<!DOCTYPE html> <html lang="en"> <head> <title>Solar System: Document Object Model:30 Days Of JavaScript</title> <link href="https://fonts.googleapis.com/css?family=Montserrat:300,400,500,600,700&display=swap" rel="stylesheet"> </head> <body> <header> <h1>Calculate a weight of an object on a planet</h1> <input type="text" id="mass" placeholder="Mass in Kilogram" /> <select> <option value='none'>--select planet-- </option> </select> <button>Calculate weight</button> </header> <main> <div class="flex-container"> <div class="flex-item image"> <img src='./images/earth.png' class="planet-image" /> </div> <div class="flex-item description"></div> </div> </main> <script src="./scripts/main.js"></script> </body> </html>