:root {
    /* Colors - OpenAI inspired palette */
    --bg-light: hsl(0 0% 100%);
    --bg-dark: hsl(0 0% 7%);
    --text-light: hsl(0 0% 7%);
    --text-dark: hsl(0 0% 95%);
    --muted-light: hsl(0 0% 40%);
    --muted-dark: hsl(0 0% 70%);
    --accent: hsl(0 0% 7%);
    --accent-hover: hsl(0 0% 20%);
    --border-light: hsl(0 0% 90%);
    --border-dark: hsl(0 0% 15%);
    --surface-light: hsl(0 0% 98%);
    --surface-dark: hsl(0 0% 10%);
    --white: hsl(0 0% 100%);

    /* Spacing - OpenAI's generous spacing system */
    --space-0: 0;
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;
    --space-32: 8rem;
    --space-40: 10rem;
    --space-48: 12rem;

    /* Typography - System font stack optimized for clarity */
    --font-sans:
        -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
        Arial, sans-serif;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    /* Font sizes - Progressive scale */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-md: 1.125rem;
    --text-lg: 1.25rem;
    --text-xl: 1.5rem;
    --text-2xl: 2rem;
    --text-3xl: 2.6rem;
    --text-4xl: 4rem;
    --text-5xl: 5rem;
    --text-6xl: 6rem;
    --text-7xl: 7rem;

    /* Line heights */
    --leading-none: 1;
    --leading-tight: 1.25;
    --leading-snug: 1.375;
    --leading-normal: 1.5;
    --leading-relaxed: 1.625;
    --leading-loose: 2;

    /* Layout */
    --container-max: 1200px;
    --container-narrow: 768px;
    --container-wide: 1400px;

    /* Transitions */
    --transition-all: all 0.2s ease-in-out;
    --transition-colors:
        color 0.2s ease-in-out, background-color 0.2s ease-in-out, border-color 0.2s ease-in-out;
}

@media (prefers-color-scheme: light) {
    :root {
        --bg: var(--bg-light);
        --text: var(--text-light);
        --muted: var(--muted-light);
        --border: var(--border-light);
        --surface: var(--surface-light);
    }
}

@media (prefers-color-scheme: light) {
    :root {
        --bg: var(--bg-light);
        --text: var(--text-light);
        --muted: var(--muted-light);
        --border: var(--border-light);
        --surface: var(--surface-light);
    }
    
    /* Make white logo black in light mode */
    .header__logo img {
        filter: invert(1);
    }
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: var(--bg-dark);
        --text: var(--text-dark);
        --muted: var(--muted-dark);
        --border: var(--border-dark);
        --surface: var(--surface-dark);
    }
    
    /* Logo stays white in dark mode (original color) */
    .header__logo img {
        filter: none;
    }
}

/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

body {
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: var(--leading-normal);
    color: var(--text);
    background-color: var(--bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    min-height: 100vh;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: var(--font-weight-semibold);
    line-height: var(--leading-tight);
    letter-spacing: -0.025em;
    text-wrap: balance;

}

p {
    line-height: var(--leading-relaxed);
    text-wrap: balance;
}

a {
    color: inherit;
    text-decoration: none;
    transition: var(--transition-colors);
}

/* Focus states */
a:focus-visible,
button:focus-visible,
[tabindex]:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
    border-radius: 0.125rem;
}

/* Layout utilities */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-6);
}

.container-narrow {
    max-width: var(--container-narrow);
    margin: 0 auto;
    padding: 0 var(--space-6);
}

.section {
    padding: var(--space-32) 0;
}

/* Header */
.header {
    position: sticky;
    top: 0;
    z-index: 50;
    background-color: var(--bg);
    backdrop-filter: blur(20px);
}

.header__container {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: var(--space-5) var(--space-6);
}

.header__logo {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    font-weight: var(--font-weight-semibold);
    font-size: var(--text-lg);
}

.header__logo img {
    height: 1.5rem;
    width: auto;
}

.nav__list {
    display: flex;
    gap: var(--space-8);
    list-style: none;
}

.nav__link {
    font-size: var(--text-sm);
    font-weight: var(--font-weight-medium);
    color: var(--muted);
    transition: var(--transition-colors);
}

.nav__link:hover {
    color: var(--text);
}

@media (max-width: 768px) {
    .nav__list {
        gap: var(--space-6);
    }
}

/* Hero section - OpenAI style */
.hero {
    position: relative;
    padding: var(--space-24) 0;
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    max-width: var(--container-max);
    margin: 0 auto;
}

.hero__container {
    position: relative;
    max-width: var(--container-max);
    padding: 0 var(--space-4);
    background: url("../assets/runway-hero.webp") no-repeat center center;
    background-size: cover;
    border-radius: 0.75rem;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
}

.hero__title {
    font-size: clamp(var(--text-4xl), 6vw, var(--text-7xl));
    font-weight: var(--font-weight-medium);
    line-height: var(--leading-none);
    margin-bottom: var(--space-8);
    letter-spacing: -0.02em;
    color: var(--white);
    text-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

.hero__description {
    font-size: var(--text-xl);
    color: var(--white);
    line-height: var(--leading-relaxed);
    max-width: 48rem;
    font-weight: var(--font-weight-semibold);
    margin: 0 auto;
    text-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
}

@media (max-width: 768px) {
    .hero {
        padding: 4vh var(--space-6);
    }

    .hero__container {
        min-height: 75vh;
    }

    .hero__title {
        margin-bottom: var(--space-6);
    }

    .hero__description {
        font-size: var(--text-lg);
    }
}

/* Ventures section */
.ventures {
    padding: var(--space-32) 0;
}

.ventures__container {
    text-align: center;
    margin-bottom: var(--space-20);
}

.ventures__title {
    font-size: clamp(var(--text-2xl), 6vw, var(--text-3xl));
    font-weight: var(--font-weight-medium);
    margin: 0 auto var(--space-6) auto;
    letter-spacing: -0.02em;
    max-width: 32ch;
}

.ventures__intro {
    font-size: var(--text-md);
    color: var(--muted);
    line-height: var(--leading-relaxed);
    margin: 0 auto;
    max-width: 44ch;
}

.ventures__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-4);
    margin-top: var(--space-16);
}

.venture-card {
    background-color: var(--bg);
    border: 1px solid var(--border);
    border-radius: 0.75rem;
    padding: var(--space-8);
    transition: var(--transition-all);
    text-align: left;
}

.venture-card:hover {
    border-color: var(--accent);
    transition: var(--transition-all);
    transform: translateY(-2px);
}

.venture-card__title {
    font-size: var(--text-xl);
    font-weight: var(--font-weight-medium);
    margin-bottom: var(--space-4);
    letter-spacing: -0.01em;
}

.venture-card__description {
    font-size: var(--text-base);
    color: var(--muted);
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-6);
}

.venture-card__status {
    display: inline-block;
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
    font-weight: var(--font-weight-medium);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: 9999px;
    margin-bottom: var(--space-4);
}

.venture-card__status--active {
    background-color: hsl(142 76% 36% / 0.1);
    color: #dd101f;
}

.venture-card__status--development {
    background-color: hsl(45 93% 47% / 0.1);
    color: #fc8c47;
}

.venture-card__link {
    display: inline-flex;
    align-items: center;
    margin-left: var(--space-2);
    gap: var(--space-2);
    font-size: var(--text-sm);
    font-weight: var(--font-weight-medium);
    color: var(--muted);
    transition: var(--transition-colors);
}

.venture-card__link:hover {
    color: var(--white);
}

.venture-card__link-icon {
    width: 1rem;
    height: 1rem;
}

@media (max-width: 768px) {
    .ventures__grid {
        grid-template-columns: 1fr;
        gap: var(--space-6);
    }
}

/* Philosophy section */
.philosophy {
    padding: var(--space-32) 0;
}

.philosophy__container {
    text-align: center;
    margin-bottom: var(--space-20);
}

.philosophy__title {
    font-size: clamp(var(--text-2xl), 6vw, var(--text-3xl));
    font-weight: var(--font-weight-medium);
    margin: 0 auto var(--space-6) auto;
    letter-spacing: -0.02em;
    max-width: 36ch;
}

.philosophy__content {
    max-width: 40rem;
    margin: 0 auto var(--space-16);
}

.philosophy__text {
    font-size: var(--text-md);
    color: var(--muted);
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-6);
}

.philosophy__text:last-child {
    margin-bottom: 0;
}

/* Capabilities */
.capabilities {
    max-width: var(--container-wide);
    margin: 0 auto;
    padding: 0;
}

.capabilities__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-4);
}

.capability {
    text-align: left;
}

.capability__title {
    font-size: var(--text-xl);
    font-weight: var(--font-weight-medium);
    margin-bottom: var(--space-2);
    letter-spacing: -0.01em;
}

.capability__description {
    font-size: var(--text-base);
    color: var(--muted);
    line-height: var(--leading-relaxed);
}

.capability__image {
    width: 100%;
    height: 14rem;
    overflow: hidden;
    border-radius: 0.75rem;
    margin-bottom: var(--space-8);
}

.capability__image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center center;
}

@media (max-width: 768px) {
    .capabilities__grid {
        grid-template-columns: 1fr;
        gap: var(--space-8);
    }
}

/* About section */
.about {
    padding: var(--space-32) 0;
    background-color: var(--surface);
}

.about__container {
    text-align: center;
    margin: 0 auto;
    max-width: 50rem;
    background: var(--surface);
    padding: var(--space-6);
    border-radius: 0.75rem;
}

.about__title {
    font-size: var(--text-4xl);
    font-weight: var(--font-weight-medium);
    margin: 0 auto var(--space-6) auto;
    text-align: center;
    letter-spacing: -0.02em;
}

.about__content {
    max-width: 48rem;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: var(--space-8);
    text-align: left;
}

.about__avatar {
    flex-shrink: 0;
    width: 4rem;
    height: 4rem;
    border-radius: 50%;
    background-color: var(--accent);
    display: flex;
    align-items: center;
    justify-content: center;
}

.about__avatar-text {
    color: var(--bg);
    font-weight: var(--font-weight-medium);
    font-size: var(--text-lg);
}

.about__text {
    font-size: var(--text-lg);
    color: var(--muted);
    line-height: var(--leading-relaxed);
}

@media (max-width: 768px) {
    .about__content {
        flex-direction: column;
        text-align: center;
        gap: var(--space-6);
    }
}

/* Footer */
.footer {
    padding: var(--space-20) 0 var(--space-8);
    text-align: center;
}

.footer__nav {
    margin-bottom: var(--space-8);
}

.footer__nav-list {
    display: flex;
    justify-content: center;
    gap: var(--space-8);
    list-style: none;
}

.footer__nav-link {
    font-size: var(--text-sm);
    color: var(--muted);
    font-weight: var(--font-weight-medium);
    transition: var(--transition-colors);
}

.footer__nav-link:hover {
    color: var(--text);
}

.footer__bottom {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--space-8);
    padding-top: var(--space-6);
}

.footer__copyright,
.footer__email {
    font-size: var(--text-sm);
    color: var(--muted);
}

.footer__email:hover {
    color: var(--text);
}

@media (max-width: 768px) {
    .footer__nav-list {
        gap: var(--space-6);
    }

    .footer__bottom {
        flex-direction: column;
        gap: var(--space-4);
    }
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(1rem);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    opacity: 0;
    animation: fadeInUp 0.6s ease forwards;
}

.fade-in-delay-1 {
    animation-delay: 0.1s;
}
.fade-in-delay-2 {
    animation-delay: 0.2s;
}
.fade-in-delay-3 {
    animation-delay: 0.3s;
}
.fade-in-delay-4 {
    animation-delay: 0.4s;
}

/* Utilities */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}