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

:root {
  --bg: #f0f2f5;
  --surface: #ffffff;
  --surface2: #e8ecf1;
  --accent: #0066cc;
  --accent2: #7928ca;
  --success: #00a843;
  --danger: #e53e3e;
  --warning: #dd8800;
  --text: #1a1a1a;
  --text2: #5a6577;
  --border: #d8dde6;
  --radius: 8px;
}

body {
  font-family: 'Segoe UI', 'Pretendard', sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
  overflow: hidden;
  height: 100vh;
}

/* === Layout === */
.app {
  display: grid;
  grid-template-columns: 320px 1fr 480px;
  grid-template-rows: 48px 1fr;
  height: 100vh;
  gap: 0;
}

/* Header */
.header {
  grid-column: 1 / -1;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 16px;
  gap: 16px;
}
.header h1 { font-size: 16px; color: var(--accent); font-weight: 600; }
.header .status { margin-left: auto; display: flex; gap: 16px; align-items: center; font-size: 12px; color: var(--text2); }
.header .status .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--success); display: inline-block; margin-right: 4px; }

/* Panels */
.panel { background: var(--surface); border-right: 1px solid var(--border); overflow-y: auto; }
.panel:last-child { border-right: none; }
.panel-header {
  padding: 12px 16px;
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--surface);
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Center panel */
.center { background: var(--bg); overflow-y: auto; padding: 16px; display: flex; flex-direction: column; gap: 12px; }

/* === Components === */

/* Card */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
}
.card-title {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 6px;
}

/* Form */
.form-row { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.form-row label { width: 90px; font-size: 12px; color: var(--text2); flex-shrink: 0; }
.form-row input, .form-row select {
  flex: 1;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 10px;
  border-radius: 4px;
  font-size: 13px;
  outline: none;
}
.form-row input:focus, .form-row select:focus { border-color: var(--accent); }

/* Buttons */
.btn {
  padding: 6px 14px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 12px;
  font-weight: 500;
  transition: opacity 0.2s;
}
.btn:hover { opacity: 0.85; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-success { background: var(--success); color: #fff; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-warning { background: var(--warning); color: #fff; }
.btn-secondary { background: var(--border); color: var(--text); }
.btn-sm { padding: 4px 10px; font-size: 11px; }
.btn-group { display: flex; gap: 4px; flex-wrap: wrap; margin-top: 8px; }

/* Table */
table { width: 100%; border-collapse: collapse; font-size: 12px; }
th, td { padding: 6px 10px; text-align: left; border-bottom: 1px solid var(--border); }
th { color: var(--text2); font-weight: 500; font-size: 11px; text-transform: uppercase; position: sticky; top: 0; background: var(--surface); }
tr:hover { background: rgba(0, 102, 204, 0.06); }
tr.selected { background: rgba(0, 102, 204, 0.12); }
.online-dot { width: 8px; height: 8px; border-radius: 50%; display: inline-block; }
.online-dot.on { background: var(--success); }
.online-dot.off { background: var(--danger); opacity: 0.5; }

/* User tree */
.user-list { padding: 0; }
.group-header {
  padding: 8px 16px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text2);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  border-bottom: 1px solid var(--border);
  user-select: none;
}
.group-header:hover { background: rgba(0,0,0,0.03); }
.group-header .arrow { transition: transform 0.2s; font-size: 10px; }
.group-header .arrow.open { transform: rotate(90deg); }
.group-header .count { color: var(--accent); margin-left: auto; font-size: 11px; }
.group-users { display: none; }
.group-users.open { display: block; }
.user-item {
  padding: 6px 16px 6px 32px;
  font-size: 12px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid var(--border);
}
.user-item:hover { background: rgba(0, 102, 204, 0.06); }
.user-item.selected { background: rgba(0, 102, 204, 0.1); border-left: 3px solid var(--accent); }
.user-item .uid { flex: 1; }
.user-item .expiry { color: var(--text2); font-size: 11px; }

/* Log */
.log-area {
  background: #f8f9fa;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 8px;
  font-family: 'Consolas', 'Courier New', monospace;
  font-size: 11px;
  line-height: 1.5;
  overflow-y: auto;
  flex: 1;
  min-height: 200px;
  max-height: 400px;
  color: var(--text2);
}
.log-area .error { color: var(--danger); }
.log-area .success { color: var(--success); }

/* Active clients table */
.active-table { font-size: 11px; width: 100%; table-layout: fixed; }
.active-table th, .active-table td { padding: 4px 6px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.active-table th { font-size: 11px; }
.profit-neg { color: #e53e3e !important; }
.profit-pos { color: #3b82f6 !important; }
.col-virtual { color: #5bc0de; }
.col-real { color: #d4a017; }

/* Tabs */
.tabs { display: flex; border-bottom: 1px solid var(--border); }
.tab {
  padding: 8px 16px;
  font-size: 12px;
  cursor: pointer;
  color: var(--text2);
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
}
.tab:hover { color: var(--text); }
.tab.active { color: var(--accent); border-bottom-color: var(--accent); }
.tab-content { display: none; }
.tab-content.active { display: block; }

/* Modal */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}
.modal {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  min-width: 400px;
  max-width: 500px;
}
.modal h3 { font-size: 15px; color: var(--accent); margin-bottom: 16px; }

/* Toast */
.toast {
  position: fixed;
  bottom: 20px;
  right: 20px;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 20px;
  font-size: 13px;
  z-index: 2000;
  animation: fadeIn 0.3s;
}
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* Login */
.login-screen {
  position: fixed;
  inset: 0;
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 5000;
}
.login-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  width: 360px;
  max-width: 90vw;
}
.login-box h2 { font-size: 18px; color: var(--accent); margin-bottom: 4px; }
.login-box p { font-size: 12px; color: var(--text2); margin-bottom: 20px; }
.login-remember { margin: 12px 0; font-size: 12px; color: var(--text2); }
.login-remember input { margin-right: 4px; }

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text2); }

/* Responsive */
@media (max-width: 1200px) {
  .app { grid-template-columns: 280px 1fr 420px; }
}

@media (max-width: 768px) {
  body { overflow: auto; height: auto; }
  .app {
    display: flex;
    flex-direction: column;
    height: auto;
    min-height: 100vh;
  }
  .header {
    flex-wrap: wrap;
    padding: 8px 12px;
    gap: 8px;
  }
  .header h1 { font-size: 14px; }
  .header .status { font-size: 11px; gap: 8px; }
  .panel {
    border-right: none;
    border-bottom: 1px solid var(--border);
    overflow-y: visible;
  }
  .center { padding: 8px; }
  .card { padding: 12px; }
  .form-row { flex-wrap: wrap; }
  .form-row label { width: 100%; margin-bottom: 2px; }
  .form-row input, .form-row select { width: 100%; }
  .btn-group { flex-wrap: wrap; }
  .modal { min-width: auto; max-width: 90vw; margin: 16px; padding: 16px; }
  .log-area { min-height: 150px; max-height: 300px; }
  .user-list { max-height: 300px; overflow-y: auto; }
  .active-table { font-size: 11px; }
  .active-table td { padding: 4px 6px; }
}

.active-group-header td {
  background: var(--card);
  cursor: pointer;
  font-weight: bold;
  font-size: 13px;
  padding: 6px 8px;
  user-select: none;
}
.active-group-header .arrow { font-size: 10px; display: inline-block; transition: transform 0.15s; }
.active-group-header .arrow.open { transform: rotate(90deg); }
.active-group-header .count { font-size: 11px; color: var(--text2); font-weight: normal; margin-left: 4px; }