@font-face{font-family:'Space Grotesk';src:url('assets/fonts/space-grotesk-latin-400-normal.woff2') format('woff2');font-weight:400;font-display:swap}
@font-face{font-family:'Space Grotesk';src:url('assets/fonts/space-grotesk-latin-500-normal.woff2') format('woff2');font-weight:500;font-display:swap}
@font-face{font-family:'Space Grotesk';src:url('assets/fonts/space-grotesk-latin-700-normal.woff2') format('woff2');font-weight:700;font-display:swap}
:root{color-scheme:light;--vm-navy:#0F2557;--vm-blue:#2F6FDE;--vm-sky:#5CA2FF;--vm-deep:#1A3A82;--vm-mist:#E8F0FE;--vm-white:#fff;--ink:var(--vm-navy);--blue:var(--vm-blue);--muted:var(--vm-deep);--line:rgba(15,37,87,.17)}
*{box-sizing:border-box}
body{margin:0;background:var(--vm-mist);color:var(--ink);font:400 16px/1.65 'Space Grotesk',system-ui,sans-serif}
header{background:var(--vm-white);border-bottom:1px solid var(--line)}
.header-inner{max-width:1080px;margin:auto;padding:0 24px;display:flex;align-items:center;gap:0;min-height:102px}
.brand{display:flex;align-items:center;padding:21px;flex-shrink:0}
.brand img{display:block;width:175px;height:auto;max-width:100%}
.app-identity{border-left:1px solid var(--line);padding-left:25px;display:flex;flex-direction:column;gap:2px}
.app-identity strong{font-size:18px;font-weight:700;letter-spacing:-.02em}
.app-identity small{font-size:12px;color:var(--muted)}
.header-note{margin-left:auto;padding-left:20px;font-size:12px;color:var(--muted)}
main{max-width:960px;margin:48px auto;padding:0 24px}
.eyebrow{text-transform:uppercase;letter-spacing:.12em;font-size:12px;color:var(--vm-deep);font-weight:700}
h1{font-size:clamp(30px,5vw,44px);line-height:1.16;letter-spacing:-.035em;font-weight:700;max-width:800px;text-wrap:balance;margin:14px 0}
h2{font-size:23px;line-height:1.4;letter-spacing:-.02em;margin:8px 0 24px;font-weight:700}
h2:focus{outline:none}
h3{font-weight:700;letter-spacing:-.02em}
p{margin:8px 0 24px;color:var(--muted)}
#quiz-intro{max-width:720px;margin-bottom:30px}
.panel{background:var(--vm-white);border:1px solid var(--line);border-radius:18px;padding:30px;box-shadow:0 8px 28px rgba(15,37,87,.04)}
.library{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(240px,100%),1fr));gap:16px}
button{font:inherit;cursor:pointer;border:1px solid var(--line);border-radius:10px;background:var(--vm-white);color:var(--ink);padding:14px 18px;min-height:48px}
button:hover:not(:disabled){border-color:var(--vm-blue)}
button:focus-visible,input:focus-visible,summary:focus-visible,a:focus-visible{outline:3px solid var(--vm-blue);outline-offset:4px}
.quiz-tile{text-align:left;display:flex;flex-direction:column;gap:12px;align-items:flex-start;padding:22px;min-height:192px;border-top:3px solid var(--vm-blue)}
.quiz-tile:hover{background:var(--vm-mist)}
.quiz-tile strong{font-size:20px;font-weight:700;letter-spacing:-.025em}
.quiz-tile span{color:var(--muted);font-size:14px;line-height:1.6}
.quiz-tile .tile-action{color:var(--vm-deep);font-weight:500;margin-top:auto;padding-top:12px}
.meta{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-bottom:12px;font-size:14px;color:var(--muted)}
progress{width:100%;height:7px;accent-color:var(--vm-blue);display:block;margin-bottom:24px}
.options{display:grid;gap:12px}
.option{display:flex;text-align:left;align-items:center;gap:14px;width:100%;overflow-wrap:anywhere}
.option:not(:disabled):hover{background:var(--vm-mist);border-color:var(--vm-blue)}
.letter{font-size:13px;border-radius:6px;background:var(--vm-mist);padding:3px 9px;font-weight:700;flex-shrink:0;overflow-wrap:normal}
.option:disabled{cursor:default;color:var(--ink);opacity:1}
.correct{background:#eaf7ef;border-color:#399966}
.wrong{background:#fff0ee;border-color:#d17365}
.feedback{margin-top:20px;padding:18px;border-radius:10px;background:var(--vm-mist)}
.feedback p{margin:5px 0 0;color:var(--ink)}
.actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:24px}
.primary{background:var(--vm-blue);color:var(--vm-white);border-color:var(--vm-blue);font-weight:500}
.primary:hover:not(:disabled){background:var(--vm-deep);border-color:var(--vm-deep)}
.score{font-size:58px;font-weight:700;letter-spacing:-.04em;line-height:1.2;margin:20px 0}
.review{border-top:1px solid var(--line);padding:18px 0}
.review p{margin:8px 0;color:var(--ink)}
.source-settings{margin-top:28px;padding-top:20px;border-top:1px solid var(--line)}
summary{cursor:pointer;color:var(--vm-navy);font-weight:500;min-height:36px}
.source-settings p{margin:12px 0}
.source-settings label{display:block;margin:10px 0 6px}
.source-settings input{width:100%;padding:12px;border:1px solid var(--line);border-radius:10px;font:inherit;color:var(--ink);background:var(--vm-white)}
.source-settings .actions{margin-top:12px}
.json-guide h3{font-size:17px;margin:24px 0 8px}
.json-guide pre{padding:18px;background:var(--vm-white);border:1px solid var(--line);border-radius:10px;font-size:13px;line-height:1.65;white-space:pre-wrap;overflow-wrap:anywhere}
.json-guide li{margin:10px 0}
a{color:var(--vm-deep)}
.json-guide ul{padding-left:22px}
.question-code{margin:0 0 22px;min-width:0}
.question-code figcaption{font-size:12px;font-weight:500;color:var(--muted);margin-bottom:6px}
.question-code pre{margin:0;padding:18px;background:var(--vm-navy);color:var(--vm-white);border-radius:10px;white-space:pre-wrap;overflow-wrap:anywhere;tab-size:2;font-size:14px;line-height:1.65}
code{font-family:ui-monospace,SFMono-Regular,Consolas,monospace}
footer{font-size:12px;color:var(--muted);margin:30px 0;display:flex;flex-wrap:wrap;gap:12px;justify-content:space-between}
.hidden{display:none}
@media(max-width:640px){.header-inner{padding:0 4px;min-height:86px}.brand{padding:18px}.brand img{width:145px}.app-identity{padding-left:18px}.app-identity strong{font-size:16px}.app-identity small,.header-note{display:none}main{margin:30px auto;padding:0 16px}.panel{padding:20px}.quiz-tile{padding:20px;min-height:170px}h1{font-size:32px}h2{font-size:21px}.question-code pre{font-size:13px}}
@media(prefers-reduced-motion:no-preference){button{transition:background-color .15s,border-color .15s}}
.account-controls{margin-left:auto;display:flex;align-items:center;gap:12px;padding-left:18px}.account-controls button{font-size:13px;min-height:40px;padding:8px 13px}.learner-name{font-size:13px;max-width:150px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.daily-review{margin-bottom:24px;border-top:3px solid var(--vm-blue)}.daily-review h2{margin-bottom:10px}.daily-review p{margin:8px 0 14px}.daily-review .actions{margin-top:12px}.small-note{font-size:13px}.recall-controls{margin-top:22px;padding-top:18px;border-top:1px solid var(--line)}.recall-controls p{margin:8px 0 12px}.rating-buttons{display:flex;flex-wrap:wrap;gap:10px}.rating-buttons button{min-width:85px}.review-error{color:#8e2525}button:disabled{cursor:default;opacity:.55}.option:disabled{opacity:1}dialog{width:min(480px,calc(100% - 32px));max-height:calc(100dvh - 40px);overflow:auto;border:1px solid var(--line);border-radius:18px;padding:26px;background:var(--vm-white);color:var(--vm-navy);font:inherit;box-shadow:0 24px 100px #0f255733}dialog::backdrop{background:#0f255788}.dialog-top{display:flex;align-items:flex-start;justify-content:space-between;gap:12px}.dialog-top h2{margin:0 0 15px}.dialog-top button{padding:6px 10px;min-height:36px;font-size:12px}dialog form{display:grid;gap:15px}dialog label{display:grid;gap:6px;font-size:14px;font-weight:500}dialog input{font:inherit;font-size:16px;width:100%;padding:12px;border:1px solid var(--line);border-radius:9px;color:var(--vm-navy);background:white}dialog .auth-message{font-size:13px;margin:0}dialog .actions{gap:8px}dialog .actions button{font-size:13px;padding:8px 12px;min-height:40px}@media(max-width:640px){.app-identity{border:0;padding-left:0}.app-identity small,.learner-name{display:none}.account-controls{padding-left:8px;gap:6px}.account-controls button{padding:8px}.brand img{width:125px}.brand{padding:16px}.app-identity strong{font-size:14px}.header-inner{padding:0 2px}.rating-buttons button{flex:1;min-width:70px}dialog{padding:20px}}
.topic-filter{display:flex;align-items:center;flex-wrap:wrap;gap:12px;font-size:14px;margin:14px 0}.topic-filter select{font:inherit;background:var(--vm-white);color:var(--vm-navy);border:1px solid var(--line);border-radius:8px;padding:8px 12px;max-width:100%;min-height:42px}.topic-filter select:focus-visible{outline:3px solid var(--vm-blue);outline-offset:3px}
.social-login { display: grid; gap: 10px; margin: 16px 0; }
.social-login:empty { display: none; }
.social-login button { width: 100%; }
.auth-divider { text-align: center; color: var(--muted, #52627e); font-size: .9rem; }

.shortcut-key{display:inline-block;margin-left:10px;padding:1px 6px;border:1px solid currentColor;border-radius:5px;font:500 12px/1.6 'Space Grotesk',system-ui,sans-serif;white-space:nowrap;opacity:.85}.shortcut-guide{margin:16px 0 0;font-size:12px;line-height:1.8;color:var(--muted)}kbd.letter{font-family:inherit}

.answer-example:empty{display:none}.answer-example{margin-top:22px;padding-top:20px;border-top:1px solid var(--line)}.answer-example h3{font-size:18px;margin:6px 0 14px}.answer-example .question-code{margin-bottom:14px}.answer-example pre{max-height:360px;overflow:auto}.answer-example p{font-size:14px;margin:10px 0 14px}.example-links{display:flex;flex-wrap:wrap;gap:18px;font-size:13px}
/* Practice controls: native ranges retain keyboard and touch behavior. */
.practice-setup{max-width:760px;margin:auto}.practice-setup h2{margin-bottom:8px}.setup-intro{max-width:540px}.practice-sliders{display:flex;justify-content:center;gap:90px;padding:12px 20px 24px}.practice-slider{display:grid;grid-template-rows:auto auto 220px auto;justify-items:center;gap:12px;min-width:150px}.practice-slider label{font-size:14px;font-weight:500}.practice-slider output{font-size:26px;font-weight:700;letter-spacing:-.04em;min-height:44px}.practice-slider input[type=range]{writing-mode:vertical-lr;direction:rtl;width:54px;height:220px;cursor:pointer;background:transparent;appearance:none;-webkit-appearance:none;--control-color:var(--vm-blue)}.practice-slider.focus-slider input{--control-color:#168e8c}.practice-slider input::-webkit-slider-runnable-track{width:12px;height:100%;border-radius:20px;background:var(--line)}.practice-slider input::-webkit-slider-thumb{appearance:none;-webkit-appearance:none;width:34px;height:34px;margin-left:-11px;border:5px solid var(--vm-white);border-radius:50%;background:var(--control-color);box-shadow:0 0 0 2px var(--control-color)}.practice-slider input::-moz-range-track{width:12px;height:100%;border-radius:20px;background:var(--line)}.practice-slider input::-moz-range-thumb{width:24px;height:24px;border:5px solid var(--vm-white);border-radius:50%;background:var(--control-color);box-shadow:0 0 0 2px var(--control-color)}.practice-slider input:focus-visible{outline:3px solid var(--vm-blue);outline-offset:5px;border-radius:12px}.practice-slider input:disabled{opacity:.45;cursor:default}.slider-ends{display:flex;justify-content:space-between;gap:16px;font-size:11px;color:var(--muted);width:100%}.setup-summary{text-align:center;margin:6px 0 22px;font-size:14px;min-height:24px}.setup-actions{display:flex;gap:12px;align-items:center;flex-wrap:wrap;border-top:1px solid var(--line);padding-top:20px}.setup-actions .primary{margin-left:auto}.practice-setup>.small-note{margin:16px 0 0;font-size:12px}.setup-back{display:block;margin:20px auto}.reset-preferences{font-size:14px}.account-controls [data-theme-control]{white-space:nowrap}
:root[data-theme=dark]{color-scheme:dark;--vm-navy:#e4edff;--vm-deep:#b6c8ed;--vm-blue:#83b2ff;--vm-mist:#0b1423;--vm-white:#15243c;--ink:#e4edff;--muted:#b6c8ed;--line:rgba(198,217,255,.22)}
:root[data-theme=dark] .brand img{background:#fff;border-radius:8px;padding:5px}:root[data-theme=dark] .question-code pre{background:#09111f;color:#e6efff}:root[data-theme=dark] .primary{color:#0b1423}:root[data-theme=dark] .correct{background:#133c30;border-color:#51bd8d}:root[data-theme=dark] .wrong{background:#482a30;border-color:#db8794}:root[data-theme=dark] .review-error{color:#ffb3bc}:root[data-theme=dark] dialog input{background:var(--vm-mist);color:var(--ink)}:root[data-theme=dark] .practice-slider.focus-slider input{--control-color:#50cfc0}
@media(max-width:640px){.practice-sliders{display:grid;gap:32px;padding:10px 4px 28px}.practice-slider{width:100%;min-width:0;grid-template-rows:auto auto 44px auto;gap:6px}.practice-slider input[type=range]{writing-mode:horizontal-tb;direction:ltr;width:100%;height:44px}.practice-slider input::-webkit-slider-runnable-track{height:10px;width:100%}.practice-slider input::-webkit-slider-thumb{margin-left:0;margin-top:-12px}.practice-slider input::-moz-range-track{height:10px;width:100%}.practice-slider output{font-size:24px;min-height:36px}.setup-actions{gap:8px}.setup-actions button{padding:10px 12px;font-size:13px}.setup-actions .primary{width:100%;margin:6px 0 0}.account-controls [data-theme-control]{max-width:104px;font-size:11px;padding:6px}.header-inner .brand img{width:100px}.app-identity strong{font-size:12px}}
@media(max-width:640px){.header-inner .app-identity{display:none}}
@media(max-width:640px){.practice-sliders{justify-content:stretch}}
@media(min-width:641px){.practice-setup{max-width:620px;padding:24px}.setup-intro{font-size:14px;margin-bottom:18px}.practice-sliders{gap:22px;padding:4px 8px 16px}.practice-slider{width:130px;min-width:0;grid-template-rows:auto auto 140px auto;gap:8px}.practice-slider output{font-size:22px;min-height:34px}.practice-slider input[type=range]{width:44px;height:140px}.setup-summary{margin:2px 0 16px;font-size:13px}.setup-actions{padding-top:16px}.setup-actions button{padding:10px 14px;font-size:14px}}
.sr-only{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.practice-slider{position:relative;grid-template-rows:auto 220px auto}.slider-help{position:absolute;z-index:5;bottom:calc(100% + 10px);left:50%;transform:translateX(-50%);display:grid;gap:5px;width:230px;padding:12px 14px;background:var(--vm-navy);color:var(--vm-white);border-radius:10px;box-shadow:0 8px 26px #07172e26;font-size:12px;line-height:1.55;opacity:0;visibility:hidden;pointer-events:none;text-align:left}.slider-help strong{font-size:13px}.practice-slider:hover .slider-help,.practice-slider:focus-within .slider-help{opacity:1;visibility:visible}:root[data-theme=dark] .slider-help{background:#dce9ff;color:#0b1423}
@media(min-width:641px){.practice-slider{grid-template-rows:auto 140px auto}}
@media(max-width:640px){.practice-slider{grid-template-rows:auto 44px auto}}