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

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            background: linear-gradient(135deg, #0f172a 0%, #1e3a8a 50%, #0f172a 100%);
            transition: all 0.5s ease;
            position: relative;
            overflow: hidden;
        }

        body.light-on {
            background: linear-gradient(135deg, #1e3a8a 0%, #3b82f6 50%, #1e3a8a 100%);
        }

        /* تأثير الضوء */
        .light-effect {
            position: fixed;
            top: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 0;
            height: 0;
            background: radial-gradient(ellipse at top, rgba(59, 130, 246, 0) 0%, transparent 70%);
            opacity: 0;
            transition: all 0.5s ease;
            pointer-events: none;
            z-index: 1;
        }

        body.light-on .light-effect {
            width: 100vw;
            height: 100vh;
            opacity: 1;
            background: radial-gradient(ellipse at top, rgba(59, 130, 246, 0.3) 0%, transparent 70%);
        }

        

        /* الحاوية الرئيسية */
        .container {
            background: linear-gradient(135deg, rgba(30, 41, 59, 0.95), rgba(15, 23, 42, 0.95));
            padding: 40px;
            border-radius: 20px;
            box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
            width: 90%;
            max-width: 450px;
            position: relative;
            z-index: 10;
            backdrop-filter: blur(10px);
            border: 2px solid #334155;
            transition: all 0.5s ease;
        }

        body.light-on .container {
            background: linear-gradient(135deg, rgba(30, 41, 59, 0.98), rgba(15, 23, 42, 0.98));
            border: 2px solid rgba(59, 130, 246, 0.6);
            box-shadow: 0 0 60px rgba(59, 130, 246, 0.5),
                        0 0 100px rgba(59, 130, 246, 0.3),
                        0 20px 80px rgba(0, 0, 0, 0.8);
        }

        /* User Icon */
        .user-icon-container {
            display: flex;
            justify-content: center;
            margin-bottom: 20px;
        }

        .user-icon {
            width: 80px;
            height: 80px;
            background: linear-gradient(135deg, #3b82f6, #2563eb);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            box-shadow: 0 4px 20px rgba(59, 130, 246, 0.4);
            transition: all 0.5s ease;
        }

        body.light-on .user-icon {
            background: linear-gradient(135deg, #60a5fa, #3b82f6);
            box-shadow: 0 4px 30px rgba(59, 130, 246, 0.6),
                        0 0 40px rgba(59, 130, 246, 0.4);
            animation: pulse-icon 3s ease-in-out infinite;
        }

        @keyframes pulse-icon {
            0%, 100% {
                transform: scale(1);
                box-shadow: 0 4px 30px rgba(59, 130, 246, 0.6),
                            0 0 40px rgba(59, 130, 246, 0.4);
            }
            50% {
                transform: scale(1.05);
                box-shadow: 0 6px 40px rgba(59, 130, 246, 0.8),
                            0 0 60px rgba(59, 130, 246, 0.6);
            }
        }

        .user-icon svg {
            width: 40px;
            height: 40px;
            fill: white;
        }

        h2 {
            text-align: center;
            color: #60a5fa;
            margin-bottom: 10px;
            font-size: 28px;
            transition: all 0.5s ease;
        }

        body.light-on h2 {
            background: linear-gradient(to right, #60a5fa, #a78bfa, #22d3ee);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            animation: gradient-slide 3s ease infinite;
            background-size: 200% auto;
        }

        @keyframes gradient-slide {
            0%, 100% { background-position: 0% 50%; }
            50% { background-position: 100% 50%; }
        }

        .subtitle {
            text-align: center;
            color: #94a3b8;
            font-size: 14px;
            margin-bottom: 30px;
            transition: all 0.5s ease;
        }

        body.light-on .subtitle {
            color: #93c5fd;
        }

        .form-container {
            position: relative;
        }

        .form {
            display: none;
        }

        .form.active {
            display: block;
            animation: fadeIn 0.5s ease;
        }

        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .form-group {
            margin-bottom: 20px;
        }

        label {
            display: block;
            margin-bottom: 8px;
            color: #94a3b8;
            font-size: 14px;
            transition: all 0.5s ease;
        }

        body.light-on label {
            color: #93c5fd;
        }

        input {
            width: 100%;
            padding: 12px 15px;
            border: 1px solid #334155;
            border-radius: 10px;
            background: rgba(15, 23, 42, 0.6);
            color: #cbd5e1;
            font-size: 16px;
            transition: all 0.3s ease;
            outline: none;
        }

        body.light-on input {
            background: rgba(15, 23, 42, 0.4);
            color: #e2e8f0;
            border-color: rgba(59, 130, 246, 0.4);
        }

        input:focus {
            border-color: #3b82f6;
            background: rgba(30, 41, 59, 0.8);
        }

        body.light-on input:focus {
            border-color: #60a5fa;
            background: rgba(30, 41, 59, 0.6);
            box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
        }

        input::placeholder {
            color: #475569;
        }

        body.light-on input::placeholder {
            color: #64748b;
        }

        .btn {
            width: 100%;
            padding: 14px;
            border: none;
            border-radius: 10px;
            background: linear-gradient(135deg, #3b82f6, #2563eb);
            color: white;
            font-size: 16px;
            font-weight: bold;
            cursor: pointer;
            transition: all 0.3s ease;
            margin-top: 10px;
            box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
        }

        .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 25px rgba(59, 130, 246, 0.5);
            background: linear-gradient(135deg, #60a5fa, #3b82f6);
        }

        .btn:active {
            transform: translateY(0);
        }

        body.light-on .btn {
            background: linear-gradient(135deg, #2563eb, #1e40af);
            box-shadow: 0 8px 20px rgba(59, 130, 246, 0.4);
        }

        body.light-on .btn:hover {
            background: linear-gradient(135deg, #3b82f6, #2563eb);
            box-shadow: 0 10px 30px rgba(59, 130, 246, 0.6);
        }

        .toggle-text {
            text-align: center;
            margin-top: 20px;
            color: #64748b;
            font-size: 14px;
            transition: all 0.5s ease;
        }

        body.light-on .toggle-text {
            color: #93c5fd;
        }

        .toggle-link {
            color: #3b82f6;
            cursor: pointer;
            text-decoration: underline;
            font-weight: bold;
            transition: all 0.3s ease;
        }

        .toggle-link:hover {
            color: #60a5fa;
        }

        body.light-on .toggle-link {
            color: #60a5fa;
        }

        body.light-on .toggle-link:hover {
            color: #93c5fd;
        }

        .error-message {
            background: rgba(239, 68, 68, 0.1);
            border: 1px solid rgba(239, 68, 68, 0.3);
            color: #fca5a5;
            padding: 12px;
            border-radius: 8px;
            margin-bottom: 20px;
            display: none;
            font-size: 14px;
        }

        body.light-on .error-message {
            background: rgba(239, 68, 68, 0.15);
            color: #f87171;
            border-color: rgba(239, 68, 68, 0.4);
        }

        .error-message.show {
            display: block;
            animation: shake 0.5s ease;
        }

        @keyframes shake {
            0%, 100% { transform: translateX(0); }
            25% { transform: translateX(-10px); }
            75% { transform: translateX(10px); }
        }

        .success-message {
            background: rgba(34, 197, 94, 0.1);
            border: 1px solid rgba(34, 197, 94, 0.3);
            color: #86efac;
            padding: 12px;
            border-radius: 8px;
            margin-bottom: 20px;
            display: none;
            font-size: 14px;
        }

        body.light-on .success-message {
            background: rgba(34, 197, 94, 0.15);
            color: #4ade80;
            border-color: rgba(34, 197, 94, 0.4);
        }

        .success-message.show {
            display: block;
        }

        .row {
            display: flex;
            gap: 15px;
        }

        .row .form-group {
            flex: 1;
        }

        .loading {
            opacity: 0.6;
            pointer-events: none;
        }

        @media (max-width: 768px) {
            .container {
                padding: 30px 20px;
            }

            h2 {
                font-size: 24px;
            }

            .row {
                flex-direction: column;
                gap: 0;
            }

            .user-icon {
                width: 70px;
                height: 70px;
            }

            .user-icon svg {
                width: 35px;
                height: 35px;
            }
        }