@font-face{font-family:Inter;src:local('Inter')}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:#f7f9fd;color:#162843;font:16px/1.55 Inter,system-ui,-apple-system,Segoe UI,sans-serif}button,input,select{font:inherit}button,a,input{touch-action:manipulation}a{color:inherit;text-decoration:none}button{cursor:pointer}button:disabled{cursor:wait;opacity:.6}:focus-visible{outline:3px solid #daae00;outline-offset:4px}.skip{position:absolute;top:-60px;background:#ffd700;padding:10px}.skip:focus{top:0;z-index:20}header{height:96px;border-bottom:1px solid #e3eaf5;display:flex;align-items:center;justify-content:space-between;padding:0 max(5vw,20px);gap:24px;background:white}.brand{display:flex;align-items:center;gap:12px;font-size:24px;font-weight:800;letter-spacing:-.7px}.brand img{width:58px;height:58px;object-fit:contain}.brand b{color:#0074e8}.brand small{display:block;font-size:10px;letter-spacing:2px;font-weight:600;color:#536784}nav{display:flex;gap:30px;font-size:14px;font-weight:650}nav a{padding:10px 0}nav a.active{color:#006fdc;border-bottom:2px solid #007fff}.button{display:inline-flex;align-items:center;justify-content:center;gap:10px;background:#0071e3;color:white;border:1px solid #0071e3;border-radius:10px;padding:12px 22px;font-weight:650;font-size:14px;min-height:46px}.button:hover{background:#005ebf}.button.outline{background:white;color:#1b365d;border-color:#d5dfed}.button.outline:hover{background:#eef5ff}.button.gold{background:#ffd700;color:#172941;border-color:#ffd700}.button.gold:hover{background:#efc900}.button.small{padding:9px 15px;min-height:40px}.wide{width:100%}.text-button{border:0;background:none;color:#006fdc;padding:10px}.hero{max-width:1240px;margin:auto;padding:70px 30px 60px;display:grid;grid-template-columns:1.2fr 1fr;align-items:center;gap:70px}.eyebrow{display:block;font-size:11px;letter-spacing:2px;font-weight:800;color:#0067ca}.hero h1{font-size:clamp(38px,4.7vw,62px);line-height:1.12;letter-spacing:-2.3px;margin:20px 0 24px;font-weight:800}.hero h1 em{font-style:normal;color:#0075eb}.hero p{max-width:520px;color:#58708c;font-size:17px}.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:28px}.hero-note{font-size:12px!important;margin-top:18px}.study-card{background:#112e58;color:white;padding:32px;border-radius:24px;box-shadow:0 24px 60px #163b6422;position:relative;transform:rotate(2deg)}.study-card:before{content:"";position:absolute;inset:13px -14px -14px 14px;border:1px solid #c7d7ed;border-radius:24px;z-index:-1}.study-top{display:flex;justify-content:space-between;font-size:11px;letter-spacing:1px;color:#bbd0ec}.study-top span:last-child{color:#ffd700}.study-card h3{font-size:24px;margin:25px 0 18px;font-weight:550}.sample{font-size:17px;line-height:2}.sample-answer{border:1px solid #496285;border-radius:10px;padding:11px 16px;margin-top:10px;display:flex;justify-content:space-between}.sample-answer.correct{border-color:#ffd700;background:#ffd70013}.sample-footer{display:flex;align-items:center;gap:12px;margin-top:24px;font-size:11px;color:#bfd0e9}.sample-line{height:4px;flex:1;border-radius:10px;background:#385375}.sample-line:before{content:"";display:block;width:65%;height:100%;background:#ffd700}.benefits{display:flex;justify-content:center;gap:65px;border-block:1px solid #e3eaf5;background:#fff;padding:22px 25px;font-size:13px;color:#536784}.benefits b{color:#223c5e}.section{max-width:1180px;margin:auto;padding:48px 20px 60px}.section-heading{display:flex;justify-content:space-between;gap:20px;align-items:end;margin-bottom:25px}h2{font-size:30px;letter-spacing:-1px;margin:8px 0}h3{line-height:1.3}.muted{color:#64768d;font-size:14px}.section-heading p{margin:4px 0}.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}.subject{border:1px solid #e2e9f3;background:white;border-radius:15px;padding:22px;display:flex;flex-direction:column;align-items:start;text-align:left;transition:transform .16s,box-shadow .16s;min-height:190px;position:relative}.subject:hover{transform:translateY(-3px);box-shadow:0 9px 24px #243f6211;border-color:#92beed}.subject img{width:64px;height:64px;object-fit:contain;border-radius:12px;margin-bottom:15px}.subject h3{margin:0 25px 8px 0;font-size:16px}.subject p{font-size:12px;color:#6c809a;margin:0}.subject .arrow{position:absolute;right:20px;bottom:20px;color:#0071e3}.tag{font-size:10px;padding:3px 7px;background:#fff3b3;border-radius:5px;color:#6c5400;margin-bottom:10px}.search-bar{display:flex;gap:10px;flex-wrap:wrap;margin:25px 0}.search-bar input{flex:1;min-width:190px}.search-bar select{max-width:100%}input,select{background:white;border:1px solid #cfdbea;border-radius:8px;padding:12px 14px;color:#1d3453;min-height:45px}.callout{background:#eaf3ff;border:1px solid #d6e6fc;border-radius:16px;padding:28px;margin-top:32px;display:flex;justify-content:space-between;align-items:center;gap:24px}.callout h3{margin:0 0 7px}.callout p{margin:0;color:#58708c;font-size:14px}.crumb{display:flex;gap:8px;flex-wrap:wrap;font-size:12px;color:#657b97;margin-bottom:22px}.crumb a{color:#006acb}.empty,.loading{border:1px dashed #cedbec;border-radius:14px;padding:38px;text-align:center;background:white}.empty h3{margin-top:0}.error{color:#a32030;font-size:14px}.empty .error{max-width:550px;margin:0 auto 20px}.loading{color:#58708c}.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:25px}.step{background:white;border:1px solid #e2e9f3;border-radius:15px;padding:26px}.step span{font-weight:800;font-size:30px;color:#007fff}.step h3{font-size:18px}footer{background:#102b50;color:#c5d2e5;padding:40px max(5vw,20px) 25px;display:grid;grid-template-columns:1fr 1fr;gap:25px;font-size:13px}footer strong{color:white;font-size:21px}footer a{display:block;margin:5px 0}footer small{color:#ffd700}footer p{margin:8px 0}.independent{grid-column:1/-1;border-top:1px solid #365070;padding-top:20px;font-size:11px}.quiz{max-width:820px;margin:auto;padding:40px 20px 60px}.quiz-head{display:flex;justify-content:space-between;align-items:center;font-size:13px;color:#5d7390}.progress{height:6px;background:#e2eaf6;border-radius:10px;margin:14px 0 28px}.progress span{display:block;height:100%;background:#007fff;border-radius:10px}.question{background:white;border:1px solid #dee7f3;border-radius:18px;padding:32px}.rich{overflow-wrap:anywhere;overflow-x:auto;line-height:1.8}.rich p{margin:.65em 0}.rich img{max-width:100%;height:auto}.rich table{border-collapse:collapse;max-width:100%}.rich td,.rich th{border:1px solid #d5dfec;padding:8px}.rich iframe{display:none}.question-media{max-height:260px;max-width:100%;display:block;margin:20px auto}.option{display:flex;align-items:center;gap:15px;width:100%;padding:14px 18px;text-align:left;border:1px solid #d8e2ef;border-radius:11px;background:white;color:#203755;margin-top:12px}.option:hover{background:#f4f8ff}.option.selected{border:2px solid #007fff;background:#eaf4ff;padding:13px 17px}.letter{border:1px solid #d5dfec;min-width:30px;height:30px;display:grid;place-items:center;border-radius:8px;font-size:12px}.quiz-controls{display:flex;justify-content:space-between;gap:15px;margin-top:25px}.result{text-align:center;background:white;padding:45px;border:1px solid #dbe6f4;border-radius:18px}.score{font-size:64px;font-weight:800;color:#0074e8;letter-spacing:-3px}.stats{display:flex;justify-content:center;gap:35px;margin:25px 0}.stats strong{display:block;font-size:26px}.stats span{font-size:12px;color:#607693}dialog{border:0;border-radius:20px;padding:35px;width:min(460px,calc(100% - 30px));box-shadow:0 20px 80px #0003;color:#162843}dialog::backdrop{background:#0b2032aa;backdrop-filter:blur(3px)}dialog h2{font-size:26px;line-height:1.2;margin-top:14px}dialog p{font-size:13px;color:#667a93}label{display:block;margin:16px 0;font-size:13px;font-weight:600}label input{display:block;width:100%;margin-top:6px}.close{position:absolute;right:15px;top:10px;font-size:28px;border:0;background:none;color:#607693}.separator{text-align:center;color:#7b8da3;font-size:12px;margin:20px 0}.text-button{display:block;margin:auto}#notice{position:fixed;bottom:20px;left:50%;transform:translateX(-50%);max-width:90vw;background:#173458;color:white;border-radius:12px;padding:13px 22px;box-shadow:0 6px 30px #0002;display:none;font-size:13px;z-index:30}.profile-card{background:white;border:1px solid #e1e9f3;border-radius:16px;padding:30px}.article{max-width:850px}.katex-display{overflow-x:auto;overflow-y:hidden}.course-media{width:100%;min-height:450px;border:0}.course-links{margin:20px 0}.choice-list{display:flex;gap:10px;flex-wrap:wrap;margin:25px 0}
@media(max-width:900px){header{padding:14px 22px;height:auto;flex-wrap:wrap;gap:14px}nav{order:3;width:100%;justify-content:center;gap:26px;border-top:1px solid #edf1f7;padding-top:7px}.hero{gap:35px;padding:45px 25px}.hero h1{font-size:44px}.grid{grid-template-columns:repeat(3,1fr)}.benefits{gap:25px}.study-card{padding:24px}.study-card h3{font-size:21px}}
@media(max-width:640px){.brand{font-size:20px}.brand img{width:45px;height:45px}.brand small{font-size:9px}.button{padding:11px 17px}header>#account{font-size:12px;padding:9px 12px}nav{font-size:12px;gap:22px}.hero{grid-template-columns:1fr;padding:34px 23px 45px;gap:35px}.hero h1{font-size:43px;margin:15px 0;letter-spacing:-1.8px}.hero p{font-size:15px}.study-card{transform:none;max-width:440px;width:100%;margin:auto}.study-card:before{display:none}.benefits{gap:15px;justify-content:space-around;font-size:10px;padding:18px 15px}.benefits span{max-width:95px}.grid{grid-template-columns:repeat(2,1fr);gap:12px}.subject{padding:18px;min-height:180px}.subject h3{font-size:14px}.subject img{width:54px;height:54px}.section{padding:32px 18px 45px}.section-heading{align-items:start;flex-direction:column;gap:10px}h2{font-size:26px}.callout{flex-direction:column;align-items:start;padding:24px}.steps{grid-template-columns:1fr;gap:12px}footer{grid-template-columns:1fr}.question{padding:22px 18px}.stats{gap:20px}.result{padding:30px 18px}.quiz-controls .button{font-size:12px}.course-media{min-height:320px}.search-bar select{width:100%}}

[hidden]{display:none!important}#consent-label input{display:inline-block;width:auto;min-height:auto;margin:0 8px 0 0}#consent-label a{text-decoration:underline;color:#006fdc}

.preview-banner{background:#fff5cc;color:#5c4800;border-bottom:1px solid #ecd98a;padding:12px 5vw;font-size:13px;text-align:center}.preview-banner strong{margin-right:10px}button:disabled{cursor:not-allowed} @media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.subject{transition:none}}

/* Account sign-in and explicit-credit PATSH GPT composer. */
textarea{font:inherit;resize:vertical;background:white;border:1px solid #cfdbea;border-radius:10px;padding:14px;color:#1d3453;line-height:1.6;min-height:150px;max-width:100%}
.chat-page{max-width:1100px}.chat-heading{display:flex;align-items:center;justify-content:space-between;gap:20px}.chat-heading h1{margin:8px 0 12px;font-size:38px;letter-spacing:-1.3px}.chat-balance{border:1px solid #d4e4f6;border-radius:30px;background:#fff;padding:9px 16px;color:#0066ca;font-size:13px;white-space:nowrap}.chat-layout{display:grid;grid-template-columns:minmax(0,1fr) 260px;gap:24px;margin-top:28px;align-items:start}.chat-workspace{background:#fff;border:1px solid #e1e9f3;border-radius:18px;padding:28px;min-width:0}.chat-workspace select,.chat-workspace textarea,.chat-workspace input{width:100%}.chat-workspace label{margin:16px 0 7px}.chat-compose-meta{display:flex;align-items:center;justify-content:space-between;gap:15px;margin-top:12px}.chat-compose-meta .muted{font-size:12px}.chat-aside{padding:24px;background:#eaf3ff;border:1px solid #d6e6fc;border-radius:16px}.chat-aside h2{font-size:20px;letter-spacing:-.5px;line-height:1.3;margin-top:0}.chat-aside p{font-size:13px;color:#526a86}.chat-aside .text-button{padding:8px 0;font-size:13px}.chat-bubble{white-space:pre-wrap;overflow-wrap:anywhere;line-height:1.75;padding:18px;border-radius:12px;margin:0 0 15px;font-size:15px}.chat-question{background:#eaf3ff;margin-left:22px}.chat-answer{background:#f5f8fc;border:1px solid #e1e9f3;margin-right:15px}.request-reference{overflow-wrap:anywhere;color:#657b97;font-size:11px}.field-hint{font-size:12px;color:#657b97;margin:6px 0}#chat-result:not(:empty){border-bottom:1px solid #e1e9f3;padding-bottom:22px;margin-bottom:22px}#auth-error:empty,#chat-error:empty{display:none}#auth button:disabled{cursor:wait}#auth input[type=password]{letter-spacing:normal}
@media(max-width:900px){header nav{gap:22px;flex-wrap:wrap}.chat-layout{grid-template-columns:minmax(0,1fr) 220px;gap:18px}}
@media(max-width:640px){header nav{gap:18px}.chat-heading{align-items:start;flex-direction:column;gap:4px}.chat-heading h1{font-size:33px}.chat-layout{grid-template-columns:1fr;margin-top:20px}.chat-workspace{padding:20px 16px}.chat-compose-meta{align-items:stretch;flex-direction:column}.chat-compose-meta .button{width:100%}.chat-aside{padding:20px}.chat-question{margin-left:10px}.chat-answer{margin-right:5px}dialog{padding:30px 24px}}