/* ================================================== GLOBAL */

:root {
    --sky-color: #d3fcd3;
    --cloud-color: #f3faf3;
    --cloud-color-2: #e2f8e2;
    --board-bg: #fefff4;
    --board-border: #41422d;

    --piece-color: #f1d8ac;
    --piece-moves: #d55c01;

    --pillar-bg: #196;
    --pillar-border: #0a5c3e;

    --text-color: #4e4d44;
    --secondary-text-color: #4e4d44;
}

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

body {
    width: 1500px;
    height: 1000px;
    margin: auto;
    background-color: var(--sky-color);
    font-family: sans-serif;
    transition: background-color .4s;
    color: var(--text-color);
    overflow: hidden;
    position: relative;
}

button {
    padding: 14px 30px;
    color: var(--secondary-text-color);
    background-color: var(--piece-color);
    font-size: 14px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: .4s;
    box-shadow: 8px 8px 0px 0px rgba(51,51,51,0.4);
}

button:hover {
    transform: translate(4px, 4px);
    box-shadow: 4px 4px 0px 0px rgba(51,51,51,0.4);
}

/* ================================================== DAY-NIGHT */

body.night {
    --sky-color: #582c9b;
    --cloud-color: #8f5fd6;
    --cloud-color-2: #784bbd;
    --board-bg: #f4f4ff;
    --board-border: #2d3242;

    --piece-color: #a9e3d0;
    --piece-moves: #cd65ea;

    --pillar-bg: #254f7d;
    --pillar-border: #101051;

    --text-color: #e3e2eb;
    --endgame-color: #464555;
}

/* ================================================== SCREENS */

section.screen {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    position: absolute;
    top: 0; left: 0;
    transition: 1s cubic-bezier(.05,.55,.31,.96);
}

.screen:not(.active) {
    pointer-events: none;
    opacity: 0;
}

#main-menu:not(.active) {top: -100%}
#play-screen:not(.active) {top: 100%}

button.back-to-main {
    position: absolute;
    top: 20px; left: 20px;
    z-index: 100;
}

/* ================================================== MAIN MENU */

#main-menu {
    flex-direction: column;
}

#main-menu ul {
    list-style-type: none;
}

h1 {
    font-size: 90px;
    text-align: center;
}

h1 span {
    display: inline-block;
    -moz-transform:    scaleX(-1); /* Gecko */
    -o-transform:      scaleX(-1); /* Opera */
    -webkit-transform: scaleX(-1); /* Webkit */
    transform:         scaleX(-1); /* Standard */
}

#main-menu ul button {
    margin-top: 40px;
    padding: 20px 90px;
    font-size: 28px;
}

/* ================================================== BG Clouds */

#bg-clouds {
    width: 100%;
    height: 100%;
    position: fixed;
    top: 0; left: 0;
    z-index: 0;
}

#bg-clouds svg {
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
}

#bg-clouds svg:nth-child(2) {
    fill: var(--cloud-color);
    width: 330%;
    height: 330%;
    animation: clouds 60s infinite linear;
}

#bg-clouds svg:first-child {
    fill: var(--cloud-color-2);
    width: 300%;
    height: 300%;
    animation: clouds 50s infinite linear;
}

@keyframes clouds {
    0% {transform: translate(-50%, -50%) rotate(0)}
    100% {transform: translate(-50%, -50%) rotate(360deg)}
}