:root{
      --ink:#181719;
      --muted:#5f6168;
      --soft:#f6f2ed;
      --soft-2:#ebe4dc;
      --line:#ddd5cd;
      --red:#a61116;
      --red-dark:#7d0d12;
      --night:#171417;
      --paper:#fff;
    }
    *{box-sizing:border-box}
    html{scroll-behavior:smooth}
    body{margin:0;background:var(--paper);color:var(--ink);font-family:Inter,Arial,sans-serif;line-height:1.5}
    a{color:inherit}

    .shell-topbar{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.96);backdrop-filter:blur(14px);border-bottom:1px solid var(--line,#ded8d1)}
    .shell-topbar__inner{max-width:1180px;margin:0 auto;min-height:72px;padding:0 24px;display:flex;align-items:center;justify-content:space-between;gap:24px}
    .shell-brand{display:inline-flex;align-items:center;gap:9px;color:var(--ink,#171719);font-weight:900;letter-spacing:.08em;text-transform:uppercase;font-size:15px;text-decoration:none;white-space:nowrap}
    .shell-brand::before{content:"";display:block;width:22px;height:22px;background:linear-gradient(135deg,var(--red,#a61116) 0 49%,transparent 50%),#171417;border-radius:4px}
    .shell-nav{display:flex;align-items:center;gap:18px;min-width:0;color:#4d4e52;font-size:14px}
    .shell-nav a{display:inline-flex;align-items:center;color:inherit;text-decoration:none;white-space:nowrap}
    .shell-nav a[aria-current="page"]{color:var(--red,#a61116);font-weight:800}
    .shell-action{display:inline-flex;align-items:center;justify-content:center;min-height:38px;padding:0 13px;border-radius:6px;background:var(--red,#a61116);color:#fff!important;font-weight:800}
    .shell-footer{background:#161417;color:#fff;padding:52px 24px}
    .shell-footer__inner{max-width:1180px;margin:0 auto;display:grid;grid-template-columns:1.25fr repeat(4,minmax(0,1fr));gap:32px}
    .shell-footer__brand strong{display:block;font-size:18px;text-transform:uppercase;letter-spacing:.08em}
    .shell-footer__brand p,.shell-footer__cta p{margin:12px 0 0;color:#cfc8c5;font-size:14px;line-height:1.55}
    .shell-footer h3{margin:0 0 12px;color:#fff;font-size:13px;text-transform:uppercase;letter-spacing:.08em}
    .shell-footer a{display:block;color:#d9d4d0;text-decoration:none;font-size:14px;line-height:1.35;margin-bottom:9px}
    .shell-footer a:hover{color:#fff}
    .shell-footer__cta a{display:inline-flex;margin-top:14px;margin-bottom:0;padding:10px 13px;border-radius:6px;background:var(--red,#a61116);color:#fff;font-weight:800}
    @media (max-width:920px){
      .shell-topbar{position:static}
      .shell-topbar__inner{min-height:0;padding:16px 18px;align-items:flex-start;flex-direction:column}
      .shell-nav{width:100%;flex-wrap:wrap;gap:12px}
      .shell-action{width:100%;max-width:320px}
      .shell-footer__inner{grid-template-columns:1fr;gap:24px}
    }

    .course-page{overflow:hidden}
    .section{padding:74px 24px}
    .section__inner{max-width:1180px;margin:0 auto}
    .eyebrow{margin:0 0 14px;color:var(--red);font-size:13px;font-weight:900;letter-spacing:.16em;text-transform:uppercase}
    .section-title{margin:0;font-size:clamp(34px,5vw,64px);line-height:1.04;letter-spacing:0}
    .section-lead{max-width:780px;margin:18px 0 0;color:#4d4f56;font-size:19px;line-height:1.58}
    .hero{padding:38px 24px 54px;background:linear-gradient(124deg,#171417 0%,#1c1a1e 58%,#2d1418 100%);color:#fff}
    .hero__inner{max-width:1180px;margin:0 auto;display:grid;grid-template-columns:minmax(0,1fr) minmax(310px,.42fr);gap:34px;align-items:end}
    .breadcrumbs{display:flex;gap:10px;align-items:center;margin-bottom:28px;color:#e9c7c3;font-size:14px}
    .breadcrumbs a{text-decoration:none;color:#fff;font-weight:800}
    .hero h1{max-width:860px;margin:0;font-size:clamp(42px,5.7vw,74px);line-height:.99;letter-spacing:0}
    .hero__lead{max-width:780px;margin:20px 0 0;color:#e7dfdc;font-size:20px;line-height:1.54}
    .hero__actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:26px}
    .btn{display:inline-flex;align-items:center;justify-content:center;min-height:48px;padding:0 18px;border-radius:6px;font-weight:900;text-decoration:none}
    .btn--primary{background:var(--red);color:#fff}
    .btn--ghost{border:1px solid rgba(255,255,255,.42);color:#fff}
    .hero-card{padding:24px;background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.16);border-left:5px solid var(--red);border-radius:8px}
    .hero-card h2{margin:0;font-size:26px;line-height:1.12}
    .hero-card p{margin:12px 0 0;color:#d9d1cd}
    .hero-stats{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:22px}
    .hero-stats div{min-height:78px;padding:14px;background:#242127;border-radius:6px}
    .hero-stats strong{display:block;font-size:32px;line-height:1;color:#fff}
    .hero-stats span{display:block;margin-top:8px;color:#d0c8c4;font-size:13px;line-height:1.35}
    .quick-nav{background:#fff;border-bottom:1px solid var(--line)}
    .quick-nav__inner{max-width:1180px;margin:0 auto;padding:14px 24px;display:flex;gap:10px;overflow:auto}
    .quick-nav a{display:inline-flex;align-items:center;min-height:38px;padding:0 13px;border:1px solid var(--line);border-radius:999px;color:#4e5056;text-decoration:none;font-weight:800;white-space:nowrap}
    .quick-nav a:hover{border-color:var(--red);color:var(--red)}
    .course-use{background:var(--soft)}
    .note-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px;margin-top:32px}
    .note-card{min-height:210px;padding:22px;background:#fff;border:1px solid var(--line);border-radius:8px}
    .note-card h3{margin:0;font-size:24px;line-height:1.12}
    .note-card p{margin:14px 0 0;color:#55575d}
    .author-grid{display:grid;grid-template-columns:minmax(0,.72fr) minmax(320px,.48fr);gap:22px;margin-top:32px}
    .author-main{padding:32px;background:#fff;border:1px solid var(--line);border-radius:8px}
    .author-main h3{margin:0;font-size:34px;line-height:1.08}
    .author-main p{margin:14px 0 0;color:#4e5056;font-size:18px}
    .author-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:20px}
    .author-tags span{display:inline-flex;min-height:34px;align-items:center;padding:0 11px;border-radius:999px;background:var(--soft);border:1px solid var(--line);font-weight:800;color:#57595f}
    .author-contact{padding:30px;background:var(--night);color:#fff;border-radius:8px}
    .author-contact h3{margin:0;font-size:28px;line-height:1.1}
    .author-contact p{margin:14px 0 0;color:#d9d1cd}
    .author-contact a{display:inline-flex;align-items:center;justify-content:center;min-height:46px;margin-top:18px;padding:0 16px;background:var(--red);color:#fff;border-radius:6px;text-decoration:none;font-weight:900}
    .stage-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px;margin-top:30px}
    .stage-card{padding:22px;background:var(--night);color:#fff;border-radius:8px}
    .stage-card span{display:block;color:#f0c6c3;font-size:13px;font-weight:900;letter-spacing:.12em}
    .stage-card h3{margin:18px 0 0;font-size:23px;line-height:1.12}
    .stage-card p{margin:14px 0 0;color:#d9d1cd;font-size:15px}
    .lesson-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin-top:28px}
    .lesson-card{min-height:118px;padding:20px;background:#fff;border:1px solid var(--line);border-radius:8px;text-decoration:none;display:grid;grid-template-columns:48px minmax(0,1fr);gap:16px;align-items:start}
    .lesson-card__number{display:flex;align-items:center;justify-content:center;width:48px;height:48px;background:var(--night);border-radius:6px;color:#fff;font-size:20px;font-weight:900}
    .lesson-card__body strong{display:block;font-size:20px;line-height:1.22}
    .lesson-card__body small{display:block;margin-top:10px;color:var(--red);font-weight:900}
    .lesson-card:hover{border-color:var(--red)}
    .help{background:var(--soft)}
    .help-grid{display:grid;grid-template-columns:minmax(0,.85fr) minmax(320px,.5fr);gap:22px;align-items:stretch}
    .help-panel{padding:34px;background:#fff;border:1px solid var(--line);border-radius:8px}
    .help-panel h2{margin:0;font-size:clamp(34px,4.4vw,58px);line-height:1.05}
    .help-panel p{margin:18px 0 0;color:#4e5056;font-size:18px}
    .help-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:22px}
    .help-actions a{display:inline-flex;align-items:center;justify-content:center;min-height:46px;padding:0 16px;border-radius:6px;text-decoration:none;font-weight:900}
    .help-actions a:first-child{background:var(--red);color:#fff}
    .help-actions a:last-child{border:1px solid var(--line);color:var(--red)}
    .help-side{padding:30px;background:var(--night);color:#fff;border-radius:8px}
    .help-side h3{margin:0;font-size:28px;line-height:1.08}
    .help-side p{margin:14px 0 0;color:#d9d1cd}
    .help-side a{display:block;margin-top:14px;color:#fff;font-weight:900;text-decoration:none}
    .source-note{margin:22px 0 0;color:#8a817c;font-size:13px}
    @media (max-width:1080px){
      .hero__inner,.author-grid,.help-grid{grid-template-columns:1fr}
      .note-grid,.stage-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
    }
    @media (max-width:720px){
      .section{padding:52px 18px}
      .hero{padding:42px 18px 48px}
      .hero h1{font-size:39px;line-height:1.04}
      .hero__lead,.section-lead{font-size:18px}
      .breadcrumbs{margin-bottom:32px}
      .hero__actions{gap:10px}
      .help-actions{flex-direction:column}
      .btn{min-height:44px;padding:0 13px}
      .btn--primary{flex:1 1 100%}
      .btn--ghost{flex:1 1 calc(50% - 5px)}
      .help-actions a{width:100%}
      .hero-card{padding:18px}
      .hero-card h2{font-size:22px}
      .hero-card p{display:none}
      .hero-stats{grid-template-columns:repeat(2,minmax(0,1fr))}
      .hero-stats div{min-height:68px;padding:12px}
      .hero-stats strong{font-size:26px}
      .hero-stats span{font-size:12px}
      .note-grid,.stage-grid,.lesson-grid{grid-template-columns:1fr}
      .quick-nav__inner{padding:12px 18px}
      .note-card,.lesson-card{min-height:0}
      .author-main,.author-contact,.help-panel,.help-side{padding:24px}
    }