* {
    margin: 0;
    padding: 0;
    font-family: 'Ubuntu', sans-serif;
}
html {
    height: 100%;
    text-align: center;
}
body {
    background-image: linear-gradient(to left bottom, #000000, #121212, #1d1d1d, #282828, #333333);    height: 100%;
    color: #bbb;
}

ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    margin-right: 20px;
}

li {
    float: right;
}

li a {
    margin-top: 20px;
    margin-right: 10px;
    display: block;
    color: #bbb;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    border-bottom: 3px solid transparent;
    font-size: larger;

}

li a:hover {
    color: #777;
    border-bottom: 3px solid #777;
}

input {
    margin-top: 30px;
    margin-left: 10px;
}

* {box-sizing: border-box}
  .container input[type=text], .container input[type=password] {
  width: 100%;
  padding: 10px;
  margin: 5px 0 22px 0;
  display: inline-block;
  border: 5px, solid, #555;
  border-radius: 10px;
  background: #f1f1f1;
}

input[type=text], input[type=password] {
    width: 20%;
    padding: 10px;
    display: inline-block;
    border: 5px, solid, #555;
    border-radius: 10px;
    background: #f1f1f1;
}
input[type=text]:focus, input[type=password]:focus {
    background-color: #ddd;
    outline: none;
  }

.container {
    width: 40%;
    margin: auto;
    text-align: center;
    border: 5px solid #aaa;
    border-radius: 20px;
    padding: 30px;
    height: 80%;
    margin-top: 30px;
}

.sicontainer {
    height: 60%;
}

#grammarPoint {
    width: 8%;
    height: 40px;
    border-radius: 10px;
    margin-left: 5px;
    padding: 2px;
}

.big {
    height: 40px;
    border-radius: 10px;
    margin-left: 10px;
    padding: 12px;
}

.submit:hover {
    background-color: #777;
}

.submit, .add {
    width: 5%;
    height: 40px;
    border-radius: 10px;
    margin-left: 5px;
}

.submit {
    width: 15%;
}

.submit:hover, .add:hover {
    background-color: #555;
}

form {
    height: 100%
}

table, th, td {
    margin: auto;
    border: 3px solid #555;
    border-collapse: collapse;
}

table {
    margin-top: 20px;
    width: 90%;
}

tr {
    text-align: center;
}

input[type=number] {
    width: 5%;
    padding: 10px;
    display: inline-block;
    border: 5px, solid, #555;
    border-radius: 10px;
    background: #f1f1f1;
}
input[type=text]:focus {
    background-color: #ddd;
    outline: none;
  }

a {
    text-decoration: none;
    color: #bbb;
}

td:hover i{
    color: #555;
}

th {
    background-color: #333;
}

#inside {
    background-color: transparent;
    width: 100%;
    margin: 0;
    border: 0;
    color: #bbb;
}

#inside::placeholder {
    color: #999;
}

th td {
    background-color: #666;
}