:root{
 --bg:#f3f6fb; --panel:#ffffff; --text:#1d2939; --muted:#667085; --line:#d8e1ec;
 --accent:#173f72; --accent2:#3169ad; --accent3:#edf4ff; --success:#0b7a54; --shadow:0 8px 24px rgba(16,38,63,.08);
}
*{box-sizing:border-box}
html,body{margin:0;height:100%;font-family:Inter,Segoe UI,Arial,Helvetica,sans-serif;color:var(--text);background:linear-gradient(180deg,#f6f9fd 0%,#eef4fb 100%)}
body{display:flex;overflow:hidden}
a{color:var(--accent2)}
.sidebar{width:340px;background:linear-gradient(180deg,#0e2743 0%,#14365d 100%);color:#eef4fb;display:flex;flex-direction:column;box-shadow:var(--shadow)}
.brand{padding:18px;border-bottom:1px solid rgba(255,255,255,.12)}
.brand-top{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:10px}
.pill{display:inline-flex;align-items:center;padding:5px 10px;border-radius:999px;background:#e8f0ff;color:#153b6a;font-size:12px;font-weight:700}
.pill.ghost{background:rgba(255,255,255,.12);color:#eef4fb}
.brand h1{margin:0;font-size:22px;line-height:1.2}
.brand p{margin:8px 0 0;color:#cfe0f3;font-size:13px;line-height:1.55}
.progress-wrap{padding:14px 18px;border-bottom:1px solid rgba(255,255,255,.12)}
.progress-meta{display:flex;justify-content:space-between;font-size:12px;color:#dce8f5;margin-bottom:8px}
.progress{height:10px;background:rgba(255,255,255,.18);border-radius:999px;overflow:hidden}
.progress-bar{height:100%;width:0;background:linear-gradient(90deg,#77aef6,#cbe0ff)}
.micro-stats{font-size:12px;color:#cfe0f3;margin-top:8px;line-height:1.5}
.search{padding:14px 18px 10px;border-bottom:1px solid rgba(255,255,255,.12)}
.search input{width:100%;padding:11px 13px;border-radius:12px;border:none;outline:none}
.quick-actions{display:grid;grid-template-columns:1fr 1fr 1fr;gap:8px;padding:10px 18px 12px;border-bottom:1px solid rgba(255,255,255,.12)}
.sidebtn{padding:9px 10px;border-radius:10px;border:1px solid rgba(255,255,255,.16);background:rgba(255,255,255,.08);color:#fff;cursor:pointer;font-weight:600}
.nav{overflow:auto;padding:10px 10px 22px}
.nav-group{margin:8px 0}
.nav-group h3{margin:12px 10px 8px;font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:#bcd1ea}
.nav button{display:flex;justify-content:space-between;align-items:center;width:100%;text-align:left;border:none;background:transparent;color:#eef4fb;padding:10px 12px;border-radius:12px;cursor:pointer;font-size:14px;gap:8px}
.nav button .tag{font-size:11px;color:#cfe0f3;background:rgba(255,255,255,.08);padding:3px 7px;border-radius:999px}
.nav button.active,.nav button:hover{background:rgba(255,255,255,.12)}
.nav button.done::after{content:'✓';font-weight:700;color:#d5fbe7}
.main{flex:1;display:flex;flex-direction:column;min-width:0}
.topbar{min-height:64px;background:rgba(255,255,255,.82);backdrop-filter:blur(10px);border-bottom:1px solid var(--line);display:flex;align-items:center;gap:10px;padding:10px 16px;position:sticky;top:0;z-index:10}
.topbar button{padding:10px 13px;border-radius:12px;border:1px solid var(--line);background:#fff;cursor:pointer;font-weight:600}
.title-wrap{flex:1;min-width:0}
.title{font-weight:800;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.subtitleline{font-size:12px;color:var(--muted);margin-top:2px}
#markBtn{background:#f3f8ff;border-color:#cfe0f7;color:#17457b}
#pageWrap{flex:1;overflow:auto;padding:22px;position:relative}
.page{max-width:1160px;margin:0 auto}
.dashboard{display:grid;grid-template-columns:1.3fr .9fr;gap:18px;margin-bottom:18px}
.hero-card,.card,.meta-card,.info-strip{background:var(--panel);border:1px solid var(--line);border-radius:22px;padding:22px;box-shadow:var(--shadow)}
.hero-card{background:linear-gradient(145deg,#ffffff 0%,#f5f9ff 100%)}
.info-strip{padding:14px 18px;display:flex;gap:12px;align-items:center;justify-content:space-between;flex-wrap:wrap;margin-bottom:16px}
.eyebrow{color:var(--accent2);font-size:12px;text-transform:uppercase;letter-spacing:.08em;font-weight:700}
.h1,h1{margin:0 0 10px;font-size:32px;line-height:1.15;color:var(--accent)}
h2{margin:0 0 12px;font-size:20px;color:var(--accent)}
h3{margin:14px 0 8px}
p,li{line-height:1.72}
ul,ol{padding-left:20px}
.hero-actions,.actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:12px}
.primary,.secondary,.reveal-btn,.quiz-box button,.actions button{padding:10px 12px;border-radius:12px;border:1px solid var(--line);background:#fff;cursor:pointer;font-weight:600}
.primary{background:#173f72;color:#fff;border-color:#173f72}
.secondary{background:#f5f9ff;color:#173f72;border-color:#cfe0f7}
.meta-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
.stat{padding:14px;border:1px solid var(--line);border-radius:16px;background:#fbfdff}
.stat .label{font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.06em}
.stat .value{font-size:22px;font-weight:800;margin-top:4px;color:var(--accent)}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin:18px 0}
.tbl{width:100%;border-collapse:collapse}
.tbl th,.tbl td{border:1px solid var(--line);padding:10px 12px;vertical-align:top}
.tbl th{background:#eff5fb;text-align:left}
.flashcard{border:1px solid var(--line);padding:12px;border-radius:16px;margin-bottom:12px;background:#fbfdff}
.flashcard .q{font-weight:700;margin-bottom:8px}
.answer{margin-top:10px;color:#0d4c84;font-weight:700}
.notes{width:100%;min-height:140px;border:1px solid var(--line);border-radius:14px;padding:12px;font:inherit;background:#fff}
.prompt-box{white-space:pre-wrap;background:#f7faff;border:1px dashed #b5cce4;border-radius:16px;padding:14px}
.quiz-item{border:1px solid var(--line);border-radius:16px;padding:14px;margin-bottom:12px;background:#fcfdff}
.quiz-item .opts{display:grid;gap:8px;margin-top:10px}
.quiz-item label{display:flex;gap:10px;align-items:flex-start;padding:8px 10px;border:1px solid var(--line);border-radius:12px;background:#fff}
.quiz-result{font-weight:800;margin-top:12px}
.quiz-result.good{color:var(--success)}
.quiz-item.correct{border-color:#9dd9bf;background:#f3fcf7}
.quiz-item.wrong{border-color:#f2c0c0;background:#fff7f7}
.two-col{columns:2 280px;column-gap:24px}
.kbd{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;background:#eff4fb;border:1px solid #d5e0ef;border-radius:8px;padding:2px 8px;font-size:12px}
.footer-note{font-size:12px;color:var(--muted);margin-top:14px}
.muted{color:var(--muted)}
.chips{display:flex;gap:8px;flex-wrap:wrap}
.chip{padding:6px 10px;border-radius:999px;background:#eef5ff;color:#18477f;font-size:12px;font-weight:700}
.toast{position:fixed;right:24px;bottom:24px;background:#16375f;color:#fff;padding:12px 14px;border-radius:14px;box-shadow:var(--shadow);z-index:99}
.mobile-toggle{display:none}
@media (max-width: 980px){
 body{display:block}
 .sidebar{position:fixed;left:0;top:0;bottom:0;z-index:50;transform:translateX(-100%);transition:.25s}
 .sidebar.open{transform:translateX(0)}
 .main{height:100vh}
 .mobile-toggle{display:inline-block}
 .dashboard,.grid2,.meta-grid{grid-template-columns:1fr}
 #pageWrap{padding:14px}
 .topbar{gap:8px;padding:10px 12px}
 .topbar button{padding:9px 10px}
 .title{font-size:14px}
 .subtitleline{display:none}
}