/* =========================================
           1. CSS VARIABLES (THEME & TOKENS)
           ========================================= */
        :root {
            /* Colors */
            --bg: #000000;
            --surface: #1c1c1e;
            --surface-light: #2c2c2e;
            --surface-hover: #3a3a3c;
            
            --primary: #0A84FF;
            --success: #30D158;
            --danger: #FF453A;
            --warning: #FF9F0A;
            
            --text-main: #ffffff;
            --text-secondary: #8e8e93;
            --text-muted: #636366;
            
            --border: rgba(255, 255, 255, 0.1);
            --border-hover: rgba(255, 255, 255, 0.2);
            
            /* Typography */
            --font-sans: 'Inter', -apple-system, sans-serif;
            --font-mono: 'SF Mono', Consolas, monospace;
            
            /* Border Radius */
            --radius-sm: 8px;
            --radius-md: 14px;
            --radius-lg: 20px;
            --radius-xl: 28px;
            
            /* Shadows */
            --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.1);
            --shadow-lg: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
            
            /* Transitions */
            --transition: 0.2s ease-in-out;
        }

        /* =========================================
           2. RESET & BASE
           ========================================= */
        * { box-sizing: border-box; margin: 0; padding: 0; }
        body { 
            background-color: var(--bg); 
            color: var(--text-main); 
            font-family: var(--font-sans); 
            -webkit-font-smoothing: antialiased; 
            padding: 20px; 
            display: flex; 
            justify-content: center;
            line-height: 1.5;
        }
        .container { width: 100%; max-width: 1000px; animation: fadeIn 0.6s ease-out; }
        h1, h2, h3, h4 { color: var(--text-main); font-weight: 700; letter-spacing: -0.5px; margin-bottom: 15px; }
        p { color: var(--text-secondary); margin-bottom: 15px; font-size: 14px; }
        
        @keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

        /* =========================================
           3. LAYOUT & GRID
           ========================================= */
        .grid { display: grid; gap: 20px; margin-bottom: 30px; }
        .grid-2 { grid-template-columns: repeat(2, 1fr); }
        .grid-3 { grid-template-columns: repeat(3, 1fr); }
        .grid-4 { grid-template-columns: repeat(4, 1fr); }
        
        .flex { display: flex; gap: 12px; }
        .flex-col { flex-direction: column; }
        .items-center { align-items: center; }
        .justify-between { justify-content: space-between; }
        
        .section-divider { border-bottom: 1px solid var(--border); margin: 40px 0; }

        /* =========================================
           4. COMPONENTS
           ========================================= */
        
        /* Cards */
        .card { background: var(--surface); padding: 25px; border-radius: var(--radius-xl); border: 1px solid var(--border); box-shadow: var(--shadow-sm); }
        .card-stat { padding: 18px; border-radius: var(--radius-lg); }
        .card-stat .label { color: var(--text-secondary); font-size: 10px; font-weight: 700; text-transform: uppercase; margin-bottom: 4px; display: block; }
        .card-stat .value { font-size: 24px; font-weight: 700; }

        /* Buttons */
        .btn { padding: 12px 24px; border-radius: var(--radius-md); font-weight: 600; font-size: 14px; border: none; cursor: pointer; display: inline-flex; align-items: center; justify-content: center; gap: 8px; transition: var(--transition); text-decoration: none; }
        .btn:disabled { opacity: 0.5; cursor: not-allowed; }
        
        .btn-primary { background: var(--primary); color: white; }
        .btn-primary:hover:not(:disabled) { filter: brightness(1.1); }
        
        .btn-secondary { background: var(--surface-light); color: var(--text-main); border: 1px solid var(--border); }
        .btn-secondary:hover:not(:disabled) { background: var(--surface-hover); }
        
        .btn-danger { background: rgba(255, 69, 58, 0.15); color: var(--danger); border: 1px solid transparent; }
        .btn-danger:hover:not(:disabled) { background: rgba(255, 69, 58, 0.25); }
        
        .btn-outline { background: transparent; color: var(--text-main); border: 1px solid var(--border); }
        .btn-outline:hover:not(:disabled) { border-color: var(--primary); color: var(--primary); }

        /* Forms */
        .form-group { margin-bottom: 15px; display: flex; flex-direction: column; gap: 6px; }
        .form-label { font-size: 12px; font-weight: 600; color: var(--text-secondary); text-transform: uppercase; }
        
        .form-control { width: 100%; background: var(--surface-light); border: 1px solid var(--border); padding: 14px; border-radius: var(--radius-md); color: white; font-weight: 500; outline: none; transition: var(--transition); font-family: var(--font-sans); }
        .form-control:focus { border-color: var(--primary); box-shadow: 0 0 0 2px rgba(10, 132, 255, 0.2); }
        
        textarea.form-control { font-family: var(--font-mono); font-size: 13px; min-height: 120px; resize: vertical; }

        /* Alerts */
        .alert { padding: 16px 20px; border-radius: var(--radius-md); display: flex; align-items: center; justify-content: space-between; font-size: 14px; font-weight: 500; margin-bottom: 15px; border-left: 4px solid; }
        .alert-info { background: rgba(10, 132, 255, 0.1); color: var(--text-main); border-left-color: var(--primary); }
        .alert-success { background: rgba(48, 209, 88, 0.1); color: var(--text-main); border-left-color: var(--success); }
        .alert-danger { background: rgba(255, 69, 58, 0.1); color: var(--text-main); border-left-color: var(--danger); }
        .alert .close-btn { background: none; border: none; color: inherit; opacity: 0.6; cursor: pointer; padding: 4px; }
        .alert .close-btn:hover { opacity: 1; }

        /* Badges & Tags */
        .badge { padding: 5px 12px; border-radius: var(--radius-sm); font-size: 10px; font-weight: 800; text-transform: uppercase; display: inline-flex; align-items: center; gap: 4px; }
        .badge-primary { background: rgba(10, 132, 255, 0.15); color: var(--primary); }
        .badge-success { background: rgba(48, 209, 88, 0.15); color: var(--success); }
        .badge-danger { background: rgba(255, 69, 58, 0.15); color: var(--danger); }
        .badge-warning { background: rgba(255, 159, 10, 0.15); color: var(--warning); }
        
        .tag { background: var(--surface-light); color: var(--text-secondary); font-size: 10px; padding: 3px 8px; border-radius: 6px; font-weight: 600; text-transform: uppercase; border: 1px solid var(--border); }

        /* Tabs */
        .tabs-nav { display: flex; background: rgba(0,0,0,0.2); border-radius: 22px; padding: 4px; margin-bottom: 15px; border: 1px solid var(--border); }
        .tab-btn { flex: 1; padding: 12px; border: none; background: transparent; color: var(--text-secondary); font-weight: 600; font-size: 13px; cursor: pointer; border-radius: 18px; transition: var(--transition); }
        .tab-btn:hover { color: var(--text-main); }
        .tab-btn.active { background: var(--surface-light); color: white; box-shadow: var(--shadow-sm); }
        .tab-content { display: none; animation: fadeIn 0.3s ease; }
        .tab-content.active { display: block; }

        /* Modals */
        .modal-overlay { position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.7); backdrop-filter: blur(5px); z-index: 1000; display: flex; justify-content: center; align-items: center; opacity: 0; pointer-events: none; transition: var(--transition); }
        .modal-overlay.active { opacity: 1; pointer-events: auto; }
        .modal { background: var(--surface); width: 90%; max-width: 500px; border-radius: var(--radius-xl); border: 1px solid var(--border); padding: 30px; transform: scale(0.95) translateY(20px); transition: var(--transition); box-shadow: var(--shadow-lg); }
        .modal-overlay.active .modal { transform: scale(1) translateY(0); }
        .modal-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; }
        .modal-header h3 { margin: 0; }
        .modal-close { background: var(--surface-light); border: none; color: var(--text-secondary); width: 30px; height: 30px; border-radius: 50%; cursor: pointer; display: flex; align-items: center; justify-content: center; transition: var(--transition); }
        .modal-close:hover { background: var(--surface-hover); color: var(--text-main); }

        /* List Items (from Checker) */
        .list-item { background: rgba(255,255,255,0.02); border-radius: var(--radius-lg); padding: 15px 20px; margin-bottom: 10px; display: flex; justify-content: space-between; align-items: center; border: 1px solid var(--border); transition: var(--transition); }
        .list-item:hover { border-color: var(--border-hover); background: rgba(255,255,255,0.04); }
        .list-main { font-family: var(--font-mono); font-size: 14px; font-weight: 600; color: var(--text-main); margin-bottom: 6px; }

        /* Utilities */
        .text-primary { color: var(--primary); }
        .text-success { color: var(--success); }
        .text-danger { color: var(--danger); }
        .mt-20 { margin-top: 20px; }
        
        /* Responsive */
        @media (max-width: 768px) {
            .grid-4, .grid-3 { grid-template-columns: repeat(2, 1fr); }
            .flex-mobile-col { flex-direction: column; }
            .list-item { flex-direction: column; align-items: flex-start; gap: 15px; }
        }