:root{--paper:#fafafa;--ink:#161616;--muted:#626262;--line:#e0e0e0;--blue:#c70028;--blue-light:#fff0f3;--yellow:#ffbdcb;--youtube-red:#ff0033}
.masthead{border-top:4px solid var(--youtube-red);background:white}
.brand-mark{background:var(--youtube-red)}
.brand-period{color:var(--youtube-red)}
.youtube-context{display:flex;flex-direction:column;gap:7px;flex-shrink:0}
.youtube-context>span{font-size:12px;color:#626262;line-height:1.3}
.youtube-context img{display:block;object-fit:contain;object-position:left center;width:150px;height:auto}
.top-nav a[data-top=books]{color:var(--blue)}
.sidebar{background:#f5f5f5}
.sidebar-heading{gap:10px;align-items:flex-start}
.sidebar-heading .eyebrow{font-size:11px;letter-spacing:.07em;max-width:150px}
.free-tag{background:#161616;color:white}
.lesson-link:hover{background:#eaeaea}
.lesson-link[aria-current=page]{background:#171717;box-shadow:inset 3px 0 var(--youtube-red)}
.lesson-link[aria-current=page] small{color:#c6c6c6}
.course-progress progress::-webkit-progress-value{background:var(--youtube-red)}
.lesson-jumps a:first-child{position:relative}
.lesson-jumps a:first-child::after{content:'';position:absolute;left:0;right:0;bottom:-14px;height:3px;background:var(--youtube-red)}
.result-panel{background:#181818;border-top:4px solid var(--youtube-red)}
.result-panel .eyebrow{color:#ffb3c2}
.result-caption,.result-prose{color:#dedede}
.result-note{background:#ffffff0b;border-left-color:var(--youtube-red)}
.result-note b{color:#ffb3c2}
.bar-fill{background:var(--youtube-red)}
.bar-fill.muted{background:#a8a8a8}
.button.blue{background:var(--blue);border-color:var(--blue)}
.button.blue:hover{background:#a40021;border-color:#a40021}
.button:hover{background:#353535}
.button.secondary:hover{background:#ededed}
.quiz{background:#f1f1f1}
.quiz-option{background:#fff}
.book-callout{grid-template-columns:132px 1fr;background:#161616;border:1px solid #2a2a2a;padding:28px 32px;gap:30px;color:#fff}
.book-callout .eyebrow{color:#ffb3c2}
.book-callout p{color:#d0d0d0}
.book-callout a{color:#fff;text-decoration-color:#ff0033;text-decoration-thickness:2px}
.book-callout img{box-shadow:5px 8px 22px #0009}
.book-grid{gap:42px 28px}
.cover-link{background:#171717;padding:18px 21px;border-top:3px solid var(--youtube-red)}
.cover-link img{object-fit:contain;box-shadow:4px 9px 16px #0008}
.cover-link:hover img{transform:translateY(-4px)}
.book-card h2{font-weight:600}
.book-card .eyebrow{color:var(--blue)}
.cover-view{font-size:13px;color:var(--blue);font-weight:600;text-underline-offset:4px}
.availability{background:white}
.edition-note{background:#fff;border-left:3px solid var(--youtube-red)}
.download-box{background:#fce9ed;border-left:3px solid var(--youtube-red)}
footer{background:#fff}
@media(max-width:1100px){.masthead{gap:24px}.top-nav{gap:20px}.youtube-context{padding-left:22px}.book-callout{padding:24px;gap:25px}}
@media(max-width:820px){.youtube-context{padding:0;align-items:flex-start;margin-left:auto}.sidebar{padding-bottom:0}.sidebar-heading .eyebrow{max-width:none}.lesson-link[aria-current=page]{box-shadow:inset 0 -3px var(--youtube-red)}.top-nav a{white-space:nowrap}}
@media(max-width:570px){.youtube-context>span{font-size:11px}.youtube-context img{width:120px}.masthead{gap:14px;padding-left:20px;padding-right:20px}.brand{font-size:17px;gap:10px}.book-callout{grid-template-columns:100px 1fr;padding:22px 18px;gap:20px}.book-callout h3{font-size:23px}.cover-link{padding:0;border:0;background:none}.book-card{grid-template-columns:128px 1fr;gap:19px}.book-card h2{font-size:23px}.book-card ul{padding-left:15px}.book-card .eyebrow{font-size:11px}.book-card .button{font-size:13px;line-height:1.5}.book-card .availability{font-size:11px;display:inline-block}.book-actions .button{width:100%}.book-grid{gap:32px}.result-panel{border-top-width:3px}}
@media(max-width:370px){.brand{font-size:15px}.brand-mark{width:34px;height:37px;font-size:22px}.youtube-context img{width:86px}.youtube-context>span{font-size:10px}.book-card{grid-template-columns:106px 1fr;gap:15px}.book-callout{grid-template-columns:84px 1fr}}
@media print{.result-panel{background:#fff;color:#111;border:1px solid #ccc}.result-panel *{color:#111!important}.sidebar,.masthead,.book-callout{display:none}}