/* Logged-in student navigation: four actions, two columns on mobile. */
#study999-student-nav[hidden] {display:none!important}
#study999-student-nav {display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:9px;width:100%;max-width:760px;align-items:stretch}
#study999-student-nav .study999-student-nav-btn {box-sizing:border-box;display:flex;gap:7px;justify-content:center;align-items:center;min-width:0;min-height:43px;padding:9px 12px;border:1px solid transparent;border-radius:11px;font:600 14px/1.25 system-ui,'Microsoft YaHei',sans-serif;white-space:nowrap;cursor:pointer;transition:background-color .15s,border-color .15s,box-shadow .15s}
#study999-student-nav svg {flex:none}
#study999-student-nav .nav-courses {color:#0f766e;background:#f0fdfa;border-color:#99f6e4}
#study999-student-nav .nav-scores {color:#1d4ed8;background:#eff6ff;border-color:#bfdbfe}
#study999-student-nav .nav-settings {color:#6d28d9;background:#f5f3ff;border-color:#ddd6fe}
#study999-student-nav .nav-logout {color:#b91c1c;background:#fff7f7;border-color:#fecaca}
#study999-student-nav .study999-student-nav-btn.is-active:not(.nav-logout) {color:#fff;background:#2563eb;border-color:#2563eb;box-shadow:0 2px 6px #2563eb29}
#study999-student-nav .study999-student-nav-btn:hover {filter:brightness(.96)}
#study999-student-nav .study999-student-nav-btn:focus-visible {outline:3px solid #93c5fd;outline-offset:2px}
body.study999-logged-nav #home,body.study999-logged-nav #account,body.study999-logged-nav #logout,body.study999-logged-nav #portal-links {display:none!important}
#portal-link-feedback {display:none!important}
@media(max-width:720px){#study999-student-nav{grid-template-columns:repeat(2,minmax(0,1fr));width:100%;gap:8px}#study999-student-nav .study999-student-nav-btn{min-height:45px;padding:9px 7px;font-size:14px}}
@media(prefers-reduced-motion:reduce){#study999-student-nav .study999-student-nav-btn{transition:none}}