/* NIXUS Course Lesson - Calm teal/sage theme */
*{margin:0;padding:0;box-sizing:border-box}
body{background:#F7F9FB;color:#2C3E44;font-family:'Plus Jakarta Sans',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;line-height:1.7;min-height:100vh}

/* Top nav */
.topbar{background:#fff;border-bottom:1px solid #D4DFE3;padding:12px 20px;display:flex;align-items:center;gap:16px;position:sticky;top:0;z-index:100}
.topbar a{color:#4A7C8A;text-decoration:none;font-size:14px;font-weight:600}
.topbar .back{display:flex;align-items:center;gap:6px}
.topbar .back:hover{color:#3A5F6A}
.topbar .sep{color:#D4DFE3}
.topbar .module{color:#5F7177;font-size:13px}
.topbar .lesson-title{color:#2C3E44;font-size:14px;font-weight:600;margin-left:auto}

/* Hero */
.lesson-hero{background:linear-gradient(135deg,#4A7C8A 0%,#3A5F6A 100%);color:#fff;padding:60px 20px 50px;text-align:center}
.lesson-hero .tag{display:inline-block;font-size:11px;letter-spacing:2px;text-transform:uppercase;color:#C5DAE0;border:1px solid rgba(255,255,255,0.2);padding:4px 14px;border-radius:20px;margin-bottom:16px}
.lesson-hero h1{font-family:'Space Grotesk',sans-serif;font-size:clamp(28px,5vw,42px);font-weight:700;margin-bottom:12px;line-height:1.2}
.lesson-hero .meta{font-size:14px;color:#C5DAE0;display:flex;justify-content:center;gap:20px;flex-wrap:wrap}
.lesson-hero .meta span{display:flex;align-items:center;gap:6px}

/* Content container */
.content{max-width:780px;margin:0 auto;padding:40px 20px 80px}

/* Section cards */
.section{background:#fff;border-radius:12px;padding:32px;margin-bottom:24px;border:1px solid #E8F0F2;box-shadow:0 1px 3px rgba(0,0,0,0.04)}
.section h2{font-family:'Space Grotesk',sans-serif;font-size:22px;font-weight:700;color:#2C3E44;margin-bottom:16px;padding-bottom:12px;border-bottom:2px solid #E8F0F2}
.section h3{font-size:17px;font-weight:600;color:#4A7C8A;margin:20px 0 10px}
.section p{margin-bottom:14px;color:#3D5158;font-size:15px}
.section ul,.section ol{margin:12px 0 16px 24px}
.section li{margin-bottom:8px;color:#3D5158;font-size:15px}
.section li strong{color:#2C3E44}

/* Comparison cards */
.compare-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:16px;margin:20px 0}
.compare-card{background:#F7F9FB;border-radius:10px;padding:20px;border-left:4px solid #4A7C8A}
.compare-card.green{border-left-color:#6B9E7A;background:#F5FAF6}
.compare-card.warm{border-left-color:#E8A87C;background:#FFF8F3}
.compare-card h4{font-size:15px;font-weight:700;color:#2C3E44;margin-bottom:8px}
.compare-card p{font-size:13px;color:#5F7177;margin:0}

/* Info boxes */
.info-box{background:#E8F0F2;border-radius:10px;padding:20px 24px;margin:20px 0;border-left:4px solid #4A7C8A}
.info-box.tip{background:#E5F0E8;border-left-color:#6B9E7A}
.info-box.warn{background:#FFF4EC;border-left-color:#E8A87C}
.info-box .label{font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:1px;color:#4A7C8A;margin-bottom:6px}
.info-box.tip .label{color:#6B9E7A}
.info-box.warn .label{color:#D4654A}
.info-box p{margin:0;font-size:14px;color:#3D5158}

/* Visual table */
.vis-table{width:100%;border-collapse:separate;border-spacing:0;margin:20px 0;border-radius:10px;overflow:hidden;border:1px solid #E8F0F2}
.vis-table th{background:#4A7C8A;color:#fff;padding:12px 16px;text-align:left;font-size:13px;font-weight:600}
.vis-table td{padding:10px 16px;font-size:14px;color:#3D5158;border-bottom:1px solid #E8F0F2}
.vis-table tr:last-child td{border-bottom:none}
.vis-table tr:nth-child(even) td{background:#F7F9FB}
.vis-table .check{color:#6B9E7A;font-weight:700}
.vis-table .cross{color:#D4654A}

/* Code blocks */
.code-block{background:#1E2D33;border-radius:10px;padding:20px;margin:16px 0;overflow-x:auto}
.code-block code{font-family:'DM Mono',monospace;font-size:13px;color:#C5DAE0;line-height:1.6}
.code-block .comment{color:#5F7177}

/* Key takeaway */
.takeaway{background:linear-gradient(135deg,#4A7C8A,#3A5F6A);border-radius:12px;padding:28px;margin:24px 0;color:#fff}
.takeaway h3{font-family:'Space Grotesk',sans-serif;font-size:20px;margin-bottom:12px;color:#fff}
.takeaway ul{margin:0 0 0 20px}
.takeaway li{color:#E0EEF2;margin-bottom:6px;font-size:15px}

/* Bottom nav */
.lesson-nav{display:flex;justify-content:space-between;align-items:center;padding:24px 0;border-top:1px solid #E8F0F2;margin-top:40px}
.lesson-nav a{display:flex;align-items:center;gap:8px;color:#4A7C8A;text-decoration:none;font-weight:600;font-size:14px;padding:10px 20px;border-radius:8px;border:1px solid #D4DFE3;transition:all 0.2s}
.lesson-nav a:hover{background:#E8F0F2;border-color:#4A7C8A}
.lesson-nav .next{background:#4A7C8A;color:#fff;border-color:#4A7C8A}
.lesson-nav .next:hover{background:#3A5F6A}

/* Share/download bar */
.share-bar{display:flex;gap:10px;justify-content:center;margin:30px 0;flex-wrap:wrap}
.share-bar a,.share-bar button{display:inline-flex;align-items:center;gap:6px;padding:8px 18px;border-radius:8px;font-size:13px;font-weight:600;text-decoration:none;cursor:pointer;border:1px solid #D4DFE3;background:#fff;color:#4A7C8A;transition:all 0.2s}
.share-bar a:hover,.share-bar button:hover{background:#E8F0F2;border-color:#4A7C8A}

/* Responsive */
@media(max-width:600px){
    .section{padding:20px 16px}
    .compare-grid{grid-template-columns:1fr}
    .lesson-hero{padding:40px 16px 30px}
}

/* Print/download styles */
@media print{
    .topbar,.share-bar,.lesson-nav{display:none!important}
    body{background:#fff}
    .section{box-shadow:none;border:1px solid #ddd;page-break-inside:avoid}
}