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

:root {
    --hue: 223;
    --white: hsl(var(--hue), 10%, 100%);
    --lt-gray: hsl(var(--hue), 10%, 95%);
    --gray1: hsl(var(--hue), 10%, 90%);
    --gray2: hsl(var(--hue), 10%, 80%);
    --gray7: hsl(var(--hue), 10%, 30%);
    --gray9: hsl(var(--hue), 10%, 10%);
    --primary: hsl(var(--hue), 90%, 55%);
    --trans-dur: 0.3s;
    font-size: calc(16px + (24 - 16) * (100vw - 320px) / (1280 - 320));
}

body,
input {
    font: 1em/1.5 "DM Sans", sans-serif;
}

body {
    background-color: var(--white);
    color: var(--gray9);
    height: 100vh;
    display: grid;
    place-items: center;
    transition:
        background-color var(--trans-dur),
        color var(--trans-dur);
}

/* Main styles */
.fr {
    animation: fade-slide-in 0.6s ease-out;
    padding: 0 1.5em;
    max-width: 20em;
}

.fr__face {
    --face-hue1: 60;
    --face-hue2: 30;
    background-image:
        linear-gradient(135deg,
            hsl(var(--face-hue1), 90%, 55%),
            hsl(var(--face-hue2), 90%, 45%));
    border-radius: 50%;
    box-shadow: 0 0.5em 0.75em hsla(var(--face-hue2), 90%, 55%, 0.3);
    margin: 0 auto 2em;
    position: relative;
    width: 3em;
    height: 3em;
}

.fr__face-right-eye,
.fr__face-left-eye,
.fr__face-mouth-lower,
.fr__face-mouth-upper {
    position: absolute;
    transition:
        background-color var(--trans-dur),
        box-shadow var(--trans-dur),
        color var(--trans-dur);
}

.fr__face-right-eye,
.fr__face-left-eye {
    background-color: var(--white);
    border-radius: 50%;
    top: 0.75em;
    width: 0.6em;
    height: 0.6em;
}

.fr__face-right-eye {
    --delay-right: 0s;
    animation: right-eye 1s var(--delay-right) linear paused;
    clip-path: polygon(0 75%, 100% 0, 100% 100%, 0 100%);
    left: 0.6em;
}

.fr__face-left-eye {
    --delay-left: 0s;
    animation: left-eye 1s var(--delay-left) linear paused;
    clip-path: polygon(0 0, 100% 75%, 100% 100%, 0 100%);
    right: 0.6em;
}

.fr__face-mouth-lower,
.fr__face-mouth-upper {
    color: var(--white);
    top: 1.75em;
    left: 0.75em;
    width: 1.5em;
    height: 0.75em;
}

.fr__face-mouth-lower {
    --delay-mouth-lower: 0s;
    animation: mouth-lower 1s var(--delay-mouth-lower) linear paused;
    border-radius: 50% 50% 0 0 / 100% 100% 0 0;
    box-shadow: 0 0.125em 0 inset;
}

.fr__face-mouth-upper {
    --delay-mouth-upper: 0s;
    animation: mouth-upper 1s var(--delay-mouth-upper) linear paused;
    border-radius: 0 0 50% 50% / 0 0 100% 100%;
    box-shadow: 0 -0.125em 0 inset;
}

.fr__label {
    display: block;
    margin-bottom: 1.5em;
    text-align: center;
}

.fr__input {
    --input-hue: 60;
    --percent: 50%;
    background-color: var(--gray1);
    background-image: linear-gradient(hsl(var(--input-hue), 90%, 45%), hsl(var(--input-hue), 90%, 45%));
    background-size: var(--percent) 100%;
    background-repeat: no-repeat;
    border-radius: 0.25em;
    display: block;
    margin: 0.5em auto;
    width: 100%;
    max-width: 10em;
    height: 0.5em;
    transition: background-color var(--trans-dur);
    -webkit-appearance: none;
    appearance: none;
    -webkit-tap-highlight-color: transparent;
}

.fr__input:focus {
    outline: transparent;
}

/* WebKit */
.fr__input::-webkit-slider-thumb {
    background-color: var(--white);
    border: 0;
    border-radius: 50%;
    box-shadow: 0 0.125em 0.5em hsl(0, 0%, 0%, 0.3);
    width: 0.5em;
    height: 0.5em;
    transition: background-color 0.15s linear;
    -webkit-appearance: none;
    appearance: none;
    display: none !important;
}

.fr__input:focus::-webkit-slider-thumb,
.fr__input::-webkit-slider-thumb:hover {
    background-color: var(--lt-gray);
}

.fr__input:focus::-moz-range-thumb,
.fr__input::-moz-range-thumb:hover {
    background-color: var(--lt-gray);
}

/* `:focus-visible` support */
@supports selector(:focus-visible) {
    .fr__input:focus::-webkit-slider-thumb {
        background-color: var(--white);
    }

    .fr__input:focus-visible::-webkit-slider-thumb,
    .fr__input::-webkit-slider-thumb:hover {
        background-color: var(--lt-gray);
    }

    .fr__input:focus::-moz-range-thumb {
        background-color: var(--white);
    }

    .fr__input:focus-visible::-moz-range-thumb,
    .fr__input::-moz-range-thumb:hover {
        background-color: var(--lt-gray);
    }
}

/* Animations */
@keyframes fade-slide-in {

    from,
    16.67% {
        opacity: 0;
        transform: translateY(25%);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes right-eye {
    from {
        clip-path: polygon(0 75%, 100% 0, 100% 100%, 0 100%);
    }

    50%,
    to {
        clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
    }
}

@keyframes left-eye {
    from {
        clip-path: polygon(0 0, 100% 75%, 100% 100%, 0 100%);
    }

    50%,
    to {
        clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
    }
}

@keyframes mouth-lower {
    from {
        border-radius: 50% 50% 0 0 / 100% 100% 0 0;
        top: 1.75em;
        height: 0.75em;
        visibility: visible;
    }

    40% {
        border-radius: 50% 50% 0 0 / 100% 100% 0 0;
        top: 1.95em;
        height: 0.25em;
        visibility: visible;
    }

    50%,
    to {
        border-radius: 0;
        top: 2em;
        height: 0.125em;
        visibility: hidden;
    }
}

@keyframes mouth-upper {

    from,
    50% {
        border-radius: 0;
        box-shadow: 0 -0.125em 0 inset;
        top: 2em;
        height: 0.125em;
        visibility: hidden;
    }

    62.5% {
        border-radius: 0 0 50% 50% / 0 0 100% 100%;
        box-shadow: 0 -0.125em 0 inset;
        top: 1.95em;
        height: 0.25em;
        visibility: visible;
    }

    75% {
        border-radius: 0 0 50% 50% / 0 0 100% 100%;
        box-shadow: 0 -0.125em 0 inset;
        top: 1.825em;
        height: 0.5em;
        visibility: visible;
    }

    to {
        border-radius: 0 0 50% 50% / 0 0 100% 100%;
        box-shadow: 0 -0.8em 0 inset;
        top: 1.75em;
        height: 0.75em;
        visibility: visible;
    }
}