/* ==========================================================
   STEAMLAB LMS - DISEÑO MODERNO
   Gama azul rey / azul profundo
   ========================================================== */

:root{
  --royal-900:#0a1f4d;
  --royal-800:#0d2a6b;
  --royal-700:#123a8f;
  --royal-600:#1a4bb5;
  --royal-500:#2563eb;
  --royal-400:#3b82f6;
  --royal-300:#60a5fa;
  --royal-100:#dbeafe;

  --bg:#f4f7fd;
  --surface:#ffffff;
  --surface-2:#eef3ff;
  --border:#d8e2f5;
  --text:#10214a;
  --muted:#5f7392;

  --gold:#f5b301;
  --success:#10b981;
  --danger:#ef4444;
  --violet:#7c3aed;

  --radius:18px;
  --radius-sm:12px;
  --shadow:0 18px 40px rgba(13,42,107,.12);
  --shadow-sm:0 8px 22px rgba(13,42,107,.08);
}

*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:'Inter','Segoe UI',system-ui,-apple-system,Arial,sans-serif;
  background:
    radial-gradient(1100px 500px at 85% -10%, rgba(37,99,235,.18), transparent 60%),
    radial-gradient(800px 420px at -10% 10%, rgba(124,58,237,.10), transparent 60%),
    var(--bg);
  color:var(--text);
  min-height:100vh;
}

a{color:var(--royal-600);text-decoration:none}
a:hover{color:var(--royal-800)}

/* ---------- Botones ---------- */
button,.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  border:0;cursor:pointer;text-decoration:none;
  padding:11px 18px;border-radius:999px;
  font-size:14px;font-weight:700;letter-spacing:.01em;
  background:linear-gradient(135deg,var(--royal-600),var(--royal-800));
  color:#fff;box-shadow:0 10px 24px rgba(26,75,181,.25);
  transition:.2s ease;
}
button:hover,.btn:hover{transform:translateY(-1px);box-shadow:0 14px 30px rgba(26,75,181,.32)}
.btn.ghost{
  background:rgba(255,255,255,.75);color:var(--royal-800);
  border:1px solid var(--border);box-shadow:none;
}
.btn.ghost:hover{background:#fff}
.btn.secondary{
  background:var(--surface-2);color:var(--royal-800);
  border:1px solid var(--border);box-shadow:none;
}
.btn.danger{
  background:linear-gradient(135deg,#f87171,var(--danger));
  box-shadow:0 10px 22px rgba(239,68,68,.22);
}
.btn.full{width:100%}
.btn.sm{padding:8px 13px;font-size:13px}

/* ---------- Formularios ---------- */
label{
  display:block;margin:16px 0 7px;
  font-size:11.5px;font-weight:800;letter-spacing:.09em;
  text-transform:uppercase;color:var(--muted);
}
input,select,textarea{
  width:100%;padding:13px 15px;font-size:14.5px;color:var(--text);
  background:#fff;border:1.6px solid var(--border);
  border-radius:var(--radius-sm);outline:none;transition:.18s;
}
input:focus,select:focus,textarea:focus{
  border-color:var(--royal-500);
  box-shadow:0 0 0 4px rgba(37,99,235,.13);
}
textarea{min-height:120px;resize:vertical}
input[type="file"]{padding:10px;background:var(--surface-2)}

/* ---------- Login ---------- */
.auth-body{
  display:grid;place-items:center;min-height:100vh;padding:24px;
}
.auth-card{
  width:min(460px,100%);
  background:rgba(255,255,255,.92);
  border:1px solid rgba(255,255,255,.7);
  border-radius:26px;padding:36px;
  box-shadow:0 30px 70px rgba(10,31,77,.22);
  backdrop-filter:blur(14px);
}
.auth-card .brand{margin-bottom:22px}
.auth-title{
  font-size:25px;font-weight:900;color:var(--royal-900);
  margin-bottom:6px;
}
.auth-sub{color:var(--muted);font-size:14px;margin-bottom:8px}

/* ---------- Marca ---------- */
.brand{display:flex;align-items:center;gap:12px}
.logo{
  width:44px;height:44px;border-radius:14px;
  display:grid;place-items:center;color:#fff;font-weight:900;font-size:19px;
  background:linear-gradient(135deg,var(--royal-500),var(--royal-800) 65%,var(--violet));
  box-shadow:0 10px 24px rgba(26,75,181,.35);
}
.brand b{display:block;font-size:17px;color:var(--royal-900);line-height:1.1}
.brand small{color:var(--muted);font-size:12px}

/* ---------- Barra superior ---------- */
.topbar{
  position:sticky;top:0;z-index:50;
  display:flex;align-items:center;justify-content:space-between;gap:16px;
  padding:14px clamp(18px,4vw,38px);
  background:linear-gradient(90deg,rgba(10,31,77,.97),rgba(18,58,143,.96));
  color:#fff;
  box-shadow:0 12px 30px rgba(10,31,77,.22);
}
.topbar .brand b{color:#fff}
.topbar .brand small{color:rgba(219,234,254,.75)}
.topbar .logo{background:linear-gradient(135deg,#60a5fa,#2563eb);box-shadow:0 8px 20px rgba(0,0,0,.25)}
.user-box{display:flex;align-items:center;gap:14px;font-size:14px;color:rgba(219,234,254,.9)}
.user-box .btn.ghost{
  background:rgba(255,255,255,.12);color:#fff;
  border-color:rgba(255,255,255,.25);
}
.user-box .btn.ghost:hover{background:rgba(255,255,255,.2)}

/* ---------- Layout ---------- */
.layout{
  display:grid;
  grid-template-columns:272px minmax(0,1fr);
  min-height:calc(100vh - 73px);
}
@media(max-width:950px){
  .layout{grid-template-columns:1fr}
  .sidebar{display:none}
}

/* ---------- Menú lateral ---------- */
.sidebar{
  padding:24px 18px;
  background:linear-gradient(180deg,#fff, #f7faff);
  border-right:1px solid var(--border);
}
.sidebar .side-title{
  font-size:11px;font-weight:800;letter-spacing:.12em;
  text-transform:uppercase;color:var(--muted);
  margin:0 10px 14px;
}
.sidebar nav{display:flex;flex-direction:column;gap:7px}
.sidebar a{
  display:flex;align-items:center;gap:11px;
  padding:12px 14px;border-radius:14px;
  color:var(--muted);font-weight:650;font-size:14.5px;
  border:1px solid transparent;transition:.18s;
}
.sidebar a::before{
  content:"";width:8px;height:8px;border-radius:50%;
  background:var(--royal-300);transition:.18s;
}
.sidebar a:hover{
  color:var(--royal-800);background:var(--surface-2);
  border-color:var(--border);transform:translateX(2px);
}
.sidebar a.active{
  color:#fff;background:linear-gradient(135deg,var(--royal-600),var(--royal-800));
  box-shadow:0 12px 26px rgba(26,75,181,.28);
}
.sidebar a.active::before{background:var(--gold)}

/* ---------- Contenido ---------- */
.content{padding:clamp(20px,4vw,40px)}
.page-head{
  display:flex;align-items:flex-end;justify-content:space-between;
  gap:18px;margin-bottom:24px;flex-wrap:wrap;
}
h1{
  font-size:clamp(25px,3vw,34px);font-weight:900;
  color:var(--royal-900);letter-spacing:-.02em;
}
h2{font-size:20px;font-weight:850;color:var(--royal-900);margin-bottom:16px}
h3{font-size:17px;font-weight:800;color:var(--royal-900)}
p{line-height:1.55}

/* ---------- Tarjetas ---------- */
.card{
  background:var(--surface);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:24px;margin-bottom:22px;
  box-shadow:var(--shadow-sm);
}
.card.hero{
  position:relative;overflow:hidden;
  background:linear-gradient(135deg,var(--royal-800),var(--royal-600) 55%,var(--violet));
  color:#fff;border:0;
}
.card.hero h1,.card.hero h2,.card.hero h3{color:#fff}
.card.hero p{color:rgba(219,234,254,.85)}
.card.hero::after{
  content:"";position:absolute;right:-70px;top:-80px;
  width:260px;height:260px;border-radius:50%;
  background:rgba(255,255,255,.10);
}
.item{
  background:var(--surface-2);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  padding:17px;margin-bottom:14px;
  transition:.18s;
}
.item:hover{
  transform:translateY(-2px);
  box-shadow:var(--shadow-sm);
  border-color:var(--royal-300);
}
.item b{color:var(--royal-900)}
.mut{color:var(--muted);font-size:13.5px}

/* ---------- KPI ---------- */
.kpi{
  position:relative;overflow:hidden;
  display:flex;flex-direction:column;gap:6px;
}
.kpi b{
  font-size:34px;font-weight:900;color:var(--royal-800);
  letter-spacing:-.03em;
}
.kpi span{color:var(--muted);font-size:13px;font-weight:650}
.kpi::after{
  content:"";position:absolute;right:-25px;bottom:-30px;
  width:110px;height:110px;border-radius:50%;
  background:linear-gradient(135deg,rgba(37,99,235,.14),rgba(124,58,237,.10));
}

/* ---------- Grids ---------- */
.grid{display:grid;gap:20px}
.grid-2{grid-template-columns:2fr 1fr}
.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}
.grid-4{grid-template-columns:repeat(4,minmax(0,1fr))}
@media(max-width:1150px){.grid-4{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:1000px){.grid-2,.grid-3{grid-template-columns:1fr}}
@media(max-width:640px){.grid-4{grid-template-columns:1fr}}

/* ---------- Tablas ---------- */
.table-wrap{overflow-x:auto;border-radius:var(--radius-sm)}
table{width:100%;border-collapse:collapse;font-size:14.5px;min-width:620px}
th{
  text-align:left;padding:13px 14px;
  color:var(--royal-800);font-size:11.5px;font-weight:800;
  text-transform:uppercase;letter-spacing:.08em;
  background:var(--surface-2);
}
td{padding:14px;border-bottom:1px solid var(--border);vertical-align:middle}
tr:last-child td{border-bottom:0}
tbody tr:hover{background:#f8fbff}

/* ---------- Etiquetas ---------- */
.pill{
  display:inline-flex;align-items:center;gap:6px;
  padding:5px 12px;border-radius:999px;
  font-size:11.5px;font-weight:800;
}
.pill.administrador{background:#fef3c7;color:#92400e}
.pill.profesor{background:var(--royal-100);color:var(--royal-800)}
.pill.estudiante{background:#ede9fe;color:#5b21b6}
.pill.activo{background:#d1fae5;color:#065f46}
.pill.inactivo{background:#fee2e2;color:#991b1b}

/* ---------- Alertas ---------- */
.alert{
  display:flex;align-items:center;gap:10px;
  padding:14px 17px;border-radius:14px;margin-bottom:20px;
  font-weight:700;font-size:14px;
}
.alert.success{
  background:#ecfdf5;color:#065f46;
  border:1px solid #a7f3d0;
}
.alert.error{
  background:#fef2f2;color:#991b1b;
  border:1px solid #fecaca;
}

/* ---------- Formulario en tarjeta ---------- */
.form-actions{
  display:flex;justify-content:flex-end;gap:12px;
  margin-top:22px;flex-wrap:wrap;
}
.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:0 18px}
@media(max-width:700px){.form-grid{grid-template-columns:1fr}}

/* ---------- Enlaces de sesión ---------- */
.session-link{
  display:inline-flex;align-items:center;gap:8px;
  margin-top:8px;font-weight:750;
}
.session-link::before{content:"▶";font-size:11px;color:var(--royal-600)}