/* ========================================
   Design tokens
======================================== */

:root {
    color-scheme: dark;

    --color-background: #090c09;
    --color-surface: #101610;
    --color-surface-hover: #172017;

    --color-text: #f0f5ee;
    --color-muted: #b5beb2;
    --color-subtle: #858f82;

    --color-border: #293329;
    --color-border-strong: #465446;

    --color-primary: #9bdc65;
    --color-primary-hover: #b8ee8a;
    --color-primary-muted: #72a94c;
    --color-primary-surface: #172515;
    --color-on-primary: #091008;

    --color-error: #f0a5b5;

    --font-body:
        system-ui,
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        sans-serif;

    --font-mono:
        ui-monospace,
        SFMono-Regular,
        Menlo,
        Monaco,
        Consolas,
        "Liberation Mono",
        monospace;

    --content-width: 74rem;
    --page-padding: 1.5rem;
    --section-spacing: clamp(4.5rem, 9vw, 7rem);
}


/* ========================================
   Reset
======================================== */

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

html {
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    margin: 0;

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

    color: var(--color-text);
    background-color: var(--color-background);

    font-family: var(--font-body);
    font-size: 1.0625rem;
    font-weight: 400;
    line-height: 1.75;

    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

img,
svg {
    display: block;
    max-width: 100%;
}

ul,
ol {
    margin: 0;
    padding: 0;
}

a {
    color: inherit;
    text-decoration: none;
}

button,
input,
textarea {
    color: inherit;
    font: inherit;
}

button {
    border: 0;
}

[hidden] {
    display: none !important;
}

::selection {
    color: var(--color-on-primary);
    background-color: var(--color-primary);
}


/* ========================================
 =================================   Accessibility
======================================== */

.skip-link {
    position: fixed;
    top: 1rem;
    left: 1rem;
    z-index: 100;

    padding: 0.65rem 1rem;

    color: var(--color-on-primary);
    background-color: var(--color-primary);

    font-weight: 600;

    transform: translateY(-200%);
    transition: transform 150ms ease;
}

.skip-link:focus {
    transform: translateY(0);
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 4px;
}


/* ========================================
   Shared layout
======================================== */

.site-header,
main,
.site-footer {
    width: min(
        calc(100% - (var(--page-padding) * 2)),
        var(--content-width)
    );

    margin-inline: auto;
}

section {
    padding-block: var(--section-spacing);
    border-top: 1px solid var(--color-border);
}

section:first-child {
    border-top: 0;
}

h1,
h2,
h3,
.command,
.site-header,
.engineering-principles,
.project-filter,
.view-projects-link,
.project-card header,
.project-tags,
.project-learning strong,
.contact-email,
.site-footer,
.project-message,
.content-message,
.noscript-message {
    font-family: var(--font-mono);
}

.project-message,
.content-message {
    font-size: 0.9rem;
}

h1,
h2,
h3,
p {
    margin-top: 0;
}

h1,
h2,
h3 {
    color: var(--color-text);

    font-weight: 500;
    line-height: 1.2;
    letter-spacing: -0.025em;

    text-wrap: balance;
}

h1 {
    max-width: 18ch;
    margin-bottom: 1.75rem;

    font-size: clamp(2.65rem, 6vw, 4.75rem);
}

h2 {
    margin-bottom: 1.5rem;

    font-size: clamp(1.85rem, 4vw, 2.65rem);
}

h3 {
    font-size: 1.2rem;
}

p {
    max-width: 65ch;
    text-wrap: pretty;
}

.command {
    margin-bottom: 1.15rem;

    color: var(--color-primary);

    font-size: 0.95rem;
    font-weight: 500;
    letter-spacing: 0.015em;
}


/* ========================================
   Header
======================================== */

.site-header {
    min-height: 5rem;

    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;

    border-bottom: 1px solid var(--color-border);
}

.site-identity {
    display: inline-flex;
    align-items: center;
    gap: 0.65rem;

    font-size: 1rem;
    font-weight: 500;
}

.site-identity span:first-child {
    color: var(--color-primary);
}

.site-identity span:last-child {
    color: var(--color-subtle);
    font-size: 0.825rem;
}

.site-identity:hover span:first-child {
    color: var(--color-primary-hover);
}

.navigation-list {
    display: flex;
    align-items: center;
    gap: clamp(1rem, 3vw, 2rem);

    color: var(--color-muted);
    font-size: 0.925rem;

    list-style: none;
}

.navigation-list a,
.navigation-pending {
    display: inline-block;
    padding-block: 0.5rem;
}

.navigation-list a {
    transition: color 150ms ease;
}

.navigation-list a:hover {
    color: var(--color-text);
}

.navigation-list a[aria-current="page"] {
    color: var(--color-primary);
}

.navigation-list a[aria-current="page"]::before {
    content: "> ";
}

.navigation-pending {
    color: var(--color-subtle);
    cursor: default;
}

.navigation-pending::after {
    content: "*";
    color: var(--color-primary-muted);
}


/* ========================================
   Hero
======================================== */

.hero-section {
    min-height: 38rem;

    display: grid;
    grid-template-columns:
        minmax(0, 1.5fr)
        minmax(15rem, 0.65fr);
    align-content: center;
    align-items: end;
    gap: clamp(3rem, 8vw, 7rem);
}

.hero-content p {
    margin-bottom: 0;

    color: var(--color-muted);

    font-size: clamp(1.075rem, 2vw, 1.2rem);
    line-height: 1.85;
}

.hero-content::after {
    content: "";

    display: block;
    width: 0.7rem;
    height: 1.15rem;
    margin-top: 1.25rem;

    background-color: var(--color-primary);
}

.engineering-principles {
    padding-left: 1.5rem;
    border-left: 2px solid var(--color-primary-muted);
}

.engineering-principles ol {
    display: grid;
    gap: 0.9rem;

    color: var(--color-muted);
    font-size: 0.95rem;
    line-height: 1.7;

    counter-reset: engineering-value;
}

.engineering-principles li {
    display: grid;
    grid-template-columns: 2rem 1fr;
    gap: 0.25rem;

    list-style: none;

    counter-increment: engineering-value;
}

.engineering-principles li::before {
    content: "0" counter(engineering-value);

    color: var(--color-primary);
}


/* ========================================
   Section header
======================================== */

.section-header {
    margin-bottom: 2.5rem;

    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 2rem;
}

.section-header h2 {
    margin-bottom: 0;
}

.project-section-actions {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 1rem;
    flex-wrap: wrap;
}

.view-projects-link {
    color: var(--color-primary);

    font-size: 0.9rem;
    white-space: nowrap;
}

.view-projects-link:hover {
    color: var(--color-primary-hover);
    text-decoration: underline;
    text-underline-offset: 0.35rem;
}


/* ========================================
   Project filters
======================================== */

.project-filters {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.project-filter {
    padding: 0.55rem 0.9rem;

    color: var(--color-muted);
    background-color: var(--color-surface);
    border: 1px solid var(--color-border);

    border-radius: 100rem;

    font-size: 0.9rem;
    line-height: 1;

    cursor: pointer;

    transition:
        color 150ms ease,
        background-color 150ms ease,
        border-color 150ms ease;
}

.project-filter:hover {
    color: var(--color-text);
    background-color: var(--color-surface-hover);
    border-color: var(--color-border-strong);
}

.project-filter[aria-pressed="true"],
.project-filter-active {
    color: var(--color-on-primary);
    background-color: var(--color-primary);
    border-color: var(--color-primary);
}

.project-filter[aria-pressed="true"]:hover,
.project-filter-active:hover {
    color: var(--color-on-primary);
    background-color: var(--color-primary);
    border-color: var(--color-primary);
}


/* ========================================
   Project cards
======================================== */

.project-list {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));

    background-color: var(--color-border);
    border: 1px solid var(--color-border);

    gap: 1px;
}

.project-card {
    min-width: 0;
    min-height: 21rem;
    padding: 1.75rem;

    display: flex;
    flex-direction: column;

    color: var(--color-text);
    background-color: var(--color-background);

    transition: background-color 150ms ease;
}

.project-card:hover {
    background-color: var(--color-surface);
}

.project-card:focus-visible {
    position: relative;
    z-index: 1;

    outline-offset: -3px;
}

.project-card header {
    margin-bottom: 1.25rem;

    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;

    color: var(--color-subtle);

    font-size: 0.825rem;
}

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

.project-card h3 {
    margin-bottom: 0.75rem;

    transition: color 150ms ease;
}

.project-card:hover h3 {
    color: var(--color-primary);
}

.project-card h3::after {
    content: " ↗";

    color: var(--color-primary);
    font-size: 0.75em;

    opacity: 0;
    transition: opacity 150ms ease;
}

.project-card:hover h3::after,
.project-card:focus-visible h3::after {
    opacity: 1;
}

.project-description {
    margin-bottom: 1.2rem;

    color: var(--color-muted);
    font-size: 1rem;
    line-height: 1.75;
}

.project-learning {
    margin-bottom: 1.5rem;
    padding-top: 1rem;

    color: var(--color-muted);
    border-top: 1px solid var(--color-border);

    font-size: 0.925rem;
    line-height: 1.7;
}

.project-learning strong {
    color: var(--color-primary);

    font-weight: 500;
}

.project-tags {
    margin-top: auto;

    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;

    list-style: none;
}

.project-tags li {
    padding: 0.22rem 0.5rem;

    color: var(--color-primary);
    background-color: var(--color-primary-surface);

    font-size: 0.8rem;
    line-height: 1.4;
}


/* ========================================
   Loading and error states
======================================== */

.project-message,
.content-message {
    margin: 0;
    padding: 2rem;

    color: var(--color-subtle);

    font-size: 0.825rem;
}

.project-message {
    grid-column: 1 / -1;
    background-color: var(--color-background);
}

.project-error {
    color: var(--color-error);
}

.noscript-message {
    position: fixed;
    right: 1rem;
    bottom: 1rem;
    z-index: 20;

    margin: 0;
    padding: 0.75rem 1rem;

    color: var(--color-on-primary);
    background-color: var(--color-primary);

    font-size: 0.8rem;
}


/* ========================================
   How I work
======================================== */

.principle-list {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));

    background-color: var(--color-border);
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);

    gap: 1px;
}

.principle {
    min-width: 0;
    padding: 1.75rem;

    background-color: var(--color-background);
}

.principle h3 {
    margin-bottom: 0.75rem;

    font-size: 1.1rem;
}

.principle p {
    margin-bottom: 0;

    color: var(--color-muted);

    font-size: 0.975rem;
    line-height: 1.75;
}


/* ========================================
   Contact
======================================== */

.contact-section {
    min-height: 25rem;

    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
}

.contact-section h2 {
    max-width: 22ch;
}

.contact-section p:not(.command) {
    margin-bottom: 0;

    color: var(--color-muted);
}

.contact-email {
    margin-top: 1.5rem;
    padding: 0.65rem 0.9rem;

    display: inline-flex;
    align-items: center;

    color: var(--color-primary);
    background-color: var(--color-primary-surface);
    border: 1px solid var(--color-primary-muted);

    font-size: 0.925rem;

    transition:
        color 150ms ease,
        background-color 150ms ease,
        border-color 150ms ease;
}

.contact-email::before {
    content: "> ";
    margin-right: 0.5rem;
}

.contact-email:hover {
    color: var(--color-on-primary);
    background-color: var(--color-primary);
    border-color: var(--color-primary);
}


/* ========================================
   Footer
======================================== */

.site-footer {
    min-height: 6rem;

    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;

    color: var(--color-subtle);
    border-top: 1px solid var(--color-border);

    font-size: 0.875rem;
}

.site-footer p {
    margin: 0;
}

#availability-status[data-available="true"]::before {
    content: "";

    display: inline-block;
    width: 0.45rem;
    height: 0.45rem;
    margin-right: 0.6rem;

    background-color: var(--color-primary);
    border-radius: 50%;
}

.footer-links {
    display: flex;
    align-items: center;
    flex-wrap: wrap;

    list-style: none;
}

.footer-links li + li::before {
    content: "·";

    margin-inline: 0.65rem;

    color: var(--color-primary-muted);
}

.footer-links a {
    color: var(--color-muted);

    transition: color 150ms ease;
}

.footer-links a:hover {
    color: var(--color-primary);
}


/* ========================================
   Tablet
======================================== */

@media (max-width: 60rem) {
    .hero-section {
        min-height: auto;

        grid-template-columns: 1fr;
        align-items: start;
        gap: 3rem;
    }

    .engineering-principles {
        width: min(100%, 28rem);
    }

    .project-list {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .principle-list {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}


/* ========================================
   Mobile
======================================== */

@media (max-width: 42rem) {
    :root {
        --page-padding: 1rem;
        --section-spacing: 4rem;
    }

    .site-header {
        padding-block: 1rem;

        align-items: flex-start;
        flex-direction: column;
        gap: 0.5rem;
    }

    .navigation-list {
        width: 100%;
        gap: 1rem;

        overflow-x: auto;
        scrollbar-width: none;
    }

    .navigation-list::-webkit-scrollbar {
        display: none;
    }

    h1 {
        font-size: clamp(2.1rem, 11vw, 3rem);
    }

    .section-header {
        align-items: flex-start;
        flex-direction: column;
        gap: 1.25rem;
    }

    .project-section-actions {
        width: 100%;

        justify-content: space-between;
    }

    .project-list {
        grid-template-columns: 1fr;
    }

    .project-card {
        min-height: 0;
    }

    .principle-list {
        grid-template-columns: 1fr;
    }

    .contact-section {
        min-height: 22rem;
    }

    .site-footer {
        padding-block: 1.5rem;

        align-items: flex-start;
        flex-direction: column;
        gap: 0.75rem;
    }
}


/* ========================================
   Small mobile
======================================== */

@media (max-width: 28rem) {
    .project-section-actions {
        align-items: flex-start;
        flex-direction: column;
    }

    .project-filter {
        padding-inline: 0.75rem;
    }

    .footer-links li + li::before {
        margin-inline: 0.4rem;
    }
}


/* ========================================
   Reduced motion
======================================== */

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
}