Craft an eye-catching Black Friday promotional banner with a 16:9 aspect ratio that conveys urgency and excitement. The banner should feature the phrase 'BLACK FRIDAY' in a modern bold font, rendered in a vibrant orange color with a white outline to enhance its visibility against the dynamic background. Below this, the text '50% OFF' should be prominently displayed in a bold red, making it the focal point of the design. On either side of the main text, incorporate stylish analog countdown clocks in black and orange, designed to create a sense of urgency and encourage immediate action. The background should be filled with radial lines that radiate outward, transitioning from a deep orange at the center to a lighter shade towards the edges, enhancing the overall vibrancy and excitement of the banner. Ensure that the background remains transparent for easy integration into various media formats. The composition should be clean and modern, with a strong emphasis on the bold typography and countdown clocks, ensuring that the promotional message is clear and compelling to potential customers.