:root{
  --bg:#f5f7fb;
  --card:#fff;
  --text:#172033;
  --muted:#64748b;
  --primary:#153e75;
  --primary-2:#2457a6;
  --ok:#0f9d58;
  --error:#b3261e;
  --border:#dde5f0;
  --shadow:0 10px 25px rgba(23,32,51,.08);
  --radius:16px;
}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--text);font-family:Arial,Helvetica,sans-serif}
a{color:var(--primary-2);text-decoration:none}
a:hover{text-decoration:underline}
.container{max-width:1200px;margin:0 auto;padding:20px}
.topbar{background:#fff;border-bottom:1px solid var(--border);position:sticky;top:0;z-index:10}
.topbar-inner{display:flex;align-items:center;justify-content:space-between}
.brand{font-weight:800;font-size:20px}
.topnav{display:flex;gap:18px}
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow);margin-bottom:20px}
.narrow{max-width:520px;margin:20px auto}
.hero .card{margin-top:40px;text-align:center}
.actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:15px}
.btn,button{display:inline-flex;align-items:center;justify-content:center;gap:8px;background:var(--primary);color:#fff;border:none;border-radius:12px;padding:11px 16px;font-weight:700;cursor:pointer}
.btn.secondary,.secondary{background:#eef4ff;color:var(--primary);border:1px solid #c8d8f3}
button:hover,.btn:hover{text-decoration:none;opacity:.94}
.form-grid{display:grid;gap:14px}
.form-grid.two{grid-template-columns:repeat(2,minmax(0,1fr))}
.form-grid .full{grid-column:1/-1}
label{display:block;font-size:13px;color:var(--muted);margin-bottom:6px}
input,select,textarea{width:100%;padding:12px;border:1px solid var(--border);border-radius:12px;background:#fff}
textarea{resize:vertical}
.inline-check{display:flex;align-items:center;gap:8px;color:var(--text)}
.inline-check input{width:auto}
.alert{padding:12px 14px;border-radius:12px;margin:12px 0}
.alert.error{background:#fde8e8;color:var(--error);border:1px solid #f6c7c7}
.alert.success{background:#e8f7ef;color:var(--ok);border:1px solid #c8ead6}
.flash{max-width:1200px;margin:16px auto;padding:12px 14px;border-radius:12px}
.flash.success{background:#e8f7ef;color:var(--ok);border:1px solid #c8ead6}
.flash.error{background:#fde8e8;color:var(--error);border:1px solid #f6c7c7}
.app-shell{display:grid;grid-template-columns:260px 1fr;min-height:100vh}
.sidebar{background:linear-gradient(180deg,#0e2f57,#173c74);padding:22px;color:#fff;display:flex;flex-direction:column;gap:10px}
.sidebar h1{font-size:20px;margin:0 0 12px}
.sidebar a{color:#fff;padding:10px 12px;border-radius:12px;background:rgba(255,255,255,.08)}
.sidebar a:hover{text-decoration:none;background:rgba(255,255,255,.14)}
.sidebar-user{margin-top:auto;padding:14px;border-radius:12px;background:rgba(255,255,255,.08)}
.content{padding:24px}
.stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px;margin-bottom:20px}
.stat-card{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow)}
.stat-card strong{display:block;font-size:28px}
.stat-card span{color:var(--muted)}
table{width:100%;border-collapse:collapse;background:#fff;border-radius:12px;overflow:hidden}
th,td{padding:12px;border-bottom:1px solid var(--border);text-align:left;vertical-align:top}
th{background:#eef4ff}
tr:last-child td{border-bottom:none}
.course-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}
.course-card{border:1px solid var(--border);border-radius:14px;padding:16px;background:#fff}
.course-card img{width:100%;height:180px;object-fit:cover;border-radius:12px;margin-bottom:10px}
.progress{width:100%;height:10px;border-radius:999px;background:#eef2f7;margin:10px 0;overflow:hidden}
.progress span{display:block;height:100%;background:linear-gradient(90deg,#18a35f,#4cafef)}
.breadcrumbs{font-size:13px;color:var(--muted);margin-bottom:10px}
.video-wrap{position:relative;padding-top:56.25%;border-radius:14px;overflow:hidden;margin:14px 0;background:#000}
.video-wrap iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.lesson-image{width:100%;max-height:420px;object-fit:cover;border-radius:14px;margin:12px 0}
.lesson-content{line-height:1.7;white-space:pre-wrap}
.quiz-question{border:1px solid var(--border);border-radius:14px;padding:15px}
.radio-line{display:flex;gap:8px;align-items:center;margin-bottom:8px}
.radio-line input{width:auto}
.word-grid{display:inline-block;border:1px solid var(--border);padding:12px;border-radius:12px;background:#fff}
.word-row{display:flex}
.word-row span{display:inline-flex;width:28px;height:28px;align-items:center;justify-content:center;border:1px solid #edf1f7;font-weight:700}
.badge{display:inline-flex;padding:5px 10px;border-radius:999px;background:#eef2f7;color:var(--muted)}
.badge.ok{background:#e8f7ef;color:var(--ok)}
.inline-form{grid-template-columns:1fr auto;align-items:end}
.align-end{display:flex;align-items:end}
.certificate-page{background:#f1f4f9}
.certificate-sheet{max-width:1100px;margin:20px auto;background:#fff;min-height:720px;border:1px solid var(--border);box-shadow:var(--shadow);border-radius:16px}
.certificate-inner{text-align:center;padding:100px 80px}
.certificate-inner h1{font-size:42px;margin:0 0 30px}
.certificate-inner h2{font-size:40px;margin:15px 0}
.certificate-inner h3{font-size:32px;margin:15px 0}
.student-hero{padding:0;overflow:hidden;background:linear-gradient(90deg,#0fb6b0 0%,#1f9ed1 45%,#f4f8fc 45%,#f4f8fc 100%)}
.student-hero-inner{display:grid;grid-template-columns:1.3fr 1fr;min-height:280px}
.student-hero-copy{padding:40px;color:#fff;display:flex;flex-direction:column;justify-content:center}
.student-hero-copy h3{font-size:42px;line-height:1.1;margin:10px 0 14px;color:#fff;max-width:680px}
.student-hero-copy p{max-width:620px;font-size:17px;line-height:1.6;color:rgba(255,255,255,.95)}
.hero-badge{display:inline-flex;width:max-content;padding:8px 14px;border-radius:999px;background:rgba(255,255,255,.18);font-weight:700}
.student-hero-art{position:relative;display:flex;align-items:center;justify-content:center;background:linear-gradient(135deg,#e6f2ff,#ffffff)}
.hero-shape{width:78%;height:72%;border-radius:38% 62% 44% 56% / 46% 40% 60% 54%;background:linear-gradient(135deg,#ffffff,#e8f3ff);box-shadow:0 20px 40px rgba(25,55,100,.10)}
.course-grid-student{grid-template-columns:repeat(3,minmax(0,1fr))}
.course-card.modern{padding:0;overflow:hidden;display:flex;flex-direction:column}
.course-thumb{height:190px;background:#eaf1fb}
.course-thumb img{width:100%;height:100%;object-fit:cover;border-radius:0;margin:0}
.course-thumb-fallback{height:100%;display:flex;align-items:center;justify-content:center;background:linear-gradient(135deg,#173c74,#2457a6);color:#fff;font-size:24px;font-weight:800}
.course-card-body{padding:16px}
.course-card-body h4{margin:0 0 8px;font-size:20px}
.course-card-body p{margin:0;color:var(--muted);min-height:48px}
@media (max-width:1000px){
  .stats,.course-grid,.course-grid-student,.form-grid.two{grid-template-columns:1fr 1fr}
  .student-hero-inner{grid-template-columns:1fr}
  .student-hero-copy h3{font-size:34px}
  .student-hero-art{min-height:180px}
}
@media (max-width:760px){
  .app-shell{grid-template-columns:1fr}
  .stats,.course-grid,.course-grid-student,.form-grid.two,.inline-form{grid-template-columns:1fr}
  .topbar-inner{flex-direction:column;align-items:flex-start;gap:10px}
  .topnav{flex-wrap:wrap}
}
@media print{
  .container,.sidebar,.topbar{display:none!important}
  .certificate-sheet{margin:0;max-width:none;border:none;box-shadow:none;border-radius:0}
}