:root {
    --bg: #f2f4f8;
    --sidebar-bg: #1c2431;
    --topbar-bg: #fff;
    --accent: #0077ff;
    --text: #333;
    --radius: 1rem;
    --gap: 1.25rem;
    --danger: #e74c3c;
}
* { box-sizing: border-box; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    background: var(--bg);
    color: var(--text);
}
.app-shell { display: flex; flex-direction: column; min-height: 100vh; }
.topbar {
    display: flex; justify-content: space-between; align-items: center;
    background: var(--topbar-bg);
    padding: .75rem 1.5rem; border-bottom: 1px solid rgba(0,0,0,.05);
}
.topbar .logo a { text-decoration: none; font-weight: 600; color: var(--text); }
.topbar-actions { display: flex; gap: .75rem; align-items: center; }
.app-body { display: flex; flex: 1; min-height: 0; }
.sidebar { width: 230px; background: var(--sidebar-bg); color: #fff; padding: 1rem .5rem; }
.sidebar ul { list-style: none; padding: 0; margin: 0; }
.sidebar li a {
    display: block; padding: .5rem 1rem; border-radius: .5rem; color: #c7d1de; text-decoration: none;
}
.sidebar li.active a, .sidebar li a:hover { background: rgba(255,255,255,.1); color: #fff; }
.app-content { flex: 1; padding: 1.5rem 1.5rem 3.5rem; overflow-y: auto; }
.page-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 1.25rem; }
.cards-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px,1fr)); gap: 1rem; margin-bottom: 1.5rem; }
.card { background: #fff; border-radius: var(--radius); padding: 1rem; box-shadow: 0 10px 30px rgba(15,23,42,.05); }
.card h2 { margin: 0; font-size: 1.8rem; }
.card p { margin: .25rem 0 .5rem; color: #8492a6; }
.card .link { text-decoration: none; font-weight: 500; color: var(--accent); }
.table { width: 100%; border-collapse: collapse; background: #fff; border-radius: 1rem; overflow: hidden; }
.table th, .table td { padding: .6rem .75rem; border-bottom: 1px solid rgba(0,0,0,.035); }
.table th { background: rgba(60,80,100,.03); text-align: left; }
.btn {
    display: inline-flex; align-items: center; gap: .25rem; padding: .45rem .8rem;
    border-radius: .5rem; border: none; background: var(--accent); color: #fff;
    text-decoration: none; cursor: pointer; font-weight: 500;
}
.btn-outline { background: transparent; border: 1px solid rgba(0,0,0,.1); color: #333; }
.btn-sm { padding: .25rem .6rem; font-size: .75rem; }
.form-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px,1fr)); gap: 1rem 1.5rem; background: #fff; padding: 1rem; border-radius: 1rem; }
.form-grid label { display: flex; flex-direction: column; gap: .35rem; font-size: .85rem; }
input, select, textarea { border: 1px solid rgba(0,0,0,.1); border-radius: .5rem; padding: .4rem .5rem; font-size: .9rem; }
textarea { min-height: 80px; }
.panel-grid { display: grid; grid-template-columns: 1.4fr .9fr; gap: 1rem; }
.panel { background: #fff; border-radius: 1rem; padding: 1rem; }
.tree { list-style: none; padding-left: 1rem; }
.tree > li { margin-bottom: .5rem; }
.tree-node { font-weight: 500; }
.badge { display: inline-block; background: rgba(0,119,255,.12); color: #0051cc; padding: .15rem .3rem; border-radius: .35rem; font-size: .7rem; text-decoration: none; }
.app-footer { text-align: center; padding: .85rem; background: #fff; border-top: 1px solid rgba(0,0,0,.03); }
.login-page { display: flex; height: 100vh; background: radial-gradient(circle at top, #e6f0ff, #fff); justify-content: center; align-items: center; }
.login-card { background: #fff; padding: 2rem 2.5rem; border-radius: 1.25rem; box-shadow: 0 18px 40px rgba(15,23,42,.08); width: min(380px, 100%); }
.alert { background: rgba(231,76,60,.09); border: 1px solid rgba(231,76,60,.35); padding: .5rem .75rem; border-radius: .5rem; margin-bottom: .5rem; }
@media (max-width: 900px) {
    .panel-grid { grid-template-columns: 1fr; }
    .sidebar { display: none; }
    .app-content { padding: 1rem .75rem 3.5rem; }
}