:root {
    --primary: #fc6304;
}

*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent; 
}

body{
    height: 100vh;
    display: flex;
    text-align: center;
    flex-direction: column;
    gap: 40px;
    align-items: center;
    justify-content: center;
    background: radial-gradient(at center, #10264deb, #000);
    color: #fafafa;
    font-family: "Nerko One", sans-serif;
    font-weight: 400;
    font-style: normal;
    font-style: 10px;
}

h2{
    font-size: 2.5rem;
}

main{
    position: relative;
}

#ctr-arm{
    display: flex;
    gap: 16px;
    margin: 16px 0;
}

#ctr-arm span{
    background-size: contain;
    background-position: center;
    width: 150px;
    height: 150px;
    cursor: pointer;
}

#ctr-arm span:active{
    transform: scale(1.1);
}

.active{
    filter: drop-shadow(0px 0px 15px var(--primary));
    transform: scale(1.1);
}

#rock{
    background-image: url('http://codetheworld.io/wp-content/uploads/2024/09/stone.png');
}

#paper{
    background-image: url('http://codetheworld.io/wp-content/uploads/2024/09/paper.png');
}

#scissor{
    background-image: url('http://codetheworld.io/wp-content/uploads/2024/09/scissor.png');
}

#btn-start,
#btn-reset{
    font-family: "Nerko One", cursive;
    font-size: 1.8rem;
    background: var(--primary);
    color: #fafafa;
    border: none;
    outline: none;
    cursor: pointer;
    padding: 6px 30px;
    border-radius: 25px;
}

#btn-start:hover,
#btn-reset:hover{
    transform: scale(1.2);
    box-shadow: 4px 4px 10px #00000033;
}

#pvp{
    display: flex;
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    align-items: center;
    justify-content: center;
}

#pvp span {
    width: 100%;
    aspect-ratio: 1/1;
    background-size: contain;
    background-position: center;
}

#pvp p{
    font-size: 2.5rem;
}

#btn-reset{
    position: absolute;
    bottom: -10%;
}

.cell{
    width: 100%;
    height: 100%;
    position: relative;
    overflow: hidden;
    mask-image: linear-gradient(to bottom, 
    #3d000000,
    #3d0000 20%,
    #3d0000 80%,
    #3d000000);
}

.cell span:nth-child(1){
    background-image: url(https://codetheworld.io/wp-content/uploads/2024/09/stone.png);
}

.cell span:nth-child(2){
    background-image: url(https://codetheworld.io/wp-content/uploads/2024/09/paper.png);
}

.cell span:nth-child(3){
    background-image: url(https://codetheworld.io/wp-content/uploads/2024/09/scissor.png);
}

.cell span{
    position: absolute;
    left: 0;
    top: 100%;
    width: 100%;
    height: 100%;
    animation: autoSlide 2s linear infinite;
    animation-delay: calc((2s / 3) * (3 - var(--i)) 8 -1); 
}

@keyframes autoSlide {
    to {
        top: -200%;
    }
}

#result {
    position: absolute;
    font-size: 5rem;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-shadow: 0px 0px 60px #000000,
    0px 0px 60px #000000,
    0px 0px 60px #000000;
    padding: 30px 80px;
    pointer-events: none;
}

#pvp,
#result {
    display: none;
}

/* Cho màn hình điện thoại */
@media (max-width: 768px) {
    body {
        gap: 20px;
    }

    h2 {
        font-size: 1.8rem;
    }

    #ctr-arm {
        flex-direction: row; /* Giữ cho các lựa chọn nằm ngang */
        gap: 10px;
        justify-content: center; /* Căn giữa các lựa chọn */
    }

    #ctr-arm span {
        width: 120px; /* Thu nhỏ hình ảnh */
        height: 120px;
        background-size: cover; /* Đảm bảo hình ảnh được bao phủ toàn bộ vùng hiển thị */
    }

    #btn-start,
    #btn-reset {
        font-size: 1.2rem;
        padding: 5px 20px;
    }

    #pvp {
        flex-direction: row; /* Giữ cho các lựa chọn nằm ngang */
        gap: 10px;
        justify-content: center; /* Căn giữa các lựa chọn */
    }

    #pvp p {
        font-size: 1.8rem;
    }

    #result {
        font-size: 3rem;
        padding: 20px 50px;
    }
}