/* Visual direction 02 — ivory chalk on an ink-black mathematics board. */
:root{--bg:#081518;--panel:#112124;--text:#f1ead8;--muted:#a8b2ac;--blue:#ded0ac;--line:#d5c9a52c}body{background:#081518;color:var(--text)}body:before{content:'';position:fixed;inset:0;pointer-events:none;z-index:20;opacity:.032;background-image:url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.83' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Cpath fill='%23fff' filter='url(%23n)' opacity='.7' d='M0 0h180v180H0z'/%3E%3C/svg%3E")}header{border-color:#d5c9a523}.logo-mark{background:none;border:1px solid #e5d8b8;color:#eee5d0;border-radius:50%;transform:none;box-shadow:inset 0 0 0 3px #081518,inset 0 0 0 4px #d9cda568;font-family:Georgia,serif}.logo-mark span{color:#ded1af}.logo b{font-family:Georgia,serif;font-weight:400;letter-spacing:0}.logo b span{color:#c8c9b9}nav{color:#b7bdb2}.button{background:#e4d8ba;color:#132023;border-color:#e4d8ba;border-radius:5px;box-shadow:0 4px 20px #0002}.button:hover{background:#f6ecd5;color:#0a171a}.button.small{background:transparent;border-color:#d8cba35c;color:#ede2cb}.button.small:hover{background:#dbcea615}.hero{min-height:760px}.hero:before{background:radial-gradient(ellipse at 50% 40%,#28413b3a,transparent 63%);inset:0}.hero-grid{background:none}.hero-copy{padding-top:85px}.eyebrow{color:#b9b8a3;letter-spacing:2.2px}.dot,.tiny-dot{background:#ddcc9d;box-shadow:none}h1,h2{font-family:Georgia,'Times New Roman',serif;font-weight:400}h1{font-size:clamp(48px,4.9vw,73px);letter-spacing:-2.8px;line-height:1.12}.accent{color:#e1d0a6}h1 .accent{font-style:italic}h1 .accent:after{border-color:#cbbd93;border-width:1px;bottom:-10px}.hero-copy p{color:#aeb9b2}.micro{color:#8e9c95}.play{border-color:#d5c9a554}.text-link{color:#ded8c6}.chalk-board{position:absolute;inset:0;width:100%;height:100%;color:#e7ddbd;opacity:.23;z-index:-1;pointer-events:none}.orbit{display:none}.formula{color:#d9cba561;font-size:19px}.f1{top:44px;left:25%;transform:rotate(-7deg)}.f2{right:26%;top:49px;transform:rotate(7deg)}.teacher-portrait{bottom:64px;height:480px}.teacher-portrait img{filter:drop-shadow(0 0 24px #01090b50);mask-image:linear-gradient(#000 78%,transparent 100%)}.portrait-label{background:#0b1b1deb;border-color:#d9cba545;color:#e5dfce;border-radius:4px;font-size:10px}.floating-note{background:#102225eb;border-color:#d9cba53d;border-radius:6px;color:#e7deca;box-shadow:0 8px 30px #0002}.floating-note>span{background:#d3c18f15;color:#dcca9c;border-radius:50%;border:1px solid #d9cba52b}.floating-note small{color:#9daaa2}.scroll{color:#a0aaa0}.subject-bar{background:#101f20;color:#b9bba9;border-color:#cabb9433}.subject-bar i{color:#c3b38b}.muted{color:#9ba89f}.feature{background:linear-gradient(145deg,#122528,#0c1b1e);border-color:#d6c89e33;border-radius:7px}.feature-icon{background:transparent;border-color:#d5c9a548;color:#d5c7a1;border-radius:50%;font-family:Georgia,serif}.feature h3{color:#eae1cc}.mini-task{background:#081719;border-color:#b9c1a62b;border-radius:4px;color:#a4b1a7}.mini-task b{color:#e1d9c3}.segments i{background:#c5b588}.segments i:nth-child(n+5){background:#293e3b}.book{background:#243f3c;border-left-color:#38534a;box-shadow:8px 10px 25px #0005;border-right:1px solid #d0c29b55}.book small,.book>span{color:#d9cca9}.book strong{font-family:Georgia,serif;font-weight:400}.book-tag{background:#142927;border-color:#d9cba553;color:#e0d6be}.book-tag span{color:#ded0a9}.chart div{background:linear-gradient(#d7c99f,#546d5d)}.chart{border-color:#a2ac8c40}.chart-caption{color:#a7b2a2}.practice-copy h2 .accent{font-style:italic}.practice-points{color:#c4cabb}.practice-points span:first-letter{color:#dfd0a3}.hand-note{color:#d9c795}.quiz{background:#102225;border-color:#d1c39666;border-radius:8px;box-shadow:0 0 0 6px #081518,0 0 0 7px #d1c39625,0 20px 80px #0003}.quiz-top,.quiz-topic{color:#b6b9a5}.quiz-progress{background:#2a3e3a}.quiz-progress i{background:#cfbd8d}.answer{background:#0b1a1d;border-color:#b7bea140;border-radius:4px;color:#e4deca}.answer:hover{border-color:#e2d1a3}.answer[aria-pressed=true]{background:#39483a;border-color:#dfd0a3}.answer.correct{background:#1e473c;border-color:#8cc8a7}.answer.wrong{background:#4c3030;border-color:#d8a398}.feedback{color:#c5cbbb}.hint-button{color:#c5c9b4}.demo-note{color:#9da997}.equation{color:#f0e6cb;font-style:italic}.teacher-message{border-color:#d6c89e38}.quote-mark{color:#d4c294}blockquote{font-family:Georgia,serif;font-size:27px;color:#e0dac5}.team-signature span{color:#a0aca0}.avatars img{background:#29413b;border-color:#081518}.steps article{border-color:#d5c9a540}.steps article>span{font-family:Georgia,serif;font-style:italic;color:#d9c693;font-size:22px}.steps p{color:#a8b2ac}summary:after{color:#d7c598}details p{color:#b0b9ac}.final-cta{border-color:#d5c9a53b;background:radial-gradient(ellipse at 50% 100%,#29473a60,transparent 73%)}.final-cta h2 .accent{font-style:italic}.final-cta p,footer p,footer>span{color:#a2ad9f}dialog{background:#112427;border-color:#d7c79b66;color:#f1ead8;border-radius:8px}dialog>p,.login-preview p{color:#b7c0b2}.login-preview{background:#081719;border-color:#d6c89e33;border-radius:4px}.login-preview>span,.close{color:#d8c89e}button:focus-visible,a:focus-visible,summary:focus-visible{outline-color:#e6d5a2}.skip{background:#d5c396;color:#081518}::selection{background:#d3c295;color:#0b1c1d}
@media(min-width:1101px){.note-left{left:24%;bottom:175px}.note-right{right:23%;bottom:164px}}
@media(max-width:1100px){.hero{min-height:750px}.hero-copy{padding-top:65px}h1{font-size:57px}.teacher-portrait{height:360px;bottom:50px}.note-left{left:27%;bottom:126px}.note-right{right:26%;bottom:93px}.floating-note{font-size:10px;padding:10px}.floating-note small{font-size:8px}.formula{font-size:15px}.chalk-board{width:130%;max-width:none;left:-15%}}
@media(max-width:760px){.hero{min-height:790px}.hero-copy{padding:48px 18px 0}h1{font-size:clamp(39px,8.1vw,58px);letter-spacing:-1.5px}.hero-copy p{color:#b1bcb4}.teacher-portrait{height:340px;bottom:39px}.portrait-label{font-size:8px}.chalk-board{width:210%;left:-55%;opacity:.17}.formula{font-size:15px;top:473px}.f1{left:9%}.f2{right:9%}h2{font-size:34px}.feature{border-radius:6px}.practice-copy h2{font-size:36px}.quiz{margin:0 4px}.final-cta h2{font-size:33px}blockquote{font-size:23px}}
@media(max-width:380px){.hero{min-height:754px}h1{font-size:39px}.teacher-portrait{height:300px}.portrait-label{font-size:7px}.formula{top:458px}}
.portrait-label{backdrop-filter:none}
@media(max-width:760px){.chalk-board{opacity:.11}}

.library-open{display:inline-block;margin:0 0 12px;font-size:12px;text-decoration:underline;text-underline-offset:4px;color:#e3d4aa}