:root{--bg:#f5f6f8;--surface:#fff;--surface-2:#eef0f3;--border:#d9dce1;--text:#1c1f24;--text-muted:#6b7280;--accent:#2f6feb;--accent-contrast:#fff;--accent-bg:#2f6feb1a;--error-bg:#fdeceb;--error-border:#e5534b;--error-text:#8a1f16;--success-bg:#e9f7ee;--success-border:#2f9e51;--success-text:#185c30;--warning-bg:#fff6e0;--warning-border:#d19a1f;--warning-text:#6b4e03;--sans:system-ui, "Segoe UI", Roboto, sans-serif;--mono:ui-monospace, Consolas, monospace;--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light}:root[data-theme=dark]{--bg:#14161a;--surface:#1b1e24;--surface-2:#22262e;--border:#2e333c;--text:#e6e8eb;--text-muted:#9aa1ac;--accent:#5b9dff;--accent-contrast:#0b1220;--accent-bg:#5b9dff26;--error-bg:#3a1c1c;--error-border:#e5534b;--error-text:#ffb4ac;--success-bg:#163826;--success-border:#2f9e51;--success-text:#86e0a8;--warning-bg:#3a2f0f;--warning-border:#d19a1f;--warning-text:#f0cd6f;--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark}*{box-sizing:border-box}body{background:var(--bg);color:var(--text);font:15px/1.55 var(--sans);margin:0}.app{max-width:1040px;margin:0 auto;padding:16px 20px 64px}.site-header{align-items:center;gap:10px;margin-bottom:16px;display:flex}.site-header__brand{color:var(--accent);white-space:nowrap;font-size:15px;font-weight:700;text-decoration:none}.site-header__brand:hover{text-decoration:underline}.site-header__divider{color:var(--text-muted);font-weight:400}.site-header__title{color:var(--text-muted);white-space:nowrap;font-size:15px;font-weight:600}.toolbar-spacer{flex:1}.btn,.toggle-btn{border:1px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer;border-radius:6px;padding:6px 12px;font-family:inherit;font-size:13px}.btn:hover,.toggle-btn:hover{border-color:var(--accent)}.btn--primary{background:var(--accent);color:var(--accent-contrast);border-color:var(--accent)}.btn--primary:hover{opacity:.9}.btn:disabled{opacity:.5;cursor:not-allowed}.icon-btn{padding:6px 10px}.nav-tabs{border-bottom:1px solid var(--border);flex-wrap:wrap;gap:4px;margin-bottom:20px;display:flex}.nav-tabs__tab{color:var(--text-muted);cursor:pointer;background:0 0;border:none;border-bottom:2px solid #0000;margin-bottom:-1px;padding:10px 14px;font-family:inherit;font-size:14px;font-weight:600}.nav-tabs__tab:hover{color:var(--text)}.nav-tabs__tab--active{color:var(--accent);border-bottom-color:var(--accent)}.app__main{min-height:60vh}.section-layout{grid-template-columns:240px 1fr;align-items:start;gap:24px;display:grid}@media (width<=720px){.section-layout{grid-template-columns:1fr}}.sidebar{flex-direction:column;gap:2px;display:flex;position:sticky;top:16px}.sidebar__group-title{text-transform:uppercase;letter-spacing:.05em;color:var(--text-muted);margin:14px 0 4px;font-size:11px}.sidebar__group-title:first-child{margin-top:0}.sidebar__item{text-align:left;width:100%;color:var(--text);cursor:pointer;background:0 0;border:none;border-radius:6px;padding:7px 10px;font-family:inherit;font-size:13.5px;display:block}.sidebar__item:hover{background:var(--surface-2)}.sidebar__item--active{background:var(--accent-bg);color:var(--accent);font-weight:600}.sidebar__item-check{color:var(--success-border);margin-right:6px}.card{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:20px}.card+.card{margin-top:16px}.chip-row{flex-wrap:wrap;gap:6px;display:flex}.chip{border:1px solid var(--border);background:var(--surface);color:var(--text-muted);cursor:pointer;border-radius:999px;padding:5px 12px;font-family:inherit;font-size:12.5px}.chip:hover{border-color:var(--accent);color:var(--text)}.chip--active{background:var(--accent);border-color:var(--accent);color:var(--accent-contrast)}.lesson-header h2{margin:0 0 4px}.lesson-summary{color:var(--text-muted);margin:0 0 16px}.lesson-body p{margin:0 0 14px}.lesson-body ul{margin:0 0 14px;padding-left:20px}.lesson-body li{margin-bottom:6px}.callout{border-left:3px solid var(--accent);background:var(--accent-bg);border-radius:6px;margin:0 0 14px;padding:10px 14px;font-size:14px}.callout--warning{border-left-color:var(--warning-border);background:var(--warning-bg);color:var(--warning-text)}.related-terms{flex-wrap:wrap;gap:6px;margin-top:8px;display:flex}.term-link{border:1px solid var(--border);color:var(--accent);background:var(--surface);cursor:pointer;border-radius:999px;padding:3px 10px;font-size:12px;text-decoration:none;display:inline-block}.term-link:hover{border-color:var(--accent)}.mark-read-row{align-items:center;gap:10px;margin:16px 0;display:flex}.read-badge{color:var(--success-text);background:var(--success-bg);border:1px solid var(--success-border);border-radius:999px;padding:4px 10px;font-size:12.5px}.mini-quiz{border-top:1px solid var(--border);margin-top:28px;padding-top:20px}.mini-quiz h3{margin-top:0}.glossary-search{border:1px solid var(--border);background:var(--surface);width:100%;color:var(--text);border-radius:6px;margin-bottom:10px;padding:8px 12px;font-family:inherit;font-size:13.5px}.glossary-entry h2{margin:0 0 4px}.sim-grid{grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:12px;display:grid}.sim-card{text-align:left;border:1px solid var(--border);background:var(--surface);cursor:pointer;border-radius:10px;width:100%;padding:14px 16px;font-family:inherit;display:block}.sim-card:hover{border-color:var(--accent)}.sim-card h3{margin:0 0 6px;font-size:14.5px}.sim-card p{color:var(--text-muted);margin:0;font-size:13px}.sim-back{margin-bottom:14px}.strength-input{border:1px solid var(--border);background:var(--surface);width:100%;color:var(--text);font-family:var(--mono);border-radius:6px;padding:10px 12px;font-size:14px}.strength-bar-track{background:var(--surface-2);border-radius:4px;height:8px;margin:12px 0 8px;overflow:hidden}.strength-bar-fill{border-radius:4px;height:100%;transition:width .2s,background .2s}.strength-meta{color:var(--text-muted);justify-content:space-between;font-size:13px;display:flex}.inbox-mail{border:1px solid var(--border);background:var(--surface);border-radius:8px;padding:14px}.inbox-field{cursor:pointer;border:1px dashed #0000;border-radius:4px;margin:2px -6px;padding:4px 6px}.inbox-field:hover{border-color:var(--border)}.inbox-field--found{border-color:var(--success-border);background:var(--success-bg)}.quiz-progress{color:var(--text-muted);margin-bottom:10px;font-size:13px}.quiz-prompt{margin:0 0 16px;font-size:16px;font-weight:600}.quiz-choices{flex-direction:column;gap:8px;display:flex}.quiz-choice{text-align:left;border:1px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer;border-radius:8px;padding:10px 14px;font-family:inherit;font-size:14px}.quiz-choice:hover:not(:disabled){border-color:var(--accent)}.quiz-choice--correct{border-color:var(--success-border);background:var(--success-bg);color:var(--success-text)}.quiz-choice--incorrect{border-color:var(--error-border);background:var(--error-bg);color:var(--error-text)}.quiz-explanation{background:var(--surface-2);border-radius:8px;margin-top:14px;padding:12px 14px;font-size:13.5px}.flashcard{border:1px solid var(--border);text-align:center;cursor:pointer;border-radius:10px;justify-content:center;align-items:center;min-height:120px;padding:24px;font-size:15px;display:flex}.flashcard--answer{background:var(--accent-bg)}.flashcard-actions{justify-content:center;gap:8px;margin-top:14px;display:flex}.score-summary{text-align:center}.score-summary .score-value{color:var(--accent);font-size:40px;font-weight:700}.missed-list{text-align:left;margin-top:16px}.filters-row{flex-wrap:wrap;gap:10px;margin-bottom:16px;display:flex}.filters-row select{border:1px solid var(--border);background:var(--surface);color:var(--text);border-radius:6px;padding:6px 10px;font-family:inherit;font-size:13px}.mode-toggle{gap:4px;margin-bottom:16px;display:flex}.category-tag{color:var(--text-muted);background:var(--surface-2);border-radius:999px;margin-bottom:10px;padding:2px 9px;font-size:11.5px;display:inline-block}.step-controls{align-items:center;gap:10px;margin-top:16px;display:flex}.step-controls span{color:var(--text-muted);font-size:13px}.handshake-step{border:1px solid var(--border);background:var(--surface);border-radius:8px;margin-bottom:10px;padding:14px}.handshake-step--active{border-color:var(--accent);background:var(--accent-bg)}.packet{font-family:var(--mono);background:var(--surface-2);word-break:break-all;border-radius:6px;padding:8px 10px;font-size:12.5px}.packet--plain{border:1px solid var(--error-border);color:var(--error-text);background:var(--error-bg)}.packet--encrypted{border:1px solid var(--success-border);color:var(--success-text);background:var(--success-bg)}.decision-node{border:1px solid var(--border);background:var(--surface);border-radius:8px;padding:16px}.decision-node h3{margin:0 0 10px}.decision-options{flex-direction:column;gap:8px;margin-top:12px;display:flex}