* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    user-select: none;
}

a:focus {
    outline: 0;
}

html {
    background: #313940;
}

body {
    min-height: 100vh;
    background-color: #043866;
    font-family: "Open Sans", Arial, Helvetica, sans-serif;
    background: #023b6d;
    overflow-x: hidden;
}

.header {
    text-align: center;
    width: 100%;
    border-bottom: 1px solid;
    border-image-slice: 1;
    border-image-source: linear-gradient(to left, #38495a, #a2abb3, #38495a);
}

.header-title {
    line-height: 60px;
    font-weight: 300;
    color: #fff;
}

.main {
    min-height: calc(100vh - 110px);
    padding: 60px 10px 0;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: space-between;
    width: 100%;
    max-width: 1140px;
    margin: 0 auto;
}

.btn-container {
    display: flex;
    justify-content: space-between;
    width: 306px;
    height: 40px;
    margin: 0 auto;
    margin-bottom: 80px;
}

.btn {
    width: 150px;
    height: 40px;
    padding: 0 10px;
    background-color: #454c53;
    border: 0;
    border-radius: 2px;
    font-family: "Open Sans", sans-serif;
    font-size: 16px;
    font-weight: 300;
    color: #fff;
    outline: 0;
    cursor: pointer;
    transition: 0.3s;
}

.btn:not(.btn-active):hover {
    background-color: #515961;
}

.btn:active {
    background-color: #00c9b7;
}

.btn-active {
    background-color: #00b4a4;
}

.btn-active:hover {
    background-color: #00c9b7;
}

.piano {
    position: relative;
    display: flex;
    justify-content: space-between;
    width: 100%;
    height: 350px;
    max-width: 700px;
    margin: 0 auto 60px;
}

.piano-key {
    position: relative;
    width: 100px;
    height: 350px;
    background-color: rgba(255, 255, 255, 0.85);
    border: 4px solid #313940;
    border-radius: 0px 0px 12px 12px;
    transition: 0.3s;
    cursor: pointer;
}

.piano-key:hover {
    background-color: rgb(180, 252, 248);
}

.keys-sharp {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 72px;
    right: 72px;
    display: flex;
    justify-content: space-between;
    pointer-events: none;
}

.piano-key.sharp {
    width: 54px;
    height: 170px;
    background-color: #313940;
    border: 0;
    border-radius: 0px 0px 9px 9px;
    top: 0;
    z-index: 3;
    pointer-events: auto;
    transform-origin: center top;
}

.piano-key.sharp:hover {
    background-color: #04213a;
}

.piano-key.piano-key-active,
.piano-key.sharp.piano-key-active {
    transform: scale(0.9);
}

.piano-key.none {
    background-color: transparent;
    border: 0;
    border-radius: 0;
    pointer-events: none;
}

.piano-key::before,
.piano-key::after {
    content: attr(data-note);
    position: absolute;
    width: 40px;
    height: 40px;
    font-size: 26px;
    line-height: 40px;
    text-align: center;
    color: #a2abb3;
    bottom: -45px;
    left: 20px;
    transition: 0.3s;
}

.piano-key::after {
    display: none;
    content: attr(data-letter);
}

.piano-key:hover::before,
.piano-key:hover::after {
    color: #d7dfe6;
}

.sharp:active {
    border-top: 0;
}

.piano-key.sharp::before,
.piano-key.sharp::after {
    bottom: 175px;
    left: 7px;
}

.piano-key.letter::before {
    display: none;
}

.piano-key.letter::after {
    display: block;
}

.piano-key-letter::before {
    content: attr(data-letter);
}

.piano-key-remove-mouse:active::before {
    color: #a2abb3;
}

.piano-key-active-pseudo:hover::after,
.piano-key-active-pseudo:hover::before,
.piano-key-active::after,
.piano-key-active::before {
    color: #00b4a4;
}

.playing {
    transform: scale(0.9);
    background-color: rgb(29, 235, 217);
}

.fullscreen {
    position: fixed;
    top: 120px;
    right: 40px;
    width: 40px;
    height: 40px;
    background-color: rgba(255, 255, 255, 0.3);
    border: 0;
    outline: 0;
    background-size: contain;
    transition: 0.3s;
    cursor: pointer;
    background-image: url("assets/svg/fullscreen-open.svg");
}

.fullscreen:hover {
    background-color: rgba(255, 255, 255, 0.5);
}

:-webkit-full-screen .fullscreen {
    background-image: url("assets/svg/fullscreen-exit.svg");
}

.footer {
    border-top: 1px solid;
    border-image-slice: 1;
    border-image-source: linear-gradient(to left, #38495a, #a2abb3, #38495a);
}

.footer-container {
    padding: 0 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    max-width: 1140px;
    margin: 0 auto;
}

.github {
    display: block;
    width: 120px;
    height: 45px;
    padding-left: 45px;
    background-image: url("assets/svg/github.svg");
    background-size: 35px;
    background-repeat: no-repeat;
    background-position: left center;
    line-height: 45px;
    color: #cbd5de;
    font-size: 16px;
    font-family: "Open Sans", sans-serif;
    transition: 0.3s;
}

.github:hover {
    color: #fff;
}

.rss {
    display: block;
    position: relative;
    font-family: "Open Sans", sans-serif;
    width: 86px;
    height: 32px;
    background-image: url("assets/svg/rss.svg");
    background-size: contain;
    background-repeat: no-repeat;
    background-position: left center;
    padding-right: 111px;
}

.rss-year {
    position: absolute;
    bottom: 0;
    right: 0;
    font-size: 21px;
    letter-spacing: -2px;
    color: #cbd5de;
    line-height: 0.9;
    font-weight: bold;
    transition: 0.3s;
}

.rss:hover .rss-year {
    right: -5px;
    letter-spacing: 0;
}

@media (max-width: 768px) {
    .fullscreen {
        top: 10px;
        right: 20px;
        width: 40px;
        height: 40px;
    }
}

@media (max-width: 600px) {
    .main {
        padding-top: 40px;
    }
    .piano {
        width: 310px;
        height: 160px;
    }
    .piano-key {
        width: 44px;
        height: 160px;
        border-radius: 0px 0px 8px 8px;
        border: 2px solid #313940;
    }
    .keys-sharp {
        left: 26px;
        right: 26px;
    }
    .piano-key.sharp {
        width: 36px;
        height: 100px;
        border-radius: 0px 0px 6px 6px;
    }
    .piano-key::before,
    .piano-key::after {
        width: 30px;
        height: 30px;
        font-size: 22px;
        bottom: -35px;
        left: 7px;
        font-size: 22px;
    }
    .piano-key.sharp::before,
    .piano-key.sharp::after {
        bottom: 115px;
        left: 3px;
    }
    .btn-container {
        width: 244px;
        height: 40px;
        margin-bottom: 80px;
    }
    .btn {
        width: 120px;
        height: 40px;
    }
}