:root {
            --primary: #2563eb;
            --secondary: #7c3aed;
            --accent: #10b981;
            --text-gradient: linear-gradient(to right, #2563eb, #7c3aed, #db2777);
            --bg-gradient: linear-gradient(135deg, #f0f4f8 0%, #e2e8f0 100%);
            --glass-bg: rgba(255, 255, 255, 0.95);
            --glass-border: rgba(255, 255, 255, 0.8);
            --card-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.1);
        }

        [data-theme="dark"] {
            --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
            --glass-bg: rgba(30, 41, 59, 0.98);
            --glass-border: rgba(255, 255, 255, 0.05);
            --text-main: #f8fafc;
            --text-dim: #94a3b8;
        }

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

        body {
            font-family: 'Inter', sans-serif;
            background: var(--bg-gradient);
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 15px;
            color: #1e293b;
            overflow: hidden;
        }

        body[data-theme="dark"] { color: var(--text-main); }

        .login-card {
            background: var(--glass-bg);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border: 1px solid var(--glass-border);
            border-radius: 28px;
            box-shadow: var(--card-shadow);
            width: 100%;
            max-width: 440px;
            padding: 40px 30px;
            text-align: center;
            position: relative;
            overflow: hidden;
            animation: cardEntrance 0.8s cubic-bezier(0.16, 1, 0.3, 1);
        }

        @keyframes cardEntrance {
            from { opacity: 0; transform: scale(0.9) translateY(20px); }
            to { opacity: 1; transform: scale(1) translateY(0); }
        }

        .content-wrap { position: relative; z-index: 1; }

        .logo-box { margin-bottom: 30px; }
        .logo-box img { height: 90px; width: auto; }

        h1 {
            font-size: 1.85rem;
            font-weight: 800;
            background: var(--text-gradient);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            margin-bottom: 15px;
            line-height: 1.1;
        }

        .desc { font-size: 0.95rem; color: #475569; margin-bottom: 25px; line-height: 1.6; }

        .google-btn {
            background: #ffffff;
            color: #1e293b;
            border: 1px solid #e2e8f0;
            padding: 14px 24px;
            border-radius: 16px;
            font-size: 1rem;
            font-weight: 700;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 12px;
            cursor: pointer;
            transition: all 0.3s;
            width: 100%;
            text-decoration: none;
            box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
        }

        .google-btn:hover {
            background: #f8fafc;
            border-color: var(--primary);
            transform: translateY(-2px);
            box-shadow: 0 10px 15px -3px rgba(37, 99, 235, 0.1);
        }

        .footer-note { margin-top: 25px; font-size: 0.75rem; color: #94a3b8; }

        .referral-badge {
            background: #ecfdf5;
            border: 1px solid #10b981;
            color: #065f46;
            padding: 10px 14px;
            border-radius: 14px;
            font-size: 0.85rem;
            font-weight: 500;
            display: flex;
            align-items: center;
            gap: 8px;
            margin-bottom: 18px;
            text-align: left;
            animation: fadeIn 0.3s ease;
        }

        [data-theme="dark"] .referral-badge {
            background: rgba(16, 185, 129, 0.15);
            border-color: rgba(16, 185, 129, 0.3);
            color: #6ee7b7;
        }

        .referral-box {
            margin-bottom: 18px;
            text-align: left;
        }

        .referral-toggle {
            font-size: 0.85rem;
            color: var(--primary);
            cursor: pointer;
            font-weight: 600;
            display: inline-flex;
            align-items: center;
            gap: 6px;
            user-select: none;
            transition: color 0.2s;
        }

        .referral-toggle:hover {
            color: var(--secondary);
            text-decoration: underline;
        }

        .referral-input {
            flex: 1;
            padding: 10px 14px;
            border-radius: 12px;
            border: 1px solid #cbd5e1;
            font-size: 0.9rem;
            text-transform: uppercase;
            font-weight: 600;
            outline: none;
            background: #ffffff;
            color: #1e293b;
            transition: border-color 0.2s;
        }

        .referral-input:focus {
            border-color: var(--primary);
        }

        [data-theme="dark"] .referral-input {
            background: rgba(30, 41, 59, 0.9);
            border-color: rgba(255, 255, 255, 0.15);
            color: #f8fafc;
        }

        .referral-apply-btn {
            background: var(--primary);
            color: #ffffff;
            border: none;
            border-radius: 12px;
            padding: 0 16px;
            font-size: 0.85rem;
            font-weight: 600;
            cursor: pointer;
            transition: background 0.2s;
        }

        .referral-apply-btn:hover {
            background: #1d4ed8;
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(-4px); }
            to { opacity: 1; transform: translateY(0); }
        }