input {
    max-width: 100%;
    font-size: 16px;
    padding: 5px;
    border: none;
    outline: 3px solid #ccc;
    -webkit-transition: outline 300ms ease-out;
    -moz-transition: outline 300ms ease-out;
    -o-transition: outline 300ms ease-out;
    transition: outline 300ms ease-out;
    box-sizing: border-box;
}
input {
    display: inline-block;
}
.speeds input {
    width: 60px;
}
.speeds {
    display: flex;
    justify-content: space-between;
}
h2 {
    font-size: 15px;
    margin: 20px 0 5px;
}
h3 {
    margin-bottom: 7px;
    font-size: 16px;
}
.hideit {
    display: none;
}

label {
    margin: 30px 0 10px;
    display: inline-block;
}
.small {
    font-size: 12px;
}
.hey1 label,
.hey2 .speeds label,
.hey {
    color: #cb4e4e;
    font-weight: bold;
}
.hey1 input:focus,
.hey2 .speeds input,
.hey2 .speeds input:focus {
    outline: 3px solid #cb4e4e;
}
input:focus {
    outline: 3px solid #24a777;
}
.hey > p {
    display: none;
    font-size: 15px;
}
.hey1 .hey > p:nth-child(1),
.hey2 .hey > p:nth-child(2) {
    display: block;
    margin: 20px 0;
}
.graphic {
    position: relative;
    margin: 20px;
    height: 60px;
    width: calc(100% - 40px);
    border-bottom: 1px solid #2583bd;
}
.achilles,
.turtle,
.both {
    display: block;
    background-repeat: no-repeat;
    background-position: center;
    position: absolute;
    bottom: 0;
    transform: translateX(-50%);
    background-size: contain;
}
.achilles {
    background-image: url("achilles.png");
    width: 50px;
    height: 65px;
    left: 0;
    z-index: 999;
}
.turtle {
    background-image: url("turtle.png");
    width: 20px;
    height: 10px;
    left: 80%;
    z-index: 999;
}
.both {
    background-image: url("both.png");
    width: 50px;
    height: 65px;
    left: 100%;
    opacity: 0;
    z-index: 999;
}

/* Animation classes */
.animate-achilles {
    animation: achilles-movement var(--animation-duration, 5s) forwards ease-out;
}

.animate-turtle {
    animation: turtle-movement var(--animation-duration, 5s) forwards linear;
}

.animate-both {
    animation: fade-in 0.5s forwards;
    animation-delay: var(--animation-duration, 5s);
}

/* Zeno's paradox animations */
@keyframes achilles-movement {
    0% {
        left: 0;
    }
    50% {
        left: 50%;
    }
    75% {
        left: 75%;
    }
    93% {
        left: 93%;
    }
    97% {
        left: 97%;
    }
    98% {
        left: 98%;
    }
    99% {
        left: 99%;
    }
    100% {
        left: 100%;
    }
}

@keyframes turtle-movement {
    0% {
        left: 80%;
    }
    100% {
        left: 100%;
    }
}

@keyframes fade-in {
    0% {
        opacity: 0;
    }
    100% {
        opacity: 1;
    }
}

/* Controls for animation */
.animation-controls {
    margin: 20px 0;
    text-align: center;
}

.btn {
    background-color: #2583bd;
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

.btn:hover {
    background-color: #1c6999;
}

.btn:disabled {
    background-color: #ccc;
    cursor: not-allowed;
}

span[class^="point"] {
    display: block;
    width: 1px;
    height: 10px;
    position: absolute;
    bottom: -10px;
    background-color: #2583bd;
}
.point1 {
    left: 0;
}
.point2 {
    left: 80%;
    transition: left 500ms ease-out;
}
.point3 {
    left: 100%;
}
div[class$="-output"] > p {
    display: inline-block;
    border-bottom: 3px solid #24a777;
    padding-bottom: 2px;
}

.animation-progress {
    width: 100%;
    height: 5px;
    background-color: #eee;
    margin-top: 10px;
    position: relative;
}

.animation-progress-bar {
    height: 100%;
    width: 0;
    background-color: #24a777;
    transition: width 0.1s linear;
}

.path-markers {
    position: absolute;
    top: -15px;
    width: 100%;
    display: flex;
    justify-content: space-between;
    font-size: 10px;
    color: #666;
}

@media (max-width: 580px) {
    .speeds {
        display: block;
    }
}