:root {
  --black:   #1a1a1a;
  --mid:     #555;
  --light:   #f7f7f7;
  --border:  #e0e0e0;
  --white:   #fff;
  --green:   #155724;
  --green-bg:#d4edda;
  --blue:    #0c5460;
  --blue-bg: #d1ecf1;
  --yellow:  #856404;
  --yellow-bg:#fff3cd;
  --red:     #721c24;
  --red-bg:  #f8d7da;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-size: 14px;
  background: var(--white);
  color: var(--black);
}

/* ── Sidebar ── */
.sidebar {
  position: fixed;
  top: 0; left: 0;
  width: 220px;
  height: 100vh;
  background: var(--black);
  color: #fff;
  display: flex;
  flex-direction: column;
  z-index: 100;
}
.sidebar-logo {
  padding: 22px 24px 18px;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -.5px;
  color: #fff;
  text-decoration: none;
  border-bottom: 1px solid rgba(255,255,255,.12);
  cursor: pointer;
}
.sidebar-logo sup { font-size: 13px; vertical-align: super; }
.sidebar-nav { padding: 16px 0; flex: 1; overflow-y: auto; }
.nav-section {
  padding: 14px 24px 4px;
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: rgba(255,255,255,.35);
}
.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 24px;
  color: rgba(255,255,255,.7);
  cursor: pointer;
  font-size: 13.5px;
  transition: background .15s, color .15s;
  text-decoration: none;
}
.nav-item:hover  { color: #fff; background: rgba(255,255,255,.08); }
.nav-item.active { color: #fff; background: rgba(255,255,255,.12); }
.sidebar-footer {
  padding: 16px 24px;
  border-top: 1px solid rgba(255,255,255,.1);
  font-size: 12px;
}
.sidebar-footer button {
  background: none; border: none;
  color: rgba(255,255,255,.5);
  cursor: pointer; font-size: 12px; padding: 0;
}
.sidebar-footer button:hover { color: #fff; }

/* ── Main ── */
.main-content {
  margin-left: 220px;
  padding: 32px 36px;
  max-width: 1100px;
}
.page-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 28px;
}
.page-header h2 {
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -.3px;
}

/* ── Stat cards ── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-bottom: 32px;
}
.stat-card {
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 20px 22px;
}
.stat-label {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .8px;
  color: var(--mid);
  margin-bottom: 4px;
}
.stat-value {
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -.5px;
}
.stat-sub { font-size: 12px; color: var(--mid); margin-top: 2px; }

/* ── Tables ── */
.k2-table { width: 100%; border-collapse: collapse; }
.k2-table th {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .6px;
  color: var(--mid);
  font-weight: 500;
  padding: 0 12px 8px;
  border-bottom: 1px solid var(--border);
  text-align: left;
}
.k2-table td {
  padding: 10px 12px;
  border-bottom: 1px solid #f2f2f2;
  vertical-align: middle;
}
.k2-table tbody tr:hover { background: var(--light); }
.k2-table .right { text-align: right; }
.k2-table .muted { color: var(--mid); }
.k2-table .actions { text-align: right; white-space: nowrap; }

/* ── Buttons ── */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 7px 16px; font-size: 13px; font-weight: 500;
  border-radius: 4px; cursor: pointer; border: none;
  text-decoration: none; transition: background .15s;
}
.btn-primary { background: var(--black); color: #fff; }
.btn-primary:hover { background: #333; }
.btn-outline {
  background: #fff; color: var(--black);
  border: 1px solid var(--border);
}
.btn-outline:hover { border-color: var(--black); }
.btn-danger { background: #c00; color: #fff; }
.btn-danger:hover { background: #a00; }
.btn-sm { padding: 4px 10px; font-size: 12px; }
.btn-group { display: flex; gap: 8px; }

/* ── Forms ── */
.form-card {
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 28px;
  max-width: 580px;
}
.form-row { display: grid; gap: 16px; margin-bottom: 16px; }
.form-row.cols-2 { grid-template-columns: 1fr 1fr; }
.form-row.cols-3 { grid-template-columns: 1fr 1fr 1fr; }
.form-row.cols-1-2 { grid-template-columns: 1fr 2fr; }
.form-row.cols-3-1 { grid-template-columns: 3fr 1fr; }
.form-group { display: flex; flex-direction: column; gap: 4px; }
.form-label {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .5px;
  color: var(--mid);
  font-weight: 500;
}
.form-control, .form-select {
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 8px 10px;
  font-size: 14px;
  font-family: inherit;
  color: var(--black);
  background: #fff;
  width: 100%;
}
.form-control:focus, .form-select:focus {
  outline: none;
  border-color: var(--black);
}
.form-actions { display: flex; gap: 10px; margin-top: 24px; }

/* ── Status badges ── */
.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 3px;
  font-size: 11px;
  font-weight: 500;
  border: 1px solid transparent;
}
.badge-draft    { background: var(--yellow-bg); color: var(--yellow); border-color: #ffc107; }
.badge-sent     { background: var(--blue-bg);   color: var(--blue);   border-color: #bee5eb; }
.badge-paid     { background: var(--green-bg);  color: var(--green);  border-color: #c3e6cb; }
.badge-open     { background: var(--yellow-bg); color: var(--yellow); border-color: #ffc107; }
.badge-invoiced { background: var(--blue-bg);   color: var(--blue);   border-color: #bee5eb; }
.badge-internal { background: #f2f2f2; color: #888; }

/* ── Alerts ── */
.alert {
  padding: 10px 16px;
  border-radius: 4px;
  margin-bottom: 16px;
  font-size: 13.5px;
}
.alert-success { background: var(--green-bg);  color: var(--green); }
.alert-danger  { background: var(--red-bg);    color: var(--red); }
.alert-info    { background: var(--blue-bg);   color: var(--blue); }

/* ── Month nav ── */
.month-nav {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 20px;
}
.month-nav span {
  font-size: 16px;
  font-weight: 600;
  min-width: 160px;
  text-align: center;
}

/* ── Login ── */
.login-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  background: var(--light);
}
.login-box {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 40px;
  width: 340px;
}
.login-logo { font-size: 28px; font-weight: 700; letter-spacing: -.5px; margin-bottom: 4px; }
.login-logo sup { font-size: 16px; vertical-align: super; }
.login-sub { font-size: 13px; color: #777; margin-bottom: 28px; }

/* ── Misc ── */
.two-col { display: grid; grid-template-columns: 1.4fr 1fr; gap: 28px; }
.section-title {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: .5px;
  color: var(--mid);
  margin-bottom: 14px;
  font-weight: 600;
}
.empty-state {
  text-align: center;
  padding: 48px 0;
  color: #bbb;
}
.empty-state .icon { font-size: 32px; display: block; margin-bottom: 10px; }
.filter-tabs {
  display: flex;
  gap: 4px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 20px;
}
.filter-tab {
  padding: 6px 14px;
  font-size: 13px;
  cursor: pointer;
  border: none;
  background: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  color: var(--mid);
}
.filter-tab.active { border-bottom-color: var(--black); color: var(--black); font-weight: 600; }
.action-btn {
  background: none; border: none;
  color: #bbb; cursor: pointer;
  font-size: 14px; padding: 2px 4px;
  transition: color .15s;
}
.action-btn:hover { color: var(--black); }
.action-btn.danger:hover { color: #c00; }