/*------------------------------ CÀI ĐẶT CHUNG ------------------------------*/
/*---------------------------------------
　Các thẻ cơ bản
---------------------------------------*/
*{
	box-sizing: border-box;
	overflow-wrap: break-word;
}
h1, h2, h3{
	font-weight: normal;
}
/* Tiêu đề chính - cỡ chữ lớn nhất */
h1{
	margin: 30px auto 20px auto;
	padding: 0;
	font-family: 'Segoe UI', 'Arial', 'Helvetica', sans-serif;
	font-size: 2.4rem;
	font-weight: 700;
	line-height: 1.4;
	vertical-align: baseline;
	color: #2c3e50;
}
/* Tiêu đề phụ - có viền trang trí */
h2{
	margin: 0 0 50px 0;
	padding: 0;
	font-family: 'Segoe UI', 'Arial', 'Helvetica', sans-serif;
	font-size: 2.0rem;
	font-weight: 600;
	line-height: 1.4;
	display:flex;
	align-items: center;
	justify-content: center;
	color: #34495e;
}
h2::before,
h2::after{
	content: "";
	flex-grow:1;
	border-top: 2px solid #3498db;
}
h2:before {
	margin-right: 1rem; 
}
h2:after {
	margin-left: 1rem; 
}
/* Tiêu đề nhỏ */
h3{
	margin: 0 0 40px 0;
	padding: 0;
	font-family: 'Segoe UI', 'Arial', 'Helvetica', sans-serif;
	font-size: 1.8rem;
	font-weight: 500;
	line-height: 1.6;
	color: #2c3e50;
}

/* Liên kết - màu xanh chuyên nghiệp */
a{ 
	color: #3498db; 
	text-decoration: none; 
	transition: all 0.3s ease;
}
a:hover, a:visited:hover{ 
	color: #e67e22; 
	text-decoration: underline;
}

/* Hiệu ứng hover cho hình ảnh */
a:hover img{
	opacity: 0.8;
	filter: alpha(opacity=80);
	-ms-filter: "alpha( opacity=80 )";
	transform: scale(1.05);
}
a,
a:hover img{
	transition-property: all;
	transition: 0.3s ease;
}

/* Các phần tử cơ bản */
/* Hình ảnh responsive */
img{
	border: 0;
	height: auto;
	max-width: 100%;
	vertical-align: bottom;
	border-radius: 8px;
}
/* Đoạn văn */
p{
	margin: 0 0 30px 0;
	padding: 0;
	line-height: 1.8;
}
/* Danh sách */
ul,
ol{
	margin: 0 0 30px 30px;
	padding: 0;
	line-height: 1.8;
}
/* Đường kẻ ngang */
hr{
	margin: 40px 0;
	padding: 0;
	border: 0;
	height: 2px;
	background: linear-gradient(to right, transparent, #3498db, transparent);
	clear: both;
}

/* Màu bôi đen khi chọn text */
::selection {
	background: #3498db;
	color: white;
}
::-moz-selection {
	background: #3498db;
	color: white;
}

/*---------------------------------------
　Các class chung (giao diện)
---------------------------------------*/
/* Clearfix - xóa float */
/* Xóa bỏ float */
.cf{ clear: both; }
.cf:before,
.cf:after{
	content: "";
	display: table;
}
.cf:after{ clear: both; }

/* Kiểu chữ đặc biệt */
.small{ font-size: 1.3rem; line-height: 1.8; color: #7f8c8d; }
.big{ font-size: 3.2rem; font-weight: 700; color: #2c3e50; }
.red{ color: #e74c3c; font-weight: 600; }

/* Liên kết hướng dẫn với mũi tên */
.link-howto{
	position: relative;
	margin: 0;
	padding: 0 5px 0 20px;
	display: inline-block;
}
.link-howto:before{
	position: absolute;
	display: block;
	content: "";
	width: 6px;
	height: 6px;
	border-top: 2px solid #3498db;
	border-right: 2px solid #3498db;
	-webkit-transform: rotate(45deg);
	-moz-transform: rotate(45deg);
	-ms-transform: rotate(45deg);
	filter: progid:DXImageTransform.Microsoft.BasicImage(rotation=1);
	transform: rotate(45deg);
	left: 5px;
	top: calc(50% - 3px);
	transition: all 0.3s ease;
}
.link-howto:hover:before{
	border-color: #e67e22;
	transform: rotate(45deg) translateX(3px);
}

/* Vị trí căn chỉnh */
.center{
	margin: 0 auto 40px auto;
	text-align: center;
	clear: both;
}
.left,
.right{
	max-width: 50%;
	padding: 20px;
	vertical-align: bottom;
	background: #f8f9fa;
	border-radius: 10px;
	box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}
.left{
	float: left;
	margin: 0 40px 30px 0;
}
.right{
	float: right;
	margin: 0 0 30px 40px;
}

/*---------------------------------------
　Bố cục trang
---------------------------------------*/
html{
	font-size: 62.5%;
	-webkit-text-size-adjust: 100%;
	-ms-text-size-adjust: 100%;
	scroll-behavior: smooth;
}
body{
	margin: 0 auto;
	padding: 0;
	font-family: 'Segoe UI', 'Roboto', 'Arial', 'Helvetica', sans-serif;
	font-size: 1.6rem;
	line-height: 1.8;
	color: #2c3e50;
	background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
	min-height: 100vh;
}
/* Container chính */
.main{
	position: relative;
	margin: 0 auto 40px auto;
	padding: 30px 20px;
	text-align: center;
	clear: both;
	background: white;
	border-radius: 15px;
	box-shadow: 0 10px 30px rgba(0,0,0,0.1);
	max-width: 1200px;
}
.main:before,
.main:after {
	content: "";
	display: table;
}
.main:after { clear: both; }

/* Các phần tử section */
section{
	margin: 0 0 80px 0;
	padding: 0;
}
section section section{
	margin-bottom: 40px;
}

/*------------------------------ CÀI ĐẶT TRANG ------------------------------*/
/*---------------------------------------
　Các thành phần chung của trang
---------------------------------------*/
/* Văn bản giới thiệu */
.intro_text{
	line-height: 2.2;
	font-size: 1.7rem;
	color: #34495e;
	margin-bottom: 30px;
}
/* Nút bấm chính */
button{
	display: block;
	width: 80%;
	max-width: 400px;
	margin: 15px auto 25px;
	padding: 18px 30px;
	font-size: 1.8rem;
	font-weight: 600;
	color: #fff;
	background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
	border: 0;
	border-radius: 50px;
	outline: 0;
	cursor: pointer;
	transition: all 0.3s ease;
	box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}
button:hover{
	background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
	transform: translateY(-2px);
	box-shadow: 0 6px 20px rgba(0,0,0,0.3);
}
/* Nút quay lại */
#back a{
	display: block;
	width: 80%;
	max-width: 400px;
	margin: 25px auto;
	padding: 15px 30px;
	font-size: 1.7rem;
	font-weight: 500;
	color: #3498db;
	background: white;
	border: 3px solid #3498db;
	border-radius: 50px;
	outline: 0;
	text-decoration: none;
	transition: all 0.3s ease;
	box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
#back a:hover{
	color: white;
	background: #3498db;
	transform: translateY(-2px);
	box-shadow: 0 6px 20px rgba(52, 152, 219, 0.4);
}
/* Khung video, hình ảnh và camera */
.input_video,
.image_area,
.shoot_area{
	border: 3px solid #ecf0f1;
	border-radius: 15px;
	max-width: 100%;
	overflow: hidden;
	box-shadow: 0 8px 25px rgba(0,0,0,0.1);
	transition: all 0.3s ease;
}
.input_video:hover,
.image_area:hover,
.shoot_area:hover{
	border-color: #3498db;
	box-shadow: 0 12px 35px rgba(52, 152, 219, 0.2);
}


/* Phần hướng dẫn sử dụng */

/* Container hướng dẫn */
.howto_inner{
	width: 96%;
	margin: auto;
	background: #f8f9fa;
	padding: 30px;
	border-radius: 15px;
	box-shadow: 0 5px 20px rgba(0,0,0,0.1);
}
.howto_inner h3{
	margin: 20px 0 40px;
	text-align: center;
	color: #2c3e50;
	font-size: 2.2rem;
	font-weight: 600;
	position: relative;
}
.howto_inner h3:after{
	content: "";
	position: absolute;
	bottom: -10px;
	left: 50%;
	transform: translateX(-50%);
	width: 80px;
	height: 4px;
	background: linear-gradient(to right, #3498db, #9b59b6);
	border-radius: 2px;
}
/* Khung chứa hình ảnh hướng dẫn */
.howto_image{
	display: flex;
	flex-wrap: wrap;
	justify-content: space-around;
	margin: 0 auto 30px;
	gap: 20px;
}
.howto_image img{
	width: 46%;
	border-radius: 12px;
	box-shadow: 0 6px 20px rgba(0,0,0,0.15);
	transition: all 0.3s ease;
}
.howto_image img:hover{
	transform: scale(1.05);
	box-shadow: 0 10px 30px rgba(0,0,0,0.25);
}