minor fixes

1-js/02-first-steps/04-variables/2-declare-variables/solution.md

@@ -1,4 +1,4 @@
-First, the variable for the name of our planet.
+## The variable for our planet
 
 That's simple:
 
@@ -8,7 +8,7 @@ let ourPlanetName = "Earth";
 
 Note, we could use a shorter name `planet`, but it might be not obvious what planet it refers to. It's nice to be more verbose. At least until the variable isNotTooLong.
 
-Second, the name of the current visitor:
+## The name of the current visitor
 
 ```js
 let currentUserName = "John";

1-js/02-first-steps/04-variables/3-uppercast-constant/solution.md

@@ -2,4 +2,4 @@ We generally use upper case for constants that are "hard-coded". Or, in other wo
 
 In this code, `birthday` is exactly like that. So we could use the upper case for it.
 
-In contrast, `age` is evaluated in run-time. Today we have one age, a year after we'll have another one. It is constant in a sense that it does not change through the code execution. But it is a bit "less of a constant" than `birthday`, it is calculated, so we should keep the lower case for it.
+In contrast, `age` is evaluated in run-time. Today we have one age, a year after we'll have another one. It is constant in a sense that it does not change through the code execution. But it is a bit "less of a constant" than `birthday`: it is calculated, so we should keep the lower case for it.

1-js/02-first-steps/04-variables/article.md

@@ -323,7 +323,7 @@ Modern JavaScript minifiers and browsers optimize code well enough, so it won't
 
 We can declare variables to store data by using the `var`, `let`, or `const` keywords.
 
-- `let` -- is a modern variable declaration. The code must be in strict mode to use `let` in Chrome (V8).
+- `let` -- is a modern variable declaration.
 - `var` -- is an old-school variable declaration. Normally we don't use it at all, but we'll cover subtle differences from `let` in the chapter <info:var>, just in case you need them.
 - `const` -- is like `let`, but the value of the variable can't be changed.