:root {
  --primary-color: #033F4A;
  --second-color: #0558EE;
  --third-color: #36C2CE;
  --fourth-color: #77E4C8;
}

* {
  box-sizing: border-box;
}

.row::after {
  content: "";
  clear: both;
  display: table;
}

[class*="col-"] {
  float: left;
  padding: 15px;
}

html {
  font-family: "Lucida Sans", sans-serif;
}

.header {
  background-color: var(--primary-color);
  color: #ffffff;
  padding: 15px;
}

.menu ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
}

.menu li {
  margin-bottom: 20px;
}

.menu li {
  padding: 8px;

  background-color: var(--second-color);
  color: #ffffff;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
  font-size: 14px;
  text-decoration: none;
}

.menu a {
  text-decoration: none;
}

.menu li:hover {
  background-color: var(--primary-color);
  cursor: pointer;
}

.menu a.active li {
  background-color: var(--primary-color);
  cursor: pointer;
}

.aside {
  background-color: var(--second-color);
  padding: 15px;
  color: #ffffff;
  text-align: center;
  font-size: 14px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12), 0 1px 2px rgba(0, 0, 0, 0.24);
}

.footer {
  background-color: var(--primary-color);
  color: #ffffff;
  text-align: center;
  font-size: 12px;
  padding: 15px;
}

.btn_chuyen_doi {
  background-color: var(--primary-color);
  padding: 11px;
  border: none;
  color: white;
}

/* For mobile phones: */
[class*="col-"] {
  width: 100%;
}

@media only screen and (min-width: 600px) {

  /* For tablets: */
  .col-s-1 {
    width: 8.33%;
  }

  .col-s-2 {
    width: 16.66%;
  }

  .col-s-3 {
    width: 25%;
  }

  .col-s-4 {
    width: 33.33%;
  }

  .col-s-5 {
    width: 41.66%;
  }

  .col-s-6 {
    width: 50%;
  }

  .col-s-7 {
    width: 58.33%;
  }

  .col-s-8 {
    width: 66.66%;
  }

  .col-s-9 {
    width: 75%;
  }

  .col-s-10 {
    width: 83.33%;
  }

  .col-s-11 {
    width: 91.66%;
  }

  .col-s-12 {
    width: 100%;
  }
}

@media only screen and (min-width: 768px) {

  /* For desktop: */
  .col-1 {
    width: 8.33%;
  }

  .col-2 {
    width: 16.66%;
  }

  .col-3 {
    width: 25%;
  }

  .col-4 {
    width: 33.33%;
  }

  .col-5 {
    width: 41.66%;
  }

  .col-6 {
    width: 50%;
  }

  .col-7 {
    width: 58.33%;
  }

  .col-8 {
    width: 66.66%;
  }

  .col-9 {
    width: 75%;
  }

  .col-10 {
    width: 83.33%;
  }

  .col-11 {
    width: 91.66%;
  }

  .col-12 {
    width: 100%;
  }
}

input[type=text],
select,
textarea {
  width: 100%;
  padding: 12px;
  border: 1px solid #ccc;
  border-radius: 4px;
  resize: vertical;
}

label {
  padding: 12px 12px 12px 0;
  display: inline-block;
}

input[type=submit] {
  background-color: #04AA6D;
  color: white;
  padding: 12px 20px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  float: right;
}

input[type=submit]:hover {
  background-color: #45a049;
}

.container {
  border-radius: 5px;
  background-color: #f2f2f2;
  padding: 20px;
}

.col-25 {
  float: left;
  width: 25%;
  margin-top: 6px;
}

.col-75 {
  float: left;
  width: 75%;
  margin-top: 6px;
}

/* Clear floats after the columns */
.row::after {
  content: "";
  display: table;
  clear: both;
}

/* Responsive layout - when the screen is less than 600px wide, make the two columns stack on top of each other instead of next to each other */
@media screen and (max-width: 600px) {

  .col-25,
  .col-75,
  input[type=submit] {
    width: 100%;
    margin-top: 0;
  }
}