static/css/style.css

.navbar-light .navbar-brand {
    color: rgba(0, 0, 0, .9);
}

.navbar-light .navbar-brand {
    margin-left: auto;
    margin-right: auto;
}

body {
    margin: 0;
    padding: 0;
    font-family: sans-serif;
}

.formBox {
    margin-top: 50px;
    padding: 50px;
}

h1 {
    margin: 0;
    padding: 0;
    text-align: center;
    margin-bottom: 50px !important;
    text-transform: uppercase;
    font-size: 48px;
}

.inputBox {
    position: relative;
    box-sizing: border-box;
    margin-bottom: 40px;
}

.button {
    width: 100%;
    background: #00bcd4;
    color: #fff;
    border-radius: 0;
    border: none;
    outline: none;
    height: 50px;
    font-size: 24px;
}

.input {
    position: relative;
    width: 100%;
    height: 50px;
    background: transparent;
    border: none;
    outline: none;
    font-size: 24px;
    border-bottom: 2px solid rgba(0, 0, 0, .5);
}

.inputText {
    position: absolute;
    line-height: 50px;
    font-size: 24px;
    transition: .5s;
    opacity: 0.5;
}

.focus .inputText {
    transform: translateY(-30px);
    font-size: 18px;
    opacity: 1;
    color: #00bcd4;
}

.btn_train {
    width: 100%;
    background: red;
    color: #fff;
    border-radius: 0;
    border: none;
    outline: none;
    height: 50px;
    font-size: 24px;
}