/* =====================================================================
   ISP Billing System — Base Stylesheet
   Design language: "network operations" — slate/ink sidebar, signal-teal
   accent, mono type for technical data (IPs, account numbers, speeds).
   ===================================================================== */

:root {
  /* Palette */
  --color-ink: #0B1220;
  --color-slate-900: #111C2E;
  --color-slate-800: #1B2740;
  --color-slate-700: #2A3852;
  --color-slate-200: #E4E9F2;
  --color-bg: #F5F7FB;
  --color-surface: #FFFFFF;
  --color-border: #E2E6EF;
  --color-text: #16213A;
  --color-text-muted: #6B7690;
  --color-signal: #12B3A6;      /* primary accent: connectivity teal */
  --color-signal-dark: #0D8F85;
  --color-signal-soft: #E4F8F6;
  --color-amber: #E0A62B;
  --color-red: #D64545;
  --color-green: #2E9E5B;

  /* Type */
  --font-ui: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'SFMono-Regular', Consolas, monospace;

  /* Layout */
  --sidebar-width: 250px;
  --topbar-height: 64px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --shadow-card: 0 1px 2px rgba(16, 24, 40, 0.06), 0 1px 3px rgba(16, 24, 40, 0.08);
}

[data-theme="dark"] {
  --color-bg: #0B1220;
  --color-surface: #131E33;
  --color-border: #24304A;
  --color-text: #E9EDF6;
  --color-text-muted: #8B95AF;
  --color-signal-soft: #10262A;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-ui);
  font-size: 14px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-signal-dark); text-decoration: none; }
a:hover { text-decoration: underline; }

.mono { font-family: var(--font-mono); letter-spacing: -0.01em; }

/* ---------------------------------------------------------------------
   App shell
   --------------------------------------------------------------------- */

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

.sidebar {
  width: var(--sidebar-width);
  background: var(--color-ink);
  color: var(--color-slate-200);
  flex-shrink: 0;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  display: flex;
  flex-direction: column;
  transition: transform 0.2s ease;
  z-index: 40;
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 18px 20px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.sidebar-brand .mark {
  width: 28px; height: 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--color-signal), #1FD6C4);
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; color: var(--color-ink); font-size: 13px;
}

.sidebar-brand .name { font-weight: 600; font-size: 15px; color: #fff; }

.sidebar-nav { flex: 1; overflow-y: auto; padding: 12px 10px; }

.sidebar-section {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: rgba(228,233,242,0.4);
  padding: 14px 10px 6px;
}

.sidebar-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 10px;
  border-radius: var(--radius-sm);
  color: rgba(228,233,242,0.8);
  font-size: 13.5px;
  font-weight: 500;
  margin-bottom: 2px;
}

.sidebar-link:hover { background: rgba(255,255,255,0.06); text-decoration: none; color: #fff; }
.sidebar-link.active { background: var(--color-signal); color: var(--color-ink); }
.sidebar-link i { width: 18px; text-align: center; opacity: 0.9; }

.sidebar-foot {
  padding: 14px 16px;
  border-top: 1px solid rgba(255,255,255,0.08);
  font-size: 12px;
  color: rgba(228,233,242,0.5);
}

.main {
  margin-left: var(--sidebar-width);
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

/* Topbar */
.topbar {
  height: var(--topbar-height);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 22px;
  position: sticky;
  top: 0;
  z-index: 30;
}

.topbar-title { font-weight: 600; font-size: 16px; }
.topbar-actions { display: flex; align-items: center; gap: 14px; }

.icon-btn {
  width: 36px; height: 36px;
  display: flex; align-items: center; justify-content: center;
  border-radius: 50%;
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text-muted);
  cursor: pointer;
  position: relative;
}
.icon-btn:hover { background: var(--color-bg); }

.badge-dot {
  position: absolute; top: 6px; right: 7px;
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--color-red);
  border: 1.5px solid var(--color-surface);
}

.user-chip {
  display: flex; align-items: center; gap: 8px;
  cursor: pointer;
}
.user-avatar {
  width: 34px; height: 34px; border-radius: 50%;
  background: var(--color-signal-soft);
  color: var(--color-signal-dark);
  display: flex; align-items: center; justify-content: center;
  font-weight: 600; font-size: 13px;
}
.user-meta .name { font-size: 13px; font-weight: 600; line-height: 1.2; }
.user-meta .role { font-size: 11.5px; color: var(--color-text-muted); }

.content { padding: 24px; }

/* ---------------------------------------------------------------------
   Cards, buttons, forms, tables — shared components
   --------------------------------------------------------------------- */

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
}

.card-body { padding: 18px 20px; }
.card-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--color-border);
  font-weight: 600;
  font-size: 14.5px;
}

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  padding: 9px 16px;
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
  transition: filter 0.15s ease, background 0.15s ease;
}
.btn:disabled { opacity: 0.6; cursor: not-allowed; }
.btn-primary { background: var(--color-signal); color: var(--color-ink); }
.btn-primary:hover { filter: brightness(0.95); }
.btn-outline { background: transparent; border-color: var(--color-border); color: var(--color-text); }
.btn-outline:hover { background: var(--color-bg); }
.btn-danger { background: var(--color-red); color: #fff; }
.btn-block { width: 100%; }

.form-group { margin-bottom: 16px; }
.form-label { display: block; font-size: 13px; font-weight: 600; margin-bottom: 6px; color: var(--color-text); }
.form-control {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: 13.5px;
  font-family: var(--font-ui);
}
.form-control:focus {
  outline: none;
  border-color: var(--color-signal);
  box-shadow: 0 0 0 3px var(--color-signal-soft);
}
.form-error { color: var(--color-red); font-size: 12.5px; margin-top: 5px; display: none; }
.form-hint { color: var(--color-text-muted); font-size: 12px; margin-top: 5px; }

.alert {
  padding: 12px 14px;
  border-radius: var(--radius-sm);
  font-size: 13.5px;
  margin-bottom: 16px;
  border: 1px solid transparent;
}
.alert-error { background: #FDEDED; border-color: #F6C7C7; color: #9A2E2E; }
.alert-success { background: #E8F7EE; border-color: #BFE7CD; color: #1E7A46; }

.badge {
  display: inline-flex; align-items: center;
  padding: 3px 9px;
  border-radius: 999px;
  font-size: 11.5px;
  font-weight: 600;
  text-transform: capitalize;
}
.badge-active { background: #E8F7EE; color: var(--color-green); }
.badge-suspended { background: #FDF3E3; color: var(--color-amber); }
.badge-expired { background: #FDEDED; color: var(--color-red); }
.badge-pending { background: #EEF0F6; color: var(--color-text-muted); }

table.data-table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
table.data-table th {
  text-align: left; padding: 10px 14px;
  background: var(--color-bg);
  color: var(--color-text-muted);
  font-weight: 600; font-size: 12px; text-transform: uppercase; letter-spacing: 0.03em;
  border-bottom: 1px solid var(--color-border);
}
table.data-table td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--color-border);
}
table.data-table tr:hover td { background: var(--color-bg); }

@media (max-width: 960px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); }
  .main { margin-left: 0; }
}

:focus-visible { outline: 2px solid var(--color-signal); outline-offset: 2px; }

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}