:root {
  --bg: #f3f6fb;
  --surface: #ffffff;
  --surface-2: #f8fbff;
  --text: #112033;
  --muted: #64748b;
  --primary: #2563eb;
  --primary-soft: #dbeafe;
  --border: #dbe3ef;
  --success: #16a34a;
  --danger: #dc2626;
  --shadow: 0 16px 40px rgba(15, 23, 42, 0.08);
  --radius: 20px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; font-family: 'Inter', sans-serif; background: var(--bg); color: var(--text); }
button, input, select { font: inherit; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.app-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 280px 1fr;
}

.sidebar {
  background: linear-gradient(180deg, #0f172a 0%, #111827 100%);
  color: white;
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 24px;
  position: sticky;
  top: 0;
  height: 100vh;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 28px;
}

.brand-mark {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
  font-weight: 800;
  font-size: 1.1rem;
}

.brand h1, .panel h3, .topbar h2 { margin: 0; }
.brand p, .muted, .sidebar-footer { color: rgba(255,255,255,0.7); margin: 4px 0 0; }
.nav-links { display: grid; gap: 10px; }
.nav-link {
  border: 1px solid rgba(255,255,255,0.08);
  color: white;
  background: rgba(255,255,255,0.04);
  padding: 14px 16px;
  border-radius: 14px;
  text-align: left;
  cursor: pointer;
  transition: 0.2s ease;
}
.nav-link:hover, .nav-link.active {
  background: rgba(37, 99, 235, 0.28);
  border-color: rgba(96, 165, 250, 0.5);
}

.main-content {
  padding: 28px;
  overflow-x: hidden;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px;
  margin-bottom: 22px;
}

.section { display: none; }
.section.active { display: block; }
.card-grid {
  display: grid;
  gap: 18px;
}
.metrics-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin-bottom: 20px;
}
.dashboard-grid {
  grid-template-columns: 1.1fr 1fr;
}
.metric-card, .panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.metric-card {
  padding: 22px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.metric-card span, .metric-card small { color: var(--muted); }
.metric-card strong { font-size: 1.8rem; }
.metric-card.accent {
  background: linear-gradient(135deg, #eff6ff 0%, #ecfeff 100%);
}
.panel {
  padding: 22px;
  margin-bottom: 20px;
}
.panel-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
}
.panel-head.wrap { flex-wrap: wrap; }
.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}
label {
  display: flex;
  flex-direction: column;
  gap: 8px;
  color: var(--muted);
  font-weight: 500;
}
input, select {
  border: 1px solid var(--border);
  background: var(--surface-2);
  border-radius: 14px;
  padding: 13px 14px;
  outline: none;
  color: var(--text);
}
input:focus, select:focus {
  border-color: #93c5fd;
  box-shadow: 0 0 0 4px rgba(37,99,235,0.12);
}
.form-actions, .filters {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 18px;
}
.primary-btn, .ghost-btn, .danger-btn {
  border: none;
  border-radius: 14px;
  padding: 12px 16px;
  cursor: pointer;
  transition: 0.2s ease;
}
.primary-btn {
  background: var(--primary);
  color: white;
}
.ghost-btn {
  background: white;
  border: 1px solid var(--border);
  color: var(--text);
}
.danger-btn {
  background: #fee2e2;
  color: var(--danger);
}
.primary-btn:hover, .ghost-btn:hover, .danger-btn:hover { transform: translateY(-1px); }
.table-wrap {
  overflow: auto;
  border: 1px solid var(--border);
  border-radius: 16px;
}
table {
  width: 100%;
  min-width: 980px;
  border-collapse: collapse;
  background: white;
}
th, td {
  padding: 14px 12px;
  border-bottom: 1px solid #edf2f7;
  text-align: left;
  vertical-align: top;
}
th {
  background: #f8fafc;
  color: var(--muted);
  font-size: 0.88rem;
}
.file-links {
  display: grid;
  gap: 6px;
}
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 0.8rem;
  background: #eff6ff;
  color: #1d4ed8;
}
.stats-list, .recent-activity {
  display: grid;
  gap: 12px;
}
.stat-row, .activity-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: var(--surface-2);
}
.stat-row span, .activity-row small { color: var(--muted); }
.empty-state {
  text-align: center;
  color: var(--muted);
  padding: 26px;
}

@media (max-width: 1180px) {
  .metrics-grid, .dashboard-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 920px) {
  .app-shell { grid-template-columns: 1fr; }
  .sidebar {
    position: static;
    height: auto;
    border-bottom-left-radius: 24px;
    border-bottom-right-radius: 24px;
  }
  .main-content { padding: 18px; }
}

@media (max-width: 720px) {
  .form-grid, .metrics-grid, .dashboard-grid { grid-template-columns: 1fr; }
  .topbar { flex-direction: column; align-items: stretch; }
  .nav-links { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .nav-link { text-align: center; }
  .panel, .metric-card { padding: 18px; }
}