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CSS

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JavaScript

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HTML 

              
                <div class="container">
  <h1>Dark UI Kit</h1>
  <h2>Form Elements</h2>
  <div class="checkbox block">
    <em>Checkboxes</em>
    <input type="checkbox" id="checkbox1">
    <label for="checkbox1">Option One</label>
    <input type="checkbox" id="checkbox2">
    <label for="checkbox2">Option Two</label>
    <input type="checkbox" id="checkbox3">
    <label for="checkbox3">Option Three</label>
    <input type="checkbox" id="checkbox4">
    <label for="checkbox4">Option Four</label>
  </div>
  <div class="radio block">
    <em>Radio Buttons</em>
    <form>
      <input type="radio" id="radio1" name="radio-group">
      <label for="radio1">Option One</label>
      <input type="radio" id="radio2" name="radio-group">
      <label for="radio2">Option Two</label>
      <input type="radio" id="radio3" name="radio-group">
      <label for="radio3">Option Three</label>
      <input type="radio" id="radio4" name="radio-group">
      <label for="radio4">Option Four</label>
    </form>
  </div>
  <div class="text-input block">
    <form>
      <em>Text Inputs</em>
      <div class="form-group">
        <input type="text" id="username" />
        <label for="username">Username</label>
      </div>
      <div class="form-group">
        <input type="password" id="password" />
        <label for="password">Password</label>
      </div>
    </form>
  </div>
  <div class="text-input stacked block">
    <form>
      <em>Text Inputs (Stacked)</em>
      <div class="form-group">
        <input type="text" id="username2" />
        <label for="username2">Username</label>
      </div>
      <div class="form-group">
        <input type="password" id="password2" />
        <label for="password2">Password</label>
      </div>
    </form>
  </div>
</div>
!

CSS 

              
                /* webfont */
@import url('https://fonts.googleapis.com/css?family=Open+Sans:400,700,600,300');

/* setup */
body {
  font: 14px 'Open Sans', sans-serif;
  background: @darkbg; 
  color: @silver-light; 
}
* { box-sizing: border-box; }
.container { 
  width: 600px;
  margin: 40px auto;
  background: @default;
  padding: 20px;
  border: 5px solid @default-dark;
  .box-shadow(0 0 24px rgba(0,0,0,0.12));
  
  h1, h2 { padding: 0; margin: 0; .font-smooth; text-align: center; }
  h1 { font-weight: 300; font-size: 36px; line-height: 1.2em; }
  h2 { font-size: 16px; line-height: 1.4em; margin-bottom: 20px; }
  .block { 
    padding: 10px; 
    border: 2px solid @default-light;
    margin-top: 6px;
    em { 
      text-align: right; 
      display: block;
      font-style: normal; 
      color: @silver-darker; 
      margin-top: -4px;
      margin-bottom: 4px;
      font-size: 12px;
    }
  }
}

/* form ui variables */
@checkbox-radius: 6px; 
@ui-checkbox-size: 20px;
@ui-checkbox-offset: 2px; /* unfortunate hack to get precise vertical alignment */
@input-radius: 6px;
@font-size: 14px;
@label-width: 16%; /* set percent, stacked view only */

/* form elements */
.checkbox, .radio {
  form { display: inline-block; }
  input, label { cursor: pointer; }
  input { 
    opacity: 0;
    position: absolute;
    + label {
      line-height: @ui-checkbox-size + 2;
      display: inline-block;
      padding: 2px;
      margin: @ui-checkbox-offset @ui-checkbox-size - 12 -@ui-checkbox-offset 0;
      .transition;
      &:before {
        content: '';
        display: inline-block;
        vertical-align: middle;
        position: relative;
        top: -@ui-checkbox-offset;
        margin-right: 6px;
        border-radius: @checkbox-radius;
        height: @ui-checkbox-size;
        width: @ui-checkbox-size;
        border: 2px solid @default-lighter;
        .transition;
      }
      &:hover { 
        color: @silver;
        &:before {
          border-color: @green-bright;
        }
      }
    }
    &:checked {
      + label {
        color: @green-bright;
        &:before {
          background: @green-bright;
          border-color: @default-lighter;
        }
        &:hover:before { 
          border-color: @green-bright;
        }
      }   
    }
  }
}
.radio input + label:before { border-radius: 50%; }

.text-input {
  input {
    border-radius: @input-radius;
    outline: none;
    line-height: @font-size;
    font-size: @font-size;
    padding: 4px 8px;
    margin-right: 6px;
    background: transparent;
    border: 2px solid @default-lighter;
    .transition;
    
    &:focus { 
      border-color: @silver-dark;
      color: @silver-light;
    }
  }
  label {
    position: relative;
    float: left;
    top: 6px;
    margin-right: 10px;
    color: @silver-dark;
    cursor: pointer;
    .transition;
  }
  input:focus + label { color: @silver-light; }
  .form-group { display: inline-block; }
}

.stacked { 
  .form-group { 
    width: 100%; 
    display: block; 
    margin-bottom: 6px;
    label { width: @label-width; margin: 0; }
    input { width: 100 - @label-width; margin: 0; }
  } 
}

/* color variables */
@darkbg: #1f2336;
@default-lighter: 		#535a83;
@default-light: 		#474c6c; 
@default: 				#3c405c;
@default-dark: 			#343850;
@default-darker: 		#2a2d3e;
@silver-lighter: 		#eff5ff;
@silver-light: 			#d3d7e3;
@silver: 				#aeb8d6;
@silver-dark: 			#a4abc1;
@silver-darker: 		#8690af;
@green-bright: 			#3cff85;
@green-transparent: 	rgba(60, 255, 133, 0.7);

/* mixins */
.transition(@duration:0.25s, @ease:ease-in-out) {
  -webkit-transition: all @duration @ease;
  -moz-transition: all @duration @ease;
  -o-transition: all @duration @ease;
  transition: all @duration @ease;
}
.font-smooth(@fontsmooth: antialiased, @mozfontsmooth: grayscale ) {
  -webkit-font-smoothing: @fontsmooth;
  -moz-osx-font-smoothing: @mozfontsmooth;
  font-smoothing: @fontsmooth;
  text-rendering: optimizeLegibility;
}
.box-shadow(@arguments) {
  -webkit-box-shadow: @arguments;
  -moz-box-shadow: @arguments;
  box-shadow: @arguments;
}
!

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