.brain-page [hidden]{display:none!important}.brain-hero{padding:3rem 0 2rem;max-width:760px}.brain-hero h1{font:650 clamp(2.5rem,6vw,4.7rem)/1.12 Inter,system-ui,sans-serif;letter-spacing:-.04em;text-transform:none}.brain-hero h1 em{color:var(--gold);text-shadow:0 0 12px #f6c64322}.brain-hero>p{line-height:1.7;color:#c0d0d4}.brain-tags{display:flex;gap:.6rem;flex-wrap:wrap}.brain-tags span{border:1px solid #70e6dc44;border-radius:99px;padding:.35rem .8rem;color:var(--cyan)}.brain-panel{max-width:840px;border:1px solid #70e6dc66;border-radius:22px;padding:clamp(1.1rem,4vw,2.4rem);background:linear-gradient(140deg,#132535,#101b28);box-shadow:0 0 32px #70e6dc0b}.brain-page h2,.brain-page h3{font-family:Inter,system-ui,sans-serif;text-transform:none;font-weight:600;letter-spacing:-.02em}.brain-panel p{line-height:1.7;color:#c3d2db}.brain-panel label{display:block;margin:1rem 0 .5rem;color:#dce4e7}.brain-page :is(select,input){width:100%;max-width:580px;min-height:52px;padding:.8rem;border:1px solid #708a98;border-radius:9px;background:#091622;color:#e0e9ed;font:inherit}.brain-page button{min-height:50px;max-width:100%;padding:.7rem 1.2rem;border:1px solid #70e6dc88;border-radius:10px;background:#173b40;color:#d8f8f1;font:600 1rem/1.5 Inter,system-ui,sans-serif;letter-spacing:0;text-transform:none;cursor:pointer;white-space:normal}.brain-page button:hover{background:#205157}.brain-page button.quiet{background:#142333;color:#cedbe1;border-color:#607c8c}.brain-page :is(button,select,input,a):focus-visible{outline:3px solid var(--gold);outline-offset:4px}.brain-session-head{display:flex;gap:1rem;justify-content:space-between;align-items:center;flex-wrap:wrap}.brain-prompt{font:600 clamp(2rem,8vw,4rem)/1.4 ui-monospace,monospace;color:#f6d784!important;margin:1.5rem 0;overflow-wrap:anywhere}.brain-prompt.digits{letter-spacing:.13em}.brain-binary{display:grid;grid-template-columns:1fr 1fr;gap:1rem;max-width:500px}#number-form button{display:block;margin-top:1rem}#feedback:empty{display:none}#feedback{border-left:3px solid var(--gold);padding:1rem;background:#1b2a30}#best{font-size:.9rem}.brain-notes{display:grid;grid-template-columns:1fr 1fr;gap:2rem;margin:2.5rem 0;max-width:900px}.brain-notes p{color:#afc3ce;line-height:1.7}.brain-notes a{color:var(--cyan)}@media(max-width:640px){.brain-notes{grid-template-columns:1fr}.brain-prompt.digits{letter-spacing:.06em;font-size:clamp(1.5rem,7vw,2.5rem)}}@media(forced-colors:active){.brain-panel,.brain-tags span,.brain-page :is(button,select,input),#feedback{border:1px solid CanvasText;background:Canvas;color:CanvasText!important}.brain-hero h1 em{color:CanvasText;text-shadow:none}}