
h1,h2,h3{line-height:1.15;margin-top:0}h1{font-size:clamp(2.6rem,6vw,5.8rem);letter-spacing:-.055em;margin:.4rem 0 1.2rem;max-width:14ch}h2{font-size:clamp(1.8rem,3vw,3rem);letter-spacing:-.035em;margin-top:3.5rem}h3{font-size:1.25rem}
.lead{font-size:clamp(1.05rem,2vw,1.3rem);color:#c5d5dc;max-width:62ch}.section{padding:4rem 0}.section-intro{max-width:70ch;color:var(--muted);margin-bottom:2rem}
.hero-mark{min-height:260px;border:1px solid var(--line);border-radius:1.1rem;position:relative;overflow:hidden;background:linear-gradient(145deg,var(--panel),#071018)}
.hero-mark:before,.hero-mark:after{content:"";position:absolute;border:4px solid}.hero-mark:before{width:120px;height:120px;border-color:var(--blue) transparent transparent var(--blue);left:2rem;bottom:2rem;transform:rotate(-45deg)}
.hero-mark:after{width:90px;height:90px;border-color:var(--yellow) var(--yellow) transparent transparent;right:2rem;top:2rem}
.terminal{position:absolute;inset:auto 1.5rem 1.5rem 1.5rem;padding:1rem;background:#050a0e;border:1px solid #20303a;border-radius:.75rem;font-family:Consolas,monospace;color:#b9d8e4;font-size:.85rem}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1rem}.two-col{display:grid;grid-template-columns:1fr 1fr;gap:1.2rem}
.card{display:block;text-decoration:none;background:linear-gradient(180deg,var(--panel),#0a151d);border:1px solid var(--line);border-radius:.9rem;padding:1.4rem;min-height:190px;transition:.2s}.card:hover{transform:translateY(-3px);border-color:var(--blue)}.card p{color:var(--muted);margin-bottom:0}.num{font-family:monospace;color:var(--yellow);font-size:.8rem}.pill{display:inline-block;margin-top:.8rem;padding:.25rem .55rem;border:1px solid var(--line);border-radius:999px;color:var(--muted);font-size:.78rem}
.btn{display:inline-flex;text-decoration:none;background:var(--yellow);color:#0b1014;font-weight:800;padding:.72rem 1rem;border-radius:.55rem}.btn.secondary{background:transparent;color:var(--text);border:1px solid var(--line)}.actions{display:flex;gap:.7rem;flex-wrap:wrap;margin-top:1.5rem}
.topic-layout{display:grid;grid-template-columns:260px minmax(0,1fr);gap:2.5rem;align-items:start}.topic-nav{position:sticky;top:100px;background:var(--panel);border:1px solid var(--line);border-radius:.8rem;padding:1rem}.topic-nav a{display:block;text-decoration:none;color:var(--muted);padding:.36rem .3rem}.topic-nav a:hover{color:var(--yellow)}
.content p,.content li{color:#c1d1d8}.breadcrumbs{padding-top:2rem;color:var(--muted);font-size:.9rem}.breadcrumbs a{color:var(--muted)}
pre{overflow:auto;background:#03080c;border:1px solid #20303a;padding:1rem;border-radius:.75rem;color:#c8e2ec}code{font-family:"SFMono-Regular",Consolas,monospace}
.callout,.objectives,.teacher-note,.solution{padding:1rem 1.2rem;border-radius:.7rem;background:var(--panel);border:1px solid var(--line);margin:1.2rem 0}.callout{border-left:4px solid var(--blue)}.callout.yellow{border-left-color:var(--yellow)}
.lab,.breakfix{margin:1.5rem 0;border-radius:.8rem;padding:1.2rem}.lab{border:1px solid rgba(243,196,0,.45);background:rgba(243,196,0,.06)}.lab h3{color:var(--yellow)}.breakfix{border:1px solid rgba(0,166,217,.5);background:rgba(0,166,217,.07)}.breakfix h3{color:#68d3f5}
.teacher-note{border-left:4px solid #a78bfa}.teacher-note h3{color:#c4b5fd}.solution{border-left:4px solid var(--ok)}details summary{cursor:pointer;font-weight:800}
.boot-chain{display:flex;align-items:stretch;gap:.5rem;flex-wrap:wrap;margin:1.5rem 0}.boot-step{flex:1 1 125px;background:var(--panel);border:1px solid var(--line);padding:1rem;border-radius:.7rem;text-align:center}.boot-step b{display:block;color:var(--yellow);font-family:monospace;font-size:.78rem;margin-bottom:.35rem}.arrow{align-self:center;color:var(--blue);font-weight:900}
.topic-footer-nav{display:flex;justify-content:space-between;gap:1rem;margin-top:3rem;padding-top:1.5rem;border-top:1px solid var(--line)}.footer{border-top:1px solid var(--line);padding:2.5rem 0;color:var(--muted);font-size:.9rem}
@media(max-width:900px){.hero-grid,.topic-layout,.two-col{grid-template-columns:1fr}.grid{grid-template-columns:1fr 1fr}.topic-nav{position:static}}
@media(max-width:650px){.nav{align-items:flex-start;padding:.8rem 0;flex-direction:column}.grid{grid-template-columns:1fr}.hero{padding-top:3.5rem}h1{font-size:3rem}.arrow{display:none}}

/* Kapitel 1: Abbildungen */
.lesson-figure{
    margin:1.6rem 0 2rem;
    padding:1rem;
    background:linear-gradient(180deg,var(--panel),#0a151d);
    border:1px solid var(--line);
    border-radius:.9rem;
}
.lesson-figure img{
    display:block;
    width:100%;
    max-height:560px;
    object-fit:contain;
    border-radius:.55rem;
    background:#050a0e;
}
.lesson-figure.wide img{
    max-height:650px;
}
.lesson-figure figcaption{
    margin-top:.75rem;
    color:var(--muted);
    font-size:.82rem;
    line-height:1.45;
}


/* Interaktive Fragen unter Befehlen */
.command-quiz{
    margin:.7rem 0 1.6rem;
}
.command-quiz-trigger{
    display:inline-flex;
    align-items:center;
    gap:.55rem;
    border:1px solid var(--line);
    border-radius:.55rem;
    padding:.55rem .8rem;
    background:rgba(0,166,217,.06);
    color:var(--text);
    cursor:pointer;
    font:inherit;
}
.command-quiz-trigger:hover{
    border-color:var(--blue);
}
.command-quiz-trigger code{
    color:var(--yellow);
}
.command-quiz-icon{
    display:grid;
    place-items:center;
    width:1.45rem;
    height:1.45rem;
    border-radius:50%;
    background:var(--blue);
    color:#041016;
    font-weight:900;
}
.command-quiz-panel{
    margin-top:.75rem;
    padding:1rem;
    border:1px solid var(--line);
    border-radius:.8rem;
    background:linear-gradient(180deg,var(--panel),#0a151d);
}
.command-quiz-question{
    margin:.1rem 0 1rem;
    color:var(--text)!important;
    font-weight:750;
}
.command-quiz-answers{
    display:grid;
    grid-template-columns:1fr 1fr;
    gap:.7rem;
}
.command-quiz-answer{
    display:flex;
    align-items:flex-start;
    gap:.65rem;
    min-height:58px;
    padding:.75rem;
    text-align:left;
    border:1px solid var(--line);
    border-radius:.65rem;
    background:#08131b;
    color:var(--text);
    cursor:pointer;
    font:inherit;
}
.command-quiz-answer:not(:disabled):hover{
    border-color:var(--blue);
    transform:translateY(-1px);
}
.command-quiz-answer:disabled{
    cursor:default;
}
.command-quiz-letter{
    flex:0 0 auto;
    display:grid;
    place-items:center;
    width:1.7rem;
    height:1.7rem;
    border-radius:.4rem;
    background:var(--panel-2);
    color:var(--yellow);
    font-family:monospace;
    font-weight:800;
}
.command-quiz-answer.is-correct{
    border-color:rgba(119,214,165,.8);
    background:rgba(119,214,165,.08);
}
.command-quiz-answer.is-wrong{
    border-color:rgba(255,138,122,.8);
    background:rgba(255,138,122,.08);
}
.command-quiz-feedback{
    min-height:1.6rem;
    margin-top:.9rem;
    font-weight:800;
}
.command-quiz-feedback.is-correct{color:var(--ok)}
.command-quiz-feedback.is-wrong{color:var(--danger)}
.command-quiz-explanation{
    margin-top:.4rem;
    color:var(--muted);
}
.command-quiz-explanation strong{
    color:var(--text);
}
.command-quiz-reset{
    margin-top:.8rem;
    border:0;
    padding:0;
    background:transparent;
    color:var(--blue);
    cursor:pointer;
    font:inherit;
    text-decoration:underline;
}
@media(max-width:650px){
    .command-quiz-answers{grid-template-columns:1fr}
}