style.css

body {
    width: 100%;
    height: 100vh;
    margin: 0;    /* by setting margin to 0, horizontal scroll-bar is removed. */
    background-color: #1b1b32;
    color: #f5f6f7;    /* text color */
    font-family: Tahoma;
    font-size: 16px
  }
  
  label {
    display: block;    /* make label elements appear on separate lines (label elements are inline by default). */
    margin: 0.5rem 0;    /* enables spacing between lines */
  }
  
  h1, p {
    margin: 1em auto;
    text-align: center;
  }
  
  form {
    margin: 0 auto;
    max-width: 500px;
    min-width: 300px;
    width: 60vw;
    padding-bottom: 2em;
  }
  
  fieldset {
    /* padding-top: 2rem;
    padding-bottom: 2rem;
    padding-left: 0;
    padding-right: 0; */
    padding: 2rem 0;
    border: none;    /* removes default border */
    border-bottom: 3px solid #3b3b4f;
  }
  
  /* This targets the last fieldset element and sets a change. */
  fieldset:last-of-type {border-bottom: none;}
  
  input, textarea, select {
    width: 100%;    /* makes label text appear above the form elements. */
    margin-top: 10px;
    margin-bottom: 0;
    margin-left: 0;
    margin-right: 0;
    min-height: 2em;
  }
  
  input, textarea {
    background-color: #0a0a23;
    border: 1px solid #0a0a23;
    color: #ffffff;
  }
  
  
  /* attribute selector: selects an element based on the given attribute value. */
  input[type="submit"] {
    display: block;
    width: 60%;
    margin: 1em auto;    /* aligns the button at the center */
    height: 2em;
    font-size: 1.1rem;
    background-color: #3b3b4f;
    border-color: white;
    min-width: 300px;
  }
  
  input[type="file"] {
    padding: 1px 2px;
  }
  
  a {
    color: #dfdfe2;
  }
  
  
  /* class selectors */
  .inline {
    width: unset;    /* removes the earlier rule that set all the input elements to width: 100%. */
    margin-right: 0.5em;
    margin-left: 0;
    margin-top: 0;
    margin-bottom: 0;
    vertical-align: middle;
  }