/* =========================================================
   EduCore ERP — Redesign
   Design language: calm slate + indigo accent, generous
   spacing, soft elevation. Sticky header + sticky sub-nav.
   ========================================================= */

:root{
  --ink-900:#0f172a;
  --ink-700:#334155;
  --ink-500:#64748b;
  --ink-300:#cbd5e1;
  --ink-100:#f1f5f9;
  --surface:#ffffff;
  --bg:#f6f7fb;
  --accent:#4f46e5;
  --accent-dark:#4338ca;
  --accent-soft:#eef2ff;
  --success:#16a34a;
  --warning:#d97706;
  --danger:#dc2626;
  --radius:12px;
  --shadow-sm:0 1px 2px rgba(15,23,42,.06);
  --shadow-md:0 8px 24px rgba(15,23,42,.08);
  --header-h:64px;
  --subnav-h:48px;
  --sidebar-w:248px;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

*{box-sizing:border-box;}
html,body{margin:0;padding:0;}
body{
  font-family:var(--font);
  background:var(--bg);
  color:var(--ink-900);
  font-size:14.5px;
  line-height:1.5;
}
a{color:inherit;text-decoration:none;}
img{max-width:100%;display:block;}

/* ---------------------------------------------------------
   STICKY TOP HEADER
   --------------------------------------------------------- */
.app-header{
  position:sticky;
  top:0;
  z-index:100;
  height:var(--header-h);
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  padding:0 20px;
  background:var(--surface);
  border-bottom:1px solid var(--ink-100);
  box-shadow:var(--shadow-sm);
}
.app-header .brand{
  display:flex;
  align-items:center;
  gap:10px;
  font-weight:700;
  font-size:17px;
  color:var(--ink-900);
  white-space:nowrap;
}
.app-header .brand .logo-dot{
  width:32px;height:32px;border-radius:9px;
  background:linear-gradient(135deg,var(--accent),#818cf8);
  display:flex;align-items:center;justify-content:center;
  color:#fff;font-weight:800;font-size:15px;
}
.app-header .header-search{
  flex:1;
  max-width:420px;
  display:flex;
  align-items:center;
  background:var(--ink-100);
  border-radius:999px;
  padding:8px 14px;
  gap:8px;
  color:var(--ink-500);
}
.app-header .header-search input{
  border:0;background:transparent;outline:0;width:100%;font-size:13.5px;color:var(--ink-900);
}
.app-header .header-actions{
  display:flex;align-items:center;gap:14px;
}
.header-icon-btn{
  width:38px;height:38px;border-radius:10px;
  display:flex;align-items:center;justify-content:center;
  background:var(--ink-100);color:var(--ink-700);
  cursor:pointer;position:relative;border:0;
}
.header-icon-btn .badge{
  position:absolute;top:-4px;right:-4px;
  background:var(--danger);color:#fff;
  font-size:10px;font-weight:700;
  min-width:16px;height:16px;border-radius:8px;
  display:flex;align-items:center;justify-content:center;
  padding:0 3px;
}
.user-chip{
  display:flex;align-items:center;gap:8px;
  padding:6px 10px 6px 6px;border-radius:999px;
  background:var(--ink-100);cursor:pointer;
}
.user-chip img,.user-chip .avatar{
  width:28px;height:28px;border-radius:50%;
  background:var(--accent-soft);color:var(--accent-dark);
  display:flex;align-items:center;justify-content:center;
  font-weight:700;font-size:12px;
}
.user-chip .role-tag{font-size:11px;color:var(--ink-500);}

/* ---------------------------------------------------------
   STICKY SECONDARY MODULE NAV (horizontal, scrolls under header)
   --------------------------------------------------------- */
.app-subnav{
  position:sticky;
  top:var(--header-h);
  z-index:90;
  height:var(--subnav-h);
  background:var(--surface);
  border-bottom:1px solid var(--ink-100);
  display:flex;
  align-items:center;
  gap:4px;
  padding:0 16px;
  overflow-x:auto;
  scrollbar-width:none;
}
.app-subnav::-webkit-scrollbar{display:none;}
.app-subnav a{
  white-space:nowrap;
  padding:8px 14px;
  border-radius:8px;
  font-size:13px;
  font-weight:600;
  color:var(--ink-500);
}
.app-subnav a.active,
.app-subnav a:hover{
  background:var(--accent-soft);
  color:var(--accent-dark);
}

/* ---------------------------------------------------------
   LAYOUT: fixed sidebar + content
   --------------------------------------------------------- */
.app-shell{display:flex;min-height:100vh;}
.app-sidebar{
  width:var(--sidebar-w);
  flex-shrink:0;
  background:var(--surface);
  border-right:1px solid var(--ink-100);
  position:sticky;
  top:var(--header-h);
  height:calc(100vh - var(--header-h));
  overflow-y:auto;
  padding:16px 10px;
}
.sidebar-group{margin-bottom:18px;}
.sidebar-group-title{
  font-size:11px;font-weight:700;letter-spacing:.06em;
  color:var(--ink-500);text-transform:uppercase;
  padding:0 10px;margin-bottom:6px;
}
.sidebar-link{
  display:flex;align-items:center;gap:10px;
  padding:9px 10px;border-radius:9px;
  font-size:13.5px;font-weight:500;color:var(--ink-700);
  margin-bottom:2px;
}
.sidebar-link:hover{background:var(--ink-100);}
.sidebar-link.active{
  background:var(--accent-soft);color:var(--accent-dark);font-weight:700;
}
.sidebar-link .icon{width:18px;text-align:center;color:var(--ink-500);}
.sidebar-link.active .icon{color:var(--accent);}

.app-main{flex:1;min-width:0;padding:24px;}

/* ---------------------------------------------------------
   COMPONENTS
   --------------------------------------------------------- */
.page-head{
  display:flex;align-items:center;justify-content:space-between;
  margin-bottom:20px;flex-wrap:wrap;gap:10px;
}
.page-head h1{font-size:20px;margin:0 0 2px;}
.page-head .breadcrumb{font-size:12.5px;color:var(--ink-500);}

.card{
  background:var(--surface);border-radius:var(--radius);
  box-shadow:var(--shadow-sm);border:1px solid var(--ink-100);
  padding:20px;
}
.stat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:16px;margin-bottom:22px;}
.stat-card{
  background:var(--surface);border-radius:var(--radius);
  padding:18px;border:1px solid var(--ink-100);box-shadow:var(--shadow-sm);
  display:flex;align-items:center;gap:14px;
}
.stat-card .stat-icon{
  width:44px;height:44px;border-radius:11px;
  display:flex;align-items:center;justify-content:center;
  font-size:18px;color:#fff;flex-shrink:0;
}
.stat-card .stat-value{font-size:21px;font-weight:800;}
.stat-card .stat-label{font-size:12px;color:var(--ink-500);}

.btn{
  display:inline-flex;align-items:center;gap:6px;
  padding:9px 16px;border-radius:9px;border:0;
  font-size:13.5px;font-weight:600;cursor:pointer;
}
.btn-primary{background:var(--accent);color:#fff;}
.btn-primary:hover{background:var(--accent-dark);}
.btn-outline{background:#fff;color:var(--ink-700);border:1px solid var(--ink-300);}
.btn-danger{background:var(--danger);color:#fff;}
.btn-sm{padding:6px 10px;font-size:12.5px;}

.table-wrap{overflow-x:auto;}
table.data-table{width:100%;border-collapse:collapse;font-size:13.5px;}
table.data-table th{
  text-align:left;padding:10px 12px;background:var(--ink-100);
  color:var(--ink-700);font-weight:700;font-size:12px;
  text-transform:uppercase;letter-spacing:.03em;
}
table.data-table td{padding:10px 12px;border-bottom:1px solid var(--ink-100);}
table.data-table tr:hover td{background:#fafbff;}

.badge-status{padding:3px 9px;border-radius:999px;font-size:11.5px;font-weight:700;}
.badge-success{background:#dcfce7;color:var(--success);}
.badge-warning{background:#fef3c7;color:var(--warning);}
.badge-danger{background:#fee2e2;color:var(--danger);}
.badge-muted{background:var(--ink-100);color:var(--ink-500);}

.form-group{margin-bottom:14px;}
.form-group label{display:block;font-size:12.5px;font-weight:600;color:var(--ink-700);margin-bottom:5px;}
.form-control{
  width:100%;padding:9px 12px;border:1px solid var(--ink-300);
  border-radius:8px;font-size:13.5px;font-family:var(--font);
}
.form-control:focus{outline:0;border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft);}
.form-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px;}

.auth-wrap{
  min-height:100vh;display:flex;align-items:center;justify-content:center;
  background:linear-gradient(135deg,#eef2ff 0%,#f6f7fb 60%);
}
.auth-card{width:380px;background:#fff;border-radius:16px;box-shadow:var(--shadow-md);padding:32px;}
.auth-card h1{font-size:19px;margin:0 0 4px;}
.auth-card p.sub{color:var(--ink-500);font-size:13px;margin:0 0 22px;}

/* responsive */
@media (max-width: 860px){
  .app-sidebar{display:none;}
  .app-header .header-search{display:none;}
}