When we add something like color: green;, we're adding a declaration. Declarations are CSS, not HTML.
<body>
<h1 style="color: green;">Flowers by Ana</h1>
</body>
A declaration is made out of a CSS property, like color, and a value, like pink. The property always comes first.
<body>
<h1>Concerts near you</h1>
<h2 style="color: pink;">P!NK - Best of Tour</h2>
</body>
We add : in between the property and the value, and ; at the end of a declaration.
<body>
<h1 style="color: pink;">Flowers by Ana</h1>
</body>
We can add as many properties as we want as long as we end each one with a semicolon, ;.
<body>
<h1 style="color: pink; background-color: darkGreen;">Flowers by Ana</h1>
</body>