$device-s-width: 640px;
$device-m-width: 1200px;

:root {
    --accent: #7b3a99;
}

// Normalize

*,
*::before,
*::after {
    box-sizing: border-box;
}

html,
body {
    width: 100%;
    height: 100%;
    min-height: 100%;
    margin: 0;

    font-family: 'Lato', sans-serif;
    font-weight: 300;
    font-size: 18px;

    line-height: 1;
}

textarea {
    border: none;
    outline: gray;

    width: 100%;

    padding: 1rem;

    box-shadow: -2px 4px 6px 1px #00000018, 0 0 4px 0px #00000010;
    border-radius: 0.25rem;
    background: #ffffff;
}

label {
    font-weight: 400;
}

input[type='text'] {
    border: none;
    outline: gray;

    width: 100%;

    padding: 0.5rem;

    box-shadow: -2px 4px 4px 0 #00000010;
    border-radius: 0.25rem;
    background: #ffffff;

    font-family: 'Lato';
    font-weight: 400;
    font-size: 16px;
    color: #555;
}

.input-select {
    display: inline-flex;
    align-items: center;
    justify-content: space-between;

    cursor: pointer;
    font-family: 'Lato';
    font-weight: 600;
    font-size: 16px;
    color: #555;

    border: 1px solid #c8c8c8;
    padding: 0;
    margin: 0;

    box-shadow: -2px 2px 16px 0 #00000010;
    border-radius: 0.25rem;

    background: linear-gradient(180deg, #f0f0f0, #e8e8e8 20%, #e0e0e0 90%, #cdcdcd);

    &:hover {
        border: 1px solid #c4c4c4;
        box-shadow: -2px 2px 20px 0 #00000010;
        background: linear-gradient(180deg, #fff, #ededed 20%, #e8e8e8 90%, #c0c0c0);
    }

    select {
        cursor: pointer;
        height: 100%;

        appearance: none;

        transform: translate(0, -0.0625rem);

        padding: 0.35rem 0 0.35rem 0.35rem;
        margin: 0;
        border: none;
        outline: none;
        background: none;

        font-family: 'Lato';
        font-weight: 600;
        font-size: 16px;
        color: #555;
    }

    .material-symbols-outlined {
        display: grid;
        place-content: center;

        width: 1.75rem;
        height: 1.75rem;

        transform: translate(0, 0.0625rem);
    }
}

button {
    cursor: pointer;

    font-family: 'Lato';
    font-weight: 600;
    font-size: 16px;
    color: #555;

    border: 1px solid #c8c8c8;
    padding: 0.5rem 2rem;

    box-shadow: -2px 2px 16px 0 #00000010;
    border-radius: 0.25rem;

    background: linear-gradient(180deg, #f0f0f0, #e8e8e8 20%, #e0e0e0 90%, #cdcdcd);

    transition: all 100ms ease-in;

    &:hover {
        border: 1px solid #c4c4c4;
        box-shadow: -2px 2px 20px 0 #00000010;
        background: linear-gradient(180deg, #fff, #ededed 20%, #e8e8e8 90%, #c0c0c0);
    }

    &.compact {
        padding: 0.35rem;
        font-size: 15px;
    }

    &:disabled {
        cursor: default;
        opacity: 0.6;

        filter: grayscale(1);

        &:hover {
            border: 1px solid #c8c8c8;
            box-shadow: -2px 2px 16px 0 #00000010;
            background: linear-gradient(180deg, #f0f0f0, #e8e8e8 20%, #e0e0e0 90%, #cdcdcd);
        }
    }

    &.icon {
        padding: 0.125rem;
        display: grid;
        place-content: center;

        .material-symbols-outlined {
            font-size: 19px;
        }
    }
}

.link,
a,
a:visited {
    cursor: pointer;

    color: var(--accent);
    text-decoration: none;

    &:hover {
        text-decoration: underline;
    }
}

//
// Typography
//

.dotted {
    text-decoration: underline dotted gray;
}

.math-inline {
    font-size: 95%;
}

p {
    margin: 0;
}

p + p {
    margin-top: 0.5rem;
}

$base-font-size: 16px;
$heading-scale: 1.25;

@function pow($number, $exponent) {
    $value: 1;

    @if $exponent > 0 {
        @for $i from 1 through $exponent {
            $value: $value * $number;
        }
    }

    @return $value;
}

@for $i from 1 through 4 {
    h#{$i} {
        margin: 0;

        $factor: pow($heading-scale, 4 - $i);
        font-size: $base-font-size * $factor;
        font-weight: 500;

        &:not(:first-child) {
            padding-top: 0.5rem * $factor;
        }

        line-height: 1;
    }
}

//
// Components
//

.text-body {
    font-family: 'EB Garamond', serif;
    font-weight: 400;
    font-size: 18px;

    line-height: 1.41;

    b,
    strong {
        font-weight: 600;
    }
}

//
// Structure
//

body {
    display: flex;
    flex-direction: column;
    align-items: center;

    background: #f8f8f8;
}

main {
    padding: 2rem 2rem 6rem;
    width: 100%;

    display: flex;
    flex-direction: column;
    align-items: center;

    gap: 2rem;

    .subtitle {
        font-size: 22px;
    }

    .fill-main {
        display: flex;
        gap: 0.5rem;

        width: 100%;
        max-width: 80ch;
    }
}

main.page-home {
    .board {
        width: 100%;
        // min-width: 0;

        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(auto, 70ch));
        gap: 2rem;

        justify-content: center;

        .fill-row {
            grid-column: 1 / -1;
        }

        .board-controls {
            justify-self: start;
        }
    }
}

main.page-problem {
    summary {
        padding: 1rem;
        text-align: center;

        user-select: none;
    }
}

//
// Components
//

details {
    width: 100%;
    max-width: 80ch;
}

.solution-list {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;

    .controls {
        display: flex;
        width: 100%;
        gap: 1rem;
    }
}

header {
    display: grid;
    place-content: center;

    width: 100%;
    position: relative;

    .logo {
        font-size: 42px;
        font-family: 'Lato';
        font-weight: 300;

        a:hover {
            text-decoration: none;
            border-bottom: 3px solid var(--accent);
        }
    }

    nav {
        position: absolute;
        right: 0;

        display: flex;
        gap: 1rem;

        height: 100%;
        align-items: center;

        .nav-item {
            font-size: 20px;
            font-weight: 300;

            a.active {
                border-bottom: 1px solid var(--accent);
            }

            a:hover {
                text-decoration: none;
                border-bottom: 2px solid var(--accent);
            }
        }
    }
}

.problem {
    padding: 1rem;

    max-width: 80ch;

    box-shadow: -2px 4px 6px 1px #00000018, 0 0 4px 0px #00000010;
    border-radius: 0.5rem;
    background: #ffffff;

    display: flex;
    flex-direction: column;
    gap: 0.5rem;

    .problem-header {
        display: grid;
        grid-template-columns: auto;
        gap: 0.25rem;

        .problem-title {
            font-size: 22px;
            font-weight: 400;
        }
    }

    .problem-content {
        @extend .text-body;
    }

    .problem-footer {
        font-size: 16px;
    }
}

.solution {
    padding: 1rem 0.5rem 0.5rem 1rem;

    width: 100%;
    max-width: 80ch;

    box-shadow: -2px 4px 6px 1px #00000018, 0 0 4px 0px #00000010;
    border-radius: 0.5rem;
    background: #ffffff;

    display: flex;
    flex-direction: column;
    gap: 0.5rem;

    transition: all 100ms ease-in-out;

    &.correct {
        border: 4px solid #00aa00;
    }
    &.wrong {
        border: 4px solid #cc0000;
    }

    .solution-header {
        display: grid;
        grid-template-columns: auto;
        gap: 0.25rem;

        font-size: 18px;

        line-height: 1.25;
    }

    .solution-content {
        @extend .text-body;

        pre,
        code {
            margin: 0;
            font-family: 'DM Mono', monospace;
            font-size: 16px;

            background: #f0f0f0;
        }

        pre {
            padding: 0.25rem;
            overflow-x: auto;

            border-radius: 0.25rem;

            white-space: break-spaces;
        }

        padding-right: 0.5rem;
    }

    .solution-footer {
        display: flex;
        justify-content: end;

        font-size: 16px;

        .label {
            font-weight: 400;
        }

        .row {
            display: flex;
            gap: 0.5rem;
            align-items: center;
        }

        .pending {
            color: #1653a3;
            font-style: italic;
        }
        .correct {
            color: green;
            // font-weight: 400;
        }
        .wrong {
            color: darkred;
            // font-weight: 400;
        }

        .status-label {
            text-align: right;
        }
    }
}

.form {
    min-width: 50ch;

    background: #e0e0e0;

    display: grid;
    grid-template-columns: auto 1fr;

    border: 1px solid #c0c0c0;
    border-radius: 1rem;

    // box-shadow: -2px 4px 16px 4px #00000018, -2px 4px 4px 1px #00000018;

    padding: 1.5rem 2rem 1rem;
    gap: 1rem;

    align-items: center;

    .fill {
        grid-column: span 2;
        justify-self: center;
    }
}

.markdown-editor {
    display: grid;
    width: 100%;
    grid-template-columns: repeat(2, 1fr);

    gap: 1rem;

    .editor,
    .preview {
        width: 100%;
        max-width: 70ch;

        display: flex;
        flex-direction: column;
        align-items: center;

        gap: 1rem;
    }

    .editor {
        justify-self: end;

        textarea {
            font-family: 'DM Mono', monospace;
            font-size: 16px;

            resize: none;
            overflow-y: hidden;

            min-height: 8rem;
        }
    }

    .preview {
        justify-self: start;

        .placeholder {
            color: #666;
        }

        .preview-content {
            @extend .text-body;

            width: 100%;

            padding: 1rem;

            box-shadow: -2px 4px 6px 1px #00000018, 0 0 4px 0px #00000010;
            border-radius: 0.25rem;
            background: #ffffff;
        }
    }
}

//
// Mobile
//

// Not on mobile
@media screen and (min-width: $device-s-width) and (pointer: fine) {
    // ...
}

// On mobile
@media screen and (max-width: $device-s-width), (pointer: coarse) {
    main {
        padding: 1rem 1rem 6rem;

        &.page-home {
            .board {
                gap: 1rem;
            }
        }
    }

    header {
        display: flex;
        flex-direction: column;
        align-items: center;

        gap: 2rem;

        nav {
            position: relative;
            right: unset;

            display: flex;
            flex-direction: column;
            align-items: center;
        }
    }

    .problem {
        padding: 0.75rem;
    }

    .markdown-editor {
        grid-template-columns: auto;
        grid-template-rows: auto auto;
    }

    .form {
        width: 100%;
        padding: 1rem;

        min-width: unset;

        display: flex;
        flex-direction: column;

        label {
            align-self: start;
        }
    }

    textarea,
    .markdown-editor .preview .preview-content {
        padding: 0.75rem;
    }

    .solution {
        .solution-content {
            pre {
                white-space: pre-line;
                word-break: break-all;
            }
        }
    }
}

@media screen and (max-width: $device-m-width), (pointer: coarse) {
    .markdown-editor {
        grid-template-columns: auto;
        grid-template-rows: auto auto;

        .preview,
        .editor {
            justify-self: center;
        }
    }
}