*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    :root {
      --bg-sidebar: #16213e; --bg-main: #f0f2f7; --bg-card: #ffffff;
      --bg-topbar: #0f3460; --accent: #e94560; --accent-hover: #c73652;
      --accent-blue: #1a73e8; --text-primary: #1a1a2e; --text-secondary: #64748b;
      --text-sidebar: #a8b4cc; --border: #e2e8f0; --border-dark: #2a3f5f;
      --success: #10b981; --error: #ef4444; --warning: #f59e0b;
      --font: 'IBM Plex Sans KR', sans-serif; --mono: 'IBM Plex Mono', monospace;
      --sidebar-w: 220px; --topbar-h: 52px; --radius: 8px;
      --shadow: 0 1px 3px rgba(0,0,0,0.08);
    }
    body { font-family: var(--font); background: var(--bg-main); color: var(--text-primary); font-size: 14px; line-height: 1.5; -webkit-font-smoothing: antialiased; }
    button { cursor: pointer; font-family: var(--font); }
    input, textarea, select { font-family: var(--font); }

    /* Layout */
    #app { min-height: 100vh; }
    #topnav {
      position: fixed; top: 0; left: 0; right: 0; height: var(--topbar-h);
      background: var(--bg-sidebar); display: flex; align-items: center; z-index: 200;
      border-bottom: 1px solid var(--border-dark); box-shadow: 0 1px 6px rgba(0,0,0,0.15);
    }
    #topnav-logo { padding: 0 16px; border-right: 1px solid var(--border-dark); display: flex; align-items: center; gap: 9px; height: 100%; flex-shrink: 0; }
    #topnav-logo .icon { width: 30px; height: 30px; background: var(--accent); border-radius: 8px; display: flex; align-items: center; justify-content: center; font-size: 15px; flex-shrink: 0; }
    #topnav-logo .title { color: white; font-weight: 700; font-size: 13px; line-height: 1.3; }
    #topnav-logo .sub { color: #5a6a88; font-size: 10px; }
    #topnav-menu { display: flex; align-items: center; height: 100%; flex: 1; overflow: visible; padding: 0 4px; }
    .nav-item {
      display: flex; align-items: center; gap: 7px; height: 100%;
      padding: 0 13px; border: none; cursor: pointer; white-space: nowrap;
      font-family: var(--font); font-size: 13px; color: var(--text-sidebar);
      background: transparent; border-bottom: 2px solid transparent;
      text-align: left; transition: all 0.15s;
    }
    .nav-item:hover { background: rgba(255,255,255,0.06); color: white; }
    .nav-item.active { background: rgba(233,69,96,0.16); color: white; font-weight: 500; border-bottom-color: var(--accent); }
    .nav-item .nav-icon { font-size: 14px; }
    .nav-item .nav-caret { font-size: 9px; margin-left: 2px; color: #5a6a88; transition: transform 0.15s; }
    .nav-item.active .nav-caret { color: rgba(255,255,255,0.6); }
    .nav-group-wrap { position: relative; height: 100%; }
    .nav-dropdown {
      position: absolute; top: 100%; left: 0; min-width: 230px;
      background: white; border-radius: 0 0 10px 10px; box-shadow: 0 8px 24px rgba(0,0,0,0.18);
      padding: 6px; z-index: 300; display: none;
    }
    .nav-dropdown.open { display: block; }
    .nav-dropdown-item {
      display: flex; align-items: center; gap: 9px; width: 100%;
      padding: 8px 12px; border-radius: 7px; border: none; cursor: pointer;
      font-family: var(--font); font-size: 13px; color: var(--text-primary);
      background: transparent; text-align: left; margin-bottom: 1px;
    }
    .nav-dropdown-item:hover { background: #f1f5f9; }
    .nav-dropdown-item.active { background: rgba(233,69,96,0.1); color: var(--accent); font-weight: 500; }
    .nav-dropdown-item .nav-icon { font-size: 13px; }
    .nav-dropdown-subhead {
      font-size: 10px; font-weight: 700; color: var(--text-secondary); letter-spacing: 0.06em;
      text-transform: uppercase; padding: 8px 12px 4px; margin-top: 2px;
      border-top: 1px solid var(--border);
    }
    .nav-dropdown-subhead:first-child { border-top: none; margin-top: 0; padding-top: 4px; }
    #main { display: flex; flex-direction: column; min-height: 100vh; padding-top: var(--topbar-h); }
    #topnav-user { display: flex; align-items: center; gap: 14px; padding: 0 20px; flex-shrink: 0; height: 100%; }
    #topnav-user .welcome { color: #8faec8; font-size: 13px; white-space: nowrap; }
    #topnav-user .welcome strong { color: white; }
    #btn-logout { background: var(--accent); color: white; border: none; border-radius: 6px; padding: 6px 14px; font-size: 12px; font-weight: 500; }
    #btn-logout:hover { background: var(--accent-hover); }
    #content { flex: 1; padding: 28px 32px; }

    /* Login */
    #login-screen {
      min-height: 100vh; background: linear-gradient(135deg, #0f3460 0%, #16213e 60%, #1a1a2e 100%);
      display: flex; align-items: center; justify-content: center;
    }
    #login-box { width: 380px; }
    #login-logo { text-align: center; margin-bottom: 36px; display: flex; align-items: center; justify-content: center; gap: 10px; }
    #login-logo .icon { width: 42px; height: 42px; background: var(--accent); border-radius: 10px; display: flex; align-items: center; justify-content: center; font-size: 22px; }
    #login-logo .t1 { color: white; font-weight: 700; font-size: 20px; }
    #login-logo .t2 { color: #8899bb; font-size: 12px; }
    #login-card { background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.1); border-radius: 16px; padding: 36px 32px; backdrop-filter: blur(10px); }
    #login-card h2 { color: white; font-size: 18px; font-weight: 600; margin-bottom: 24px; }
    #login-hint { margin-top: 18px; padding: 10px 14px; background: rgba(255,255,255,0.04); border-radius: 8px; color: #6b7a99; font-size: 12px; }

    /* Common */
    .page-header { margin-bottom: 24px; display: flex; justify-content: space-between; align-items: flex-start; }
    .page-title { font-size: 22px; font-weight: 600; }
    .page-desc { font-size: 13px; color: var(--text-secondary); margin-top: 4px; }
    .card { background: var(--bg-card); border-radius: var(--radius); border: 1px solid var(--border); box-shadow: var(--shadow); }
    .btn { display: inline-flex; align-items: center; gap: 6px; padding: 8px 16px; border-radius: var(--radius); font-size: 13px; font-weight: 500; border: none; transition: all 0.15s; white-space: nowrap; cursor: pointer; font-family: var(--font); }
    .btn-primary { background: var(--accent); color: white; }
    .btn-primary:hover { background: var(--accent-hover); }
    .btn-secondary { background: white; color: var(--text-primary); border: 1px solid var(--border); }
    .btn-secondary:hover { background: #f8fafc; }
    .btn-blue { background: var(--accent-blue); color: white; }
    .btn-blue:hover { background: #1557b0; }
    .btn-danger { background: var(--error); color: white; }
    .btn-danger:hover { background: #dc2626; }
    .btn-sm { padding: 5px 10px; font-size: 12px; }
    .form-group { display: flex; flex-direction: column; gap: 5px; margin-bottom: 14px; }
    .form-label { font-size: 11px; font-weight: 600; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.05em; }
    .form-input { padding: 9px 12px; border-radius: var(--radius); border: 1px solid var(--border); font-size: 14px; transition: border-color 0.15s; outline: none; width: 100%; background: white; font-family: var(--font); }
    .form-input:focus { border-color: var(--accent-blue); box-shadow: 0 0 0 3px rgba(26,115,232,0.1); }
    .form-input::placeholder { color: #cbd5e1; }
    .form-hint { font-size: 11px; color: var(--text-secondary); }
    .form-input.dark { background: rgba(255,255,255,0.07); border-color: rgba(255,255,255,0.15); color: white; }
    .form-label.dark { color: #8899bb; }
    .error-box { background: #fee2e2; color: #991b1b; padding: 10px 14px; border-radius: 8px; font-size: 13px; margin-bottom: 14px; }
    .error-box.dark { background: rgba(239,68,68,0.15); border: 1px solid rgba(239,68,68,0.3); color: #fca5a5; }
    .badge { display: inline-flex; align-items: center; padding: 2px 8px; border-radius: 999px; font-size: 11px; font-weight: 500; }
    .badge-success { background: #d1fae5; color: #065f46; }
    .badge-error { background: #fee2e2; color: #991b1b; }
    .badge-info { background: #dbeafe; color: #1e40af; }
    .badge-warning { background: #fef3c7; color: #92400e; }
    .badge-danger { background: #fee2e2; color: #991b1b; }
    .hot-grid-wrap .handsontable td.hot-cell-error,
    .hot-grid-wrap .handsontable td.area.hot-cell-error,
    .hot-grid-wrap .handsontable td.current.hot-cell-error { background: #fef2f2 !important; color: #991b1b !important; box-shadow: inset 0 0 0 1px #fca5a5; }
    .hot-grid-wrap .handsontable .wtHolder { background: white; }
    .tag { display: inline-flex; align-items: center; padding: 2px 8px; background: #e0f2fe; color: #0369a1; border-radius: 4px; font-size: 12px; font-weight: 500; }
    .mono { font-family: var(--mono); }
    .table { width: 100%; border-collapse: collapse; }
    .table th { font-size: 11px; font-weight: 600; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.05em; padding: 10px 16px; border-bottom: 1px solid var(--border); text-align: left; background: #f8fafc; }
    .table td { padding: 12px 16px; border-bottom: 1px solid var(--border); font-size: 13px; }
    .table tr:last-child td { border-bottom: none; }
    .table tr:hover td { background: #fafbfc; }
    .empty-state { text-align: center; padding: 48px 24px; color: var(--text-secondary); }
    .empty-icon { font-size: 40px; margin-bottom: 12px; }
    .empty-title { font-size: 15px; font-weight: 500; color: var(--text-primary); margin-bottom: 6px; }
    .empty-desc { font-size: 13px; margin-bottom: 20px; }
    .code-block { background: #1e293b; color: #e2e8f0; border-radius: var(--radius); padding: 14px; font-family: var(--mono); font-size: 12px; overflow: auto; max-height: 380px; line-height: 1.6; white-space: pre; }
    .grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
    .grid4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
    .flex-row { display: flex; gap: 8px; align-items: center; }
    .flex-col { display: flex; flex-direction: column; gap: 16px; }

    /* Modal */
    .modal-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.45); display: flex; align-items: center; justify-content: center; z-index: 1000; backdrop-filter: blur(2px); animation: fadeIn 0.15s ease; }
    .modal { background: white; border-radius: 12px; width: 500px; max-width: 95vw; max-height: 85vh; overflow-y: auto; box-shadow: 0 20px 40px rgba(0,0,0,0.15); animation: slideUp 0.2s ease; }
    .modal-header { display: flex; align-items: center; justify-content: space-between; padding: 20px 24px 0; margin-bottom: 18px; }
    .modal-title { font-size: 16px; font-weight: 600; }
    .modal-body { padding: 0 24px; }
    .modal-footer { display: flex; justify-content: flex-end; gap: 8px; padding: 20px 24px; }
    .btn-close { background: none; border: 1px solid var(--border); border-radius: 6px; padding: 4px 8px; color: var(--text-secondary); font-size: 14px; }
    .btn-close:hover { background: #f8fafc; }
    @keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
    @keyframes slideUp { from { opacity: 0; transform: translateY(14px); } to { opacity: 1; transform: translateY(0); } }

    /* Scrollbar */
    ::-webkit-scrollbar { width: 6px; height: 6px; }
    ::-webkit-scrollbar-thumb { background: #c1c9d4; border-radius: 3px; }

    /* Method colors */
    .m-GET { color: #0f9d58; } .m-POST { color: #1a73e8; } .m-PUT { color: #f4b400; } .m-DELETE { color: #e94560; } .m-PATCH { color: #9b59b6; }

    /* Loading */
    #loading-screen { min-height: 100vh; display: flex; align-items: center; justify-content: center; background: var(--bg-main); color: var(--text-secondary); flex-direction: column; gap: 12px; }

@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }