/* reset css  */
*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html,body{
    font-family: 'Oswald', sans-serif;
    /* ho tro hieu ung cho back_to_top  */
    scroll-behavior: smooth;
}

.container{
    max-width: 1044px;
    /* chinh margin cach deu 2 ben, ko tinh tren duoi  */
    margin: 0 auto;
 }

header{
    /* background-color: black;  */
    position: absolute;
    z-index: 5;
    /* sau khi header nằm đè lên banner nhuwg chiều rộng bị thay đổi khsc với banđầu, chr cần dùng width 100% để dàn ra bằng chiều rộng body cha  */
    width: 100%;
 }

 /* thuoc tinh moi thay the cho float:left là flex-box */
 header .header_content{
    display: flex;
    /* can chinh truc ngang  */
    justify-content: space-between;
    /* can chinh truc doc  */
    /* align-items: flex-end;
    flex-direction: column;
    height: 80vh; */
    /* dao nguoc vi tri cac phan tu nhanh chong ma ko can sua html 
    flex-direction: row-reverse; tren dong
    hoac
    flex-direction: column-reverse; tren cot */
    padding: 40px 0;
    align-items: center;
    
 }

 /* header_logo */
 header .header_logo a{
    color: white;
    text-decoration: none;
    font-size: 40px;
 }

 header .header_nav ul{
     list-style: none;
 }

 header .header_nav nav ul li{
    display: inline;
    margin-right: 15px;
 }

 header .header_nav li a{
     text-decoration: none;
     color: white;
     font-size: 20px;
     /* text-transform: uppercase; dung viet hoa viet thuong cac chus */
     /* thoi gian chuyen dong cua hieu ung  */
    transition: 1s all;
 }

.container .header_nav li a.active{
    /* cach goi 1: .container .header_nav li a.active{}  */
    /* cach goi 2: 
    .container .header_nav li a{}
    a.active{} */
    color: red;
}

/* tao hiue ung chuyen mau hoac su kien hieu ung dung hover trong the a  */
header .header_nav li a:hover{
    color: red;
    
}


/* banner  */
.banner {
    background-image: url(./../img/home_slider.jpg);
    height: 80vh;
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    position: relative; 
}

.banner .banner_content{

    /* cach 1  */
    display:flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    /* phai truyen them height bang height cua pha tu cha can can chinh theo, neu ko align-items: center; ko xay ra hieu ung  */
    height: 80vh;

    /* cach 2: dung position: relative va position: absolute 
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center; */
}

.banner .banner_content{
    text-align: center;
    color:white;
    
}

.banner .banner_content p{
    font-size: 20px;
    line-height: 20.8px;
    margin: 50px 0 0 0;
}


.banner .banner_content h1{
    font-size: 75px;
    line-height: 90px;
    margin: 10px 0 20px 0;

}

.banner .banner_content button{
     background-color: #e62b4a;
     padding: 15px 30px;
     text-transform: uppercase;
     font-size: 16px;
     color: white;
     border: 0;
     transition: 1s;
     /* tao gia tri bieu trung hanh dong khi nguoi dung click vao  */
     cursor: pointer;
}

.banner .banner_content button:hover{
     background-color: #af2239;
}


/* TAO ANIMATION  */
/* @keyframes giúp định nghĩa các hiệu ứng animation  */
/* @keyframe + tên hiệu ứng (tiếng việt hay tiếng anh đều được */
@keyframes arrowGoDown {
    from{
        opacity: 1;
        transform: translateY(0);
    }
    to{
        opacity: 0;
        transform: translateY(40px);
    }
}

.banner .banner_content i {
    /* animation-name: gọi tên hiệu ứng là tên mình tự đặt trong keyframe  */
    /* animation-duration: tổn thời gian hiệu ứng chạy từ lúc bắt đầu đến lúc kết thúc  */
    animation-name: arrowGoDown;
    animation-duration: 2s;
    /* animation-iteration-count: số lần lặp lại của hiệu ứng, nếu muốn hiệu ứng lặp lại vô tận fugn infinite  */
    animation-iteration-count: infinite;
}


/* service  */
.service{
    background-color:rgb(7, 7, 7); 
    padding: 60px 0;
    text-align: center;
    color: white;
}

.service .service_title .subtitile{
    color: rgb(141, 48, 48);
}

.service .service_title h2{
    font-size: 50px;
    font-weight: 400;
    color: white;
}

.service .service_title p:last-child{
    color: grey;
    font-size: 16px;
    font-weight: bold;
}

.service .service_content .service_item{
    padding: 25px 20px 10px 0;
}

.service .service_content .service_item .item_bg{
    background-color: white;
    color: grey;
    height: 220px;
    display: flex;
    align-items: center;
    flex-direction: column;
    justify-content: center;
    position: relative;
}

.service_item .item_bg i{
    font-size: 40px;
}

.service_item .item_bg p{
    font-size: 18px;
}

.service_item .item_bg::after{
    /* luu y khi su dung before/ after: khi sd phai co thuoc tinh content di kem */
    content:" ";
    width: 3px;
    height: 0%;
    background-color: #e62b4a;
    position: absolute;
    top: 0;
    right: 0;
    /* tao hieu ung cho thanh mau do  */
    transition: 0.5s all;

}

.service_item .item_bg:hover::after{
    height: 100%;
}

/* cach chinh sua tu code css cua thu vien slick carousel  */
.service .slick-dots li button:before{
    font-size: 12px;
    color: rgb(255, 255, 255);
}

.service .slick-dots li.slick-active button::before{
    color: rgb(203, 39, 39);
}


/* blog  */
.blog{
    text-align: center;
    padding: 60px 0;
}

.blog .blog_title .sub_title{
    font-size: 12px;
    color:grey;
}

.blog_title h2{
    font-size: 50px;
    font-weight: 400;
}

.blog_title p{
    color:grey;
    font-weight: bold;
}

                  /* LAYOUT GRID QUAN TRỌNG      */
 /* cac dan layout grid bang css  */
.blog .blog_content{
    display: grid;
    margin-top: 50px;
    /* grid-template-columns: 100px 200px 300px 400px 500px ;  */
    /* (hoac chia 4 cot bang nhau)  */
    grid-template-columns: repeat(4, 1fr);
    /* thuoc tinh trong grid: gap chinh khoang cach can bang giua cac phan tu voi nhau, thay cho padding, co the dung gap cho ca flex-box  */
    gap: 20px;
}

.blog .blog_content .blog_item img {
    width: 100%;
    height: 100%;
    /* can doi hinh ko bi be khi chinh height vaf width  */
    object-fit: cover;
    /* chỉnh ảnh nhiều chế độ  */
    filter:grayscale(60%) contrast(60%);
}

.blog .blog_content .blog_item:first-child {
    /* grid_column dùng để gom cột: gt 1 là thứ tự cột muốn bắt đầu gom / span số cột muốn gom   */
    grid-column: 1/ span 2;
     /* grid_row dùng để gom cột: gt 1 là thứ tự dòng muốn bắt đầu gom / span số dòng muốn gom   */
    grid-row: 1/ span 2;
    
}

.blog .blog_content .blog_item:last-child {
    grid-column: 3/ span 2;
    grid-row: 3/ span 2;
}

.blog_content .blog_item{
    position: relative;


}

.blog_content .blog_item .blog_overlay{
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(237, 26, 62, 0.567);
   
    padding: 30px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    opacity: 0;
    transition: 0.5s all;
}

.blog_item .blog_overlay .blog_icon{
    text-align: right;
}

.blog_item .blog_overlay .blog_text{
    text-align: left;
    color: white;
}

.blog_item:hover .blog_overlay{
    opacity: 1;
    
}

.blog_item .blog_overlay .blog_icon i{
    background-color: white;
    padding: 10px;
    transform: translateY(30px);
    color: black;
    transition: 0.5s all;
}

.blog_item:hover .blog_icon i{
    transform: translateY(0);
}

.blog_item .blog_overlay .blog_text{
    transform: translateY(30px);
    transition: 0.5s all;
}

.blog_item:hover .blog_text{
    transform: translateY(0);
}


/* number  */
.number{
    background-color: black;
    padding: 60px 0;
    color: white;
}

.number .number_content{
    display: flex;
    justify-content: space-around;
    text-align: center;
}

.number_content .number_item h3{
    font-size: 50px;
    font-weight:100 ;
}

.number_content .number_item p{
    color: grey;
    font-size: 18px;
}

/* CÀI ĐẶT VÀ TẠO THƯ VIỆN CHẠY SỐ  */


/* experience  */
.exp{
    background-image: url(./../img/bussiness_img_1.jpg);
    padding: 60px 0;
    background-repeat: no-repeat;
    color: white;
    background-size: cover;
    text-align: center;
    /* khóa background nằm theo vùng nhìn đến khi qua section khác mới hết  */
    background-attachment: fixed;
}

.exp .exp_title .sub_title{
    color: red;
    font-size: 12px;
}

.exp .exp_title h2{
    font-size: 45px;
    margin-bottom: 15px;
    font-weight: lighter;
}

.exp .exp_title p {
    color: grey;
    font-weight: bold;
}


/* contact  */
.contact{
    padding: 60px 0;
    text-align: center;
}

.contact .contact_title h2{
    text-transform: uppercase;
    font-size: 50px;
    font-weight:400;
}

.contact .contact_title p{
    color:grey;
    margin: 30px 0;
}

.contact .contact_content{
    display: flex;
    justify-content: space-around;
    gap: 20px;
}

.contact .contact_content .contact_form form{
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    height: 100% ;
}

.contact .contact_content .contact_map{
     width: 60%;
}

.contact .contact_content .contact_form{
    width: 40%;
}

.contact .contact_content .contact_form form input, textarea{
    padding: 15px;
}

.contact .contact_content .contact_form form button{
    padding: 20px;
    background-color: black;
    color: white;
    text-transform: uppercase;
    border: none;
    cursor: pointer;
    transition: 0.5s all;
}

.contact .contact_content .contact_form form button:hover{
    background-color: #af2239;
}

/* mui ten nam goc phai  */
/* back_to_top  */

.back_to_top{
    position: fixed;
    right: 20px;
    bottom: 20px;
    background-color: #e62b4a;
    width: 50px;
    height: 50px;
    line-height: 50px;
    text-align: center;
    border-radius: 8px;
}

.back_to_top a{
    display: inline-block;
    width: 100%;
    height: 100%;
    color: white;
}


/* footer  */
footer{
    background-color: black;
    padding: 100px 0;
    color: white;
}

footer .footer_cover{
    display: flex;
    justify-content: space-between;
    
}

footer .footer_cover .footer_content {
    display: flex;
    gap: 0 10px;
    font-weight: 100;
    font-size: 15px;
    padding-top: 10px;
}

footer .footer_cover .footer_content i{
    margin-top: 4px;
}

footer .footer_cover .footer_icon i{
    background-color: rgba(128, 128, 128, 0.552);
    width: 50px;
    height: 50px;
    line-height: 50px;
    text-align: center;
    border:none;
    border-radius: 50%;
    padding-top: -10px;
    margin: 0 4px;
}