:root {
  --brand: #d81f26;
  --brand-dark: #a5151b;
  --ink: #1f2933;
  --muted: #52606d;
  --faint: #9aa5b1;
  --border: #e4e7eb;
  --bg: #f5f6f8;
  --card: #ffffff;
  --success-bg: #d1fae5;
  --success-ink: #065f46;
  --warn-bg: #fef3c7;
  --warn-ink: #92400e;
  --danger-bg: #fee2e2;
  --danger-ink: #991b1b;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
}

a { color: inherit; text-decoration: none; }

/* ---------- Layout ---------- */
.app-shell { display: flex; min-height: 100vh; }

.sidebar {
  width: 220px;
  background: var(--ink);
  color: #fff;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  padding: 20px 0;
  position: fixed;
  top: 0; bottom: 0; left: 0;
  overflow-y: auto;
  z-index: 50;
  transition: transform 0.2s ease;
}

.sidebar .brand { padding: 0 20px 20px 20px; font-size: 18px; font-weight: 700; border-bottom: 1px solid #33404a; margin-bottom: 12px; }
.sidebar .brand span { color: var(--brand); }

.sidebar nav a {
  display: flex; align-items: center; gap: 10px;
  padding: 12px 20px; font-size: 14px; color: #cbd2d9;
}
.sidebar nav a:hover { background: #2b3640; color: #fff; }
.sidebar nav a.active { background: var(--brand); color: #fff; }

.main {
  flex: 1;
  margin-left: 220px;
  padding: 24px 28px 60px 28px;
  max-width: 1200px;
}

.topbar { display: flex; justify-content: space-between; align-items: center; margin-bottom: 24px; flex-wrap: wrap; gap: 12px; }
.topbar h1 { font-size: 22px; margin: 0; }
.user-chip { font-size: 13px; color: var(--muted); display: flex; align-items: center; gap: 10px; }
.user-chip button { background: none; border: 1px solid var(--border); border-radius: 6px; padding: 6px 12px; cursor: pointer; color: var(--muted); font-size: 12px; }

.menu-toggle { display: none; background: none; border: none; font-size: 22px; cursor: pointer; }

/* ---------- Cards / grid ---------- */
.card { background: var(--card); border-radius: var(--radius); padding: 20px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); margin-bottom: 20px; }
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 16px; margin-bottom: 24px; }
.stat-card { background: var(--card); border-radius: var(--radius); padding: 18px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); }
.stat-card .label { font-size: 12px; color: var(--muted); text-transform: uppercase; letter-spacing: 0.5px; margin-bottom: 6px; }
.stat-card .value { font-size: 26px; font-weight: 700; }
.stat-card .value.brand { color: var(--brand); }

/* ---------- Buttons ---------- */
.btn { display: inline-flex; align-items: center; gap: 6px; padding: 9px 16px; border-radius: 7px; border: none; background: var(--brand); color: #fff; font-size: 14px; cursor: pointer; font-weight: 600; }
.btn:hover { background: var(--brand-dark); }
.btn.secondary { background: #fff; color: var(--ink); border: 1px solid var(--border); }
.btn.secondary:hover { background: #f0f1f3; }
.btn.small { padding: 6px 12px; font-size: 12.5px; }
.btn.danger { background: var(--danger-ink); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* ---------- Forms ---------- */
label { display: block; font-size: 13px; font-weight: 600; margin-bottom: 6px; color: var(--muted); }
input, select, textarea {
  width: 100%; padding: 9px 12px; border: 1px solid var(--border); border-radius: 7px;
  font-size: 14px; font-family: inherit; margin-bottom: 14px; background: #fff; color: var(--ink);
}
input:focus, select:focus, textarea:focus { outline: none; border-color: var(--brand); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.checkbox-row { display: flex; align-items: center; gap: 8px; margin-bottom: 14px; }
.checkbox-row input { width: auto; margin: 0; }

/* ---------- Table ---------- */
table.data { width: 100%; border-collapse: collapse; background: var(--card); border-radius: var(--radius); overflow: hidden; }
table.data th { text-align: left; background: #fafbfc; padding: 12px 14px; font-size: 12px; text-transform: uppercase; color: var(--muted); border-bottom: 1px solid var(--border); }
table.data td { padding: 12px 14px; border-bottom: 1px solid var(--border); font-size: 14px; }
table.data tr:last-child td { border-bottom: none; }
table.data tr:hover { background: #fafbfc; }
.table-wrap { overflow-x: auto; }

/* ---------- Badges ---------- */
.badge { display: inline-block; padding: 3px 10px; border-radius: 12px; font-size: 11.5px; font-weight: 600; }
.badge-Paid, .badge-Accepted, .badge-Active { background: var(--success-bg); color: var(--success-ink); }
.badge-Unpaid, .badge-Overdue, .badge-Rejected { background: var(--danger-bg); color: var(--danger-ink); }
.badge-Partial, .badge-Draft, .badge-Sent { background: var(--warn-bg); color: var(--warn-ink); }
.badge-Void { background: #e4e7eb; color: #52606d; }

/* ---------- Modal ---------- */
.modal-overlay { position: fixed; inset: 0; background: rgba(31,41,51,0.5); display: flex; align-items: flex-start; justify-content: center; padding: 40px 16px; z-index: 100; overflow-y: auto; }
.modal { background: #fff; border-radius: var(--radius); padding: 24px; width: 100%; max-width: 560px; }
.modal h2 { margin-top: 0; font-size: 18px; }
.modal-actions { display: flex; justify-content: flex-end; gap: 10px; margin-top: 16px; }

/* ---------- Misc ---------- */
.muted { color: var(--muted); font-size: 13px; }
.empty-state { text-align: center; padding: 60px 20px; color: var(--muted); }
.error-banner { background: var(--danger-bg); color: var(--danger-ink); padding: 10px 14px; border-radius: 7px; font-size: 13px; margin-bottom: 14px; }
.success-banner { background: var(--success-bg); color: var(--success-ink); padding: 10px 14px; border-radius: 7px; font-size: 13px; margin-bottom: 14px; }
.item-row { display: grid; grid-template-columns: 3fr 1fr 1fr 1fr auto; gap: 8px; align-items: center; margin-bottom: 8px; }
.item-row input { margin-bottom: 0; }
.totals-box { margin-left: auto; width: 260px; }
.totals-box .row { display: flex; justify-content: space-between; padding: 6px 0; font-size: 14px; }
.totals-box .row.grand { font-weight: 700; font-size: 17px; border-top: 2px solid var(--ink); color: var(--brand); }

/* ---------- Auth page ---------- */
.auth-wrap { min-height: 100vh; display: flex; align-items: center; justify-content: center; background: linear-gradient(135deg, #1f2933, #3b4754); padding: 20px; }
.auth-card { background: #fff; border-radius: 14px; padding: 36px 32px; width: 100%; max-width: 400px; box-shadow: 0 10px 40px rgba(0,0,0,0.3); }
.auth-card h1 { font-size: 20px; margin: 0 0 4px 0; }
.auth-card .brand-mark { color: var(--brand); }
.auth-card p.subtitle { color: var(--muted); font-size: 13px; margin-bottom: 24px; }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); }
  .main { margin-left: 0; padding: 16px; }
  .menu-toggle { display: block; }
  .form-row { grid-template-columns: 1fr; }
  .item-row { grid-template-columns: 1fr; }
  table.data { font-size: 13px; }
}