:root{--blue:#1257d5;--navy:#122c50;--ink:#193553;--muted:#62738b;--line:#dbe5f2;--pale:#edf5ff;--bg:#f8faff;--radius:22px;font-family:Tahoma,"Noto Sans Thai",system-ui,sans-serif;color:var(--ink);background:var(--bg);font-size:16px;line-height:1.75;font-synthesis:none}*{box-sizing:border-box}body{margin:0}a{color:var(--blue);text-decoration:none}button,input,select,textarea{font:inherit}button,a,input,select,textarea{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button:disabled{opacity:.6;cursor:wait}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:3px solid #327ce8;outline-offset:4px}h1,h2,h3,p{margin-top:0}h1,h2,h3{color:var(--navy);line-height:1.45}h1{font-size:clamp(36px,4.6vw,62px);letter-spacing:-1.5px;margin-bottom:24px}h2{font-size:clamp(23px,2.8vw,30px);margin-bottom:12px}h3{font-size:20px;margin-bottom:12px}p{margin-bottom:16px}small{font-size:12px}strong{font-weight:700}button{border:0}img{max-width:100%}[hidden]{display:none!important}.container{max-width:1180px;padding:0 30px;margin:auto;min-height:65vh}.site-header{background:#fff;border-bottom:1px solid var(--line)}.nav-wrap{max-width:1240px;padding:20px 30px;margin:auto;display:flex;align-items:center;justify-content:space-between;gap:20px}.brand{display:flex;align-items:center;gap:12px;color:var(--navy);font-size:22px;font-weight:800;line-height:1.3}.brand 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p{font-size:14px}.sample-option{padding:10px 15px;border:1px solid var(--line);border-radius:10px;margin-bottom:10px;font-size:14px}.sample-option.chosen{background:#f0f7ff;border-color:#76a8ef;color:var(--blue)}.sample-option small{float:right}.sample-option span{margin-right:10px}.sample-progress{height:5px;background:#edf2fa;border-radius:10px;margin-top:20px}.sample-progress i{display:block;width:25%;height:100%;background:var(--blue);border-radius:10px}.sample-bottom{font-size:10px;display:flex;justify-content:space-between;margin-top:12px}.sample-bottom b{color:var(--blue)}.visual-caption{text-align:center;font-size:11px;margin-top:25px;color:#4b6a91}.section-head{display:flex;justify-content:space-between;align-items:end;gap:20px;margin-bottom:25px}.section-head .eyebrow{margin-bottom:10px}.section-head p{font-size:14px;color:var(--muted)}.learning-path{display:grid;grid-template-columns:repeat(6,1fr);border:1px solid 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.button:first-child{flex:1}.feedback{padding:18px;border-radius:14px;background:var(--pale);margin-top:18px;overflow-wrap:anywhere}.feedback.success{background:#effaf5;border:1px solid #a2d5b9;color:#205d3e}.feedback.error{background:#fff3f3;color:#962e3c}.progress-track{height:7px;background:#e3edfb;border-radius:20px;overflow:hidden}.progress-track div{height:100%;background:var(--blue);transition:width .25s}.quest-side{position:sticky;top:20px}.quest-side h3{font-size:17px}.quest-side .stat{border:0;padding:8px 0}.step-tags{display:flex;flex-wrap:wrap;gap:7px;margin:16px 0}.step-tags span{font-size:11px;padding:4px 9px;border-radius:8px;background:#f3f6fb;color:var(--muted)}.step-tags .active{background:var(--blue);color:white}.result-title{text-align:center;padding:20px}.result-title strong{font-size:58px;color:var(--blue);display:block}.summary-item{padding:16px 0;border-top:1px solid var(--line);font-size:14px}.summary-item 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0;font-size:14px}.hint-list{font-size:14px;color:#2b5485;padding-left:20px}.logout-button{background:transparent;color:var(--muted);min-height:44px}.badge-row{display:flex;gap:8px;flex-wrap:wrap}.badge-row span{background:var(--pale);color:var(--blue);border-radius:10px;padding:8px 12px;font-size:12px}
@media(max-width:900px){.hero{gap:25px;padding:45px 0}.learning-path{grid-template-columns:repeat(3,1fr)}.learning-path div:nth-child(3){border-right:0}.learning-path div:nth-child(-n+3){border-bottom:1px solid var(--line)}.quest-layout{grid-template-columns:1fr}.quest-side{position:static}.quest-side .stats{margin:0}.grid{gap:14px}.sample-card{padding:18px}.stats{grid-template-columns:repeat(2,1fr)}}
@media(max-width:600px){body{padding-bottom:calc(70px + env(safe-area-inset-bottom))}.container{padding:0 18px}.nav-wrap{padding:14px 18px;gap:12px}.brand{font-size:19px;gap:9px}.brand-icon{width:41px;height:41px;border-radius:12px;font-size:18px}.site-header nav{gap:0}.site-header nav>a{display:none}.hero{grid-template-columns:1fr;gap:30px;padding:35px 0 42px}.hero h1{font-size:43px;line-height:1.35}.eyebrow{font-size:10px;letter-spacing:.5px;margin-bottom:16px}.lead{font-size:16px}.actions{gap:14px}.hero-visual{padding:55px 24px 22px;border-radius:25px}.sample-card{transform:rotate(1deg);padding:22px}.sample-equation{font-size:38px}.section-head{display:block}.section-head h2{font-size:25px}.section-head p{margin:12px 0}.learning-path div{padding:17px 12px}.learning-path strong{font-size:13px}.learning-path small{font-size:10px}.learning-path span{margin-bottom:8px}.grid{grid-template-columns:1fr}.benefits{gap:22px;margin:30px 0}.benefits article{padding:0}.feature-icon{margin-bottom:12px}.benefits h3{font-size:19px}.benefits p{margin-bottom:0}.cta-band{padding:28px 24px;display:block;margin-bottom:35px}.cta-band .button{margin-top:24px;width:100%}.cta-band h2{font-size:24px}.site-footer{padding:25px 18px;display:block}.site-footer>span{display:block;margin-bottom:8px}.mobile-nav{position:fixed;bottom:0;left:0;right:0;display:flex;justify-content:space-around;background:#ffffffed;backdrop-filter:blur(10px);border-top:1px solid var(--line);padding:8px 10px calc(8px + env(safe-area-inset-bottom));z-index:20}.mobile-nav a{display:flex;flex-direction:column;align-items:center;justify-content:center;min-width:70px;min-height:45px;font-size:19px;line-height:1.35;color:#4a668b}.mobile-nav span{font-size:10px;margin-top:4px}.toast{bottom:calc(85px + env(safe-area-inset-bottom));width:max-content}.membership-grid{grid-template-columns:1fr;gap:20px;margin-bottom:30px}.plan-card{position:static}.page-heading{padding-top:30px}.page-heading h1{font-size:34px}article{padding:22px}.price{font-size:43px}.payment-row strong{font-size:20px}.stats{gap:10px;margin:20px 0}.stat{padding:15px}.stat strong{font-size:23px}.dashboard-heading{padding-top:25px;gap:8px}.dashboard-heading h1{font-size:27px}.problem-grid{grid-template-columns:1fr;gap:16px}.quest-top{padding:18px 0;font-size:12px}.quest-card{padding:20px}.quest-title{font-size:21px}.equation-box{font-size:17px;padding:14px}.quest-actions{gap:8px}.quest-actions .button{font-size:14px;padding:12px}.quest-actions .button:first-child{flex-basis:100%}.quest-actions .button:not(:first-child){flex:1}.admin-user{display:block}.admin-user .actions{margin-top:14px}.admin-user .actions .button{flex:1;font-size:12px;padding:10px}.search-form{gap:8px}.quest-side{padding:20px}.sample-bottom{font-size:9px}.sample-top{font-size:11px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
#problem-dialog{width:min(820px,calc(100% - 24px));max-height:92dvh;overflow:auto;text-align:left;padding:30px}.editor-step{border:1px solid var(--line);border-radius:14px;padding:18px;margin:18px 0}.editor-step summary{cursor:pointer;font-weight:700;color:var(--blue);min-height:44px;display:list-item;align-content:center}.editor-grid{display:grid;grid-template-columns:1fr 1fr;gap:15px}.editor-step input[type=number]{width:100%;padding:12px;border:1px solid #b8cce7;border-radius:10px;font:inherit;min-height:48px}.editor-step .button{width:auto}#problem-dialog>.dialog-close{width:44px}.editor-step summary::marker{color:var(--blue)}@media(max-width:600px){#problem-dialog{padding:24px 16px}.editor-grid{grid-template-columns:1fr;gap:0}.editor-step{padding:14px}}