body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: #f0f0f0;
}

header {
    background: #333;
    color: #fff;
    padding: 0em;
}

nav a {
    color: #fff;
    margin-right: 1em;
    text-decoration: none;
}

main {
    padding: 2em;
}

footer {
    text-align: center;
    padding: 1em;
    background: #333;
    color: #fff;
}

.period-btn {
    border: 1px solid #17a2b8;
    color: #17a2b8;
    background-color: transparent;
    outline: none;
}

.period-btn:focus {
    background-color: #17a2b8;
    color: #fff;
}

		a {
			color: #FFFFFF;
		}

		textarea {
			-webkit-box-sizing: border-box;
			-moz-box-sizing: border-box;
			box-sizing: border-box;
			width: 100%;
			height: 100px;
		}

		table {
			border-collapse: collapse;
			width: 100%;
			font-size: 12px;
			color: brown;
		}

		.content_table {
			color: blue;
		}

		th {
			padding: 8px;
			color: black;
			text-align: center;
			border-bottom: 1px solid #ddd;
		}

		td {
			padding: 8px;
			color: green;
			text-align: center;
			border-bottom: 1px solid #ddd;
		}

		tr:hover {
			background-color: #f5f5f5;
		}

		.th_left {
			text-align: right;
		}

		.th_center {
			text-align: center;
		}

		.right_side {
			text-align: right;
		}

		.left_side {
			text-align: left;
		}

		input[type=text] {

			width: 100%;
			padding: 12px;
			border: 1px solid #ccc;
			border-radius: 4px;
			resize: vertical;

		}

		select {
			width: 100%;
			padding: 16px 20px;
			border: none;
			border-radius: 4px;
			background-color: #f1f1f1;
		}

		.buttonSubmit {
			padding: 16px 20px;
			background-color: white;
			color: black;
			border: 2px solid #555555;
			width: 100%;
		}

		.buttonSubmit:hover {
			background-color: #555555;
			color: white;
		}

		.alert {
			padding: 20px;
			background-color: #52aeda;
			color: white;
			opacity: 1;
			transition: opacity 0.6s;
			margin-bottom: 15px;
		}

		.alert.success {
			background-color: #4CAF50;
		}

		.alert.info {
			background-color: #2196F3;
		}

		.alert.warning {
			background-color: #ff9800;
		}

		.closebtn {
			margin-left: 15px;
			color: white;
			font-weight: bold;
			float: right;
			font-size: 22px;
			line-height: 20px;
			cursor: pointer;
			transition: 0.3s;
		}

		.closebtn:hover {
			color: black;
		}

		.counter_input {
			text-align: center;
			width: 100%;
			box-sizing: border-box;
			border: none;
		}

		.size_color_blue {
			color: blue;
			font-size: 1.5em;
		}

		.size_color_black {
			color: black;
			font-size: 1.5em;
		}

		.Hide_div {
			display: none;
		}

		.hidden_element {
			visibility: hidden;
		}

		.txt_align_center {
			text-align: center;
		}

		.txt_align_center_no_link {
			text-align: center;
		}

		.display_elemnt {
			display: none;
		}

		ul {
			list-style-type: none;
			margin: 0;
			padding: 0;
			overflow: hidden;
			/*background-color: #333333;*/
		}

		li {
			float: right;
		}

		li a {
			display: block;
			color: white;
			text-align: center;
			padding: 16px;
			text-decoration: none;
		}

		li a:hover {
			background-color: #111111;
		}