:root {
            --primary: #2563eb;
            --primary-light: #3b82f6;
            --secondary: #8b5cf6;
            --bg: #f3f4f6;
            --text: #1f2937;
            --white: #ffffff;
        }

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

        body {
            font-family: Arial, sans-serif;
            background-color: var(--bg);
            color: var(--text);
            display: flex;
            align-items: center;
            justify-content: center;
            min-height: 100vh;
            padding: 1rem;
        }

        .gradient-border {
            padding: 2px;
            border-radius: .75rem;
            background: linear-gradient(to right, var(--primary), var(--secondary));
            animation: pulse 3s ease-in-out infinite;
        }

        @keyframes pulse {

            0%,
            100% {
                opacity: 1;
            }

            50% {
                opacity: .8;
            }
        }

        .form-container {
            background: var(--white);
            border-radius: .5rem;
            padding: 2rem;
            box-shadow: 0 8px 24px rgba(0, 0, 0, .1);
            width: 100%;
            max-width: 400px;
        }

        .form-header {
            text-align: center;
            margin-bottom: 1.5rem;
        }

        .form-header h1 {
            font-size: 2rem;
            font-weight: 800;
        }

        .form-header .highlight {
            color: var(--primary);
        }

        .form-header p {
            color: #6b7280;
            margin-top: .5rem;
        }

        .input-group {
            position: relative;
            margin-bottom: 1.25rem;
        }

        .input-group .icon {
            position: absolute;
            left: 1rem;
            top: 50%;
            transform: translateY(-50%);
            width: 1rem;
            height: 1rem;
            color: #6b7280;
        }

        .input-group input {
            width: 100%;
            padding: .75rem 1rem .75rem 2.5rem;
            border: 1px solid #d1d5db;
            border-radius: .375rem;
            background: var(--bg);
            font-size: 1rem;
            color: var(--text);
            transition: border-color .3s, box-shadow .3s;
        }

        .input-group input:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.4);
        }

        .is-invalid {
            border-color: #dc3545 !important;
        }

        .invalid-feedback {
            color: #dc3545;
            font-size: .875rem;
            margin-top: .25rem;
        }

        .btn {
            width: 100%;
            background: var(--primary);
            color: var(--white);
            padding: .75rem;
            border: none;
            border-radius: .375rem;
            font-size: 1rem;
            font-weight: 600;
            cursor: pointer;
            transition: background .3s;
        }

        .btn:hover {
            background: var(--primary-light);
        }

        .signin-text {
            text-align: center;
            font-size: .875rem;
            color: #6b7280;
            margin-top: 1.5rem;
        }

        .signin-text a {
            color: var(--primary);
            text-decoration: none;
            font-weight: 500;
            transition: text-decoration .3s;
        }

        .signin-text a:hover {
            text-decoration: underline;
        }