:root{
  --bg:#f4f6fb; --surface:#fff; --text:#1f2937; --muted:#6b7280;
  --border:#e2e8f0; --primary:#1f6feb; --primary-d:#1554b8;
  --green:#10b981; --red:#ef4444; --orange:#f59e0b; --purple:#8b5cf6;
  --teal:#0d9488; --sidebar:#0f2747;
  --c-dashboard:#1f6feb; --c-students:#10b981; --c-fees:#0ea5e9;
  --c-collection:#f59e0b; --c-accounts:#0d9488; --c-reports:#8b5cf6;
  --c-masters:#d946ef;
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;
  background:var(--bg);color:var(--text);font-size:14px}
a{text-decoration:none;color:inherit}

/* layout */
.layout{display:flex;min-height:100vh}
.sidebar{width:240px;background:var(--sidebar);color:#cdd9ec;
  display:flex;flex-direction:column;position:fixed;top:0;bottom:0;left:0}
.brand{display:flex;gap:10px;align-items:center;padding:18px 16px;
  border-bottom:1px solid rgba(255,255,255,.08)}
.brand-logo{background:var(--primary);color:#fff;font-weight:800;
  width:42px;height:42px;border-radius:10px;display:flex;align-items:center;
  justify-content:center;font-size:13px}
.brand-name{font-weight:700;color:#fff;font-size:15px}
.brand-sub{font-size:11px;color:#9fb2d0;margin-top:2px}
nav{flex:1;padding:10px 8px;overflow-y:auto}
.nav{display:flex;align-items:center;gap:10px;padding:11px 12px;
  border-radius:9px;color:#cdd9ec;margin-bottom:2px;font-weight:500;
  transition:background .15s}
.nav span{width:20px;text-align:center}
.nav:hover{background:rgba(255,255,255,.07)}
.nav.active{background:var(--primary);color:#fff}
.sidebar-foot{padding:10px 8px;border-top:1px solid rgba(255,255,255,.08)}
.content{margin-left:240px;flex:1;padding:14px 28px 40px;transition:margin-left .2s;position:relative}

/* sidebar collapse toggle */
.sidebar-toggle{display:inline-flex;align-items:center;justify-content:center;
  background:var(--surface);border:1px solid var(--border);border-radius:8px;
  width:40px;height:40px;font-size:18px;cursor:pointer;color:var(--text);
  box-shadow:0 1px 3px rgba(0,0,0,.08);line-height:1;margin-bottom:6px}
.sidebar-toggle:hover{background:#eef4ff}
.layout.collapsed .sidebar{transform:translateX(-100%);width:0;overflow:hidden}
.layout.collapsed .content{margin-left:0}
.accent{height:4px;margin:0 -28px 20px;background:var(--primary)}
.accent[data-c=dashboard]{background:var(--c-dashboard)}
.accent[data-c=students]{background:var(--c-students)}
.accent[data-c=fees]{background:var(--c-fees)}
.accent[data-c=collection]{background:var(--c-collection)}
.accent[data-c=accounts]{background:var(--c-accounts)}
.accent[data-c=reports]{background:var(--c-reports)}
.accent[data-c=masters]{background:var(--c-masters)}

h1{font-size:24px;margin:18px 0;font-weight:700}
h2{font-size:16px;margin:14px 0;font-weight:600}

/* cards */
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));
  gap:14px;margin-bottom:20px}
.card{background:var(--surface);border-radius:12px;padding:0;overflow:hidden;
  box-shadow:0 1px 3px rgba(0,0,0,.06);border:1px solid var(--border)}
.card .bar{height:4px}
.card .body{padding:14px 16px}
.card .val{font-size:22px;font-weight:800}
.card .lbl{font-size:12px;color:var(--muted);margin-top:3px}

.panel{background:var(--surface);border:1px solid var(--border);
  border-radius:12px;padding:18px;margin-bottom:18px;
  box-shadow:0 1px 3px rgba(0,0,0,.04)}

/* tables */
table{width:100%;border-collapse:collapse}
th{background:var(--primary);color:#fff;text-align:left;padding:10px 12px;
  font-size:13px;cursor:pointer;white-space:nowrap}
th:hover{background:var(--primary-d)}
td{padding:9px 12px;border-bottom:1px solid var(--border)}
tbody tr:nth-child(even){background:#f8fafc}
tbody tr:hover{background:#eef4ff}
.table-wrap{overflow-x:auto;border:1px solid var(--border);border-radius:10px}

/* forms & buttons */
input,select,textarea{font:inherit;padding:9px 11px;border:1px solid var(--border);
  border-radius:8px;background:#fff;width:100%}
input:focus,select:focus,textarea:focus{outline:2px solid var(--primary);
  border-color:transparent}
label{display:block;font-size:12px;color:var(--muted);margin-bottom:4px;
  margin-top:10px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;padding:9px 16px;
  border:none;border-radius:8px;font-weight:600;cursor:pointer;font-size:14px;
  background:#eef2f9;color:var(--text)}
.btn:hover{filter:brightness(.97)}
.btn-primary{background:var(--primary);color:#fff}
.btn-green{background:var(--green);color:#fff}
.btn-red{background:var(--red);color:#fff}
.btn-ghost{background:#fff;border:1px solid var(--border)}
.btn:disabled{opacity:.5;cursor:not-allowed}
.row{display:flex;gap:12px;flex-wrap:wrap;align-items:flex-end}
.row>div{flex:1;min-width:140px}

/* pagination */
.pager{display:flex;align-items:center;gap:12px;margin-top:12px}
.pager .count{margin-left:auto;color:var(--muted);font-size:13px}

/* toolbar */
.toolbar{display:flex;gap:10px;align-items:center;margin-bottom:14px;
  flex-wrap:wrap}
.toolbar .search{flex:1;max-width:280px}

/* modal */
.modal-bg{position:fixed;inset:0;background:rgba(15,30,55,.55);
  display:none;align-items:center;justify-content:center;z-index:50;padding:20px}
.modal-bg.open{display:flex}
.modal{background:#fff;border-radius:14px;width:100%;max-width:560px;
  max-height:90vh;display:flex;flex-direction:column;overflow:hidden}
.modal-head{padding:16px 20px;font-weight:700;font-size:16px;color:#fff;
  background:var(--primary)}
.modal-body{padding:18px 20px;overflow-y:auto}
.modal-foot{padding:14px 20px;border-top:1px solid var(--border);
  display:flex;justify-content:flex-end;gap:10px;background:#fafbfc}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:0 14px}

/* badges */
.badge{padding:3px 9px;border-radius:20px;font-size:12px;font-weight:600}
.badge.Credit,.badge.Active,.badge.Yes{background:#dcfce7;color:#166534}
.badge.Debit{background:#fee2e2;color:#991b1b}
.badge.Corrected{background:#fef3c7;color:#92400e}
.badge.Voided,.badge.No{background:#f1f5f9;color:#64748b}

/* flash */
.flash{padding:11px 16px;border-radius:8px;margin-bottom:14px;font-weight:500}
.flash.error{background:#fee2e2;color:#991b1b}
.flash.success{background:#dcfce7;color:#166534}

/* login */
.login-wrap{min-height:100vh;display:flex;align-items:center;
  justify-content:center;background:linear-gradient(135deg,#0f2747,#1554b8)}
.login-card{background:#fff;padding:36px;border-radius:16px;width:360px;
  box-shadow:0 20px 60px rgba(0,0,0,.3)}
.login-card h1{text-align:center;margin:6px 0 4px}
.login-card .sub{text-align:center;color:var(--muted);margin-bottom:20px;
  font-size:13px}

.muted{color:var(--muted)}
.right{text-align:right}
.tabs{display:flex;gap:4px;border-bottom:2px solid var(--border);
  margin-bottom:16px}
.tab{padding:10px 18px;cursor:pointer;font-weight:600;color:var(--muted);
  border-bottom:2px solid transparent;margin-bottom:-2px}
.tab.active{color:var(--primary);border-bottom-color:var(--primary)}
.tab-page{display:none}
.tab-page.active{display:block}
pre.stmt{background:#0f172a;color:#e2e8f0;padding:18px;border-radius:10px;
  font-size:13px;overflow-x:auto;white-space:pre-wrap}
@media(max-width:820px){
  .sidebar{width:64px}.brand-name,.brand-sub,.nav span+*{display:none}
  .content{margin-left:64px}.grid2{grid-template-columns:1fr}
}