/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Snowflake Color Palette */
    --primary-blue: #29B5E8;
    --dark-blue: #043464;
    --navy: #0E1C3D;
    --light-blue: #56C4EF;
    --ice-blue: #E8F7FC;
    --white: #FFFFFF;
    --light-gray: #F5F7FA;
    --gray: #6B7280;
    --dark-gray: #374151;
    --text-dark: #111827;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--white);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Navigation */
.navbar {
    background-color: var(--white);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: var(--spacing-md) 0;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    display: flex;
    align-items: center;
}

.logo-image {
    height: 70px;
    width: auto;
    max-width: 450px;
    transition: transform 0.3s ease;
}

.logo-image:hover {
    transform: scale(1.05);
}

.logo-text {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-blue);
    letter-spacing: -0.02em;
}

.logo-subtitle {
    font-size: 0.75rem;
    color: var(--gray);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
}

.nav-links a {
    color: var(--dark-gray);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    padding: 0.5rem 0;
}

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

/* Mobile Menu Toggle Button */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 28px;
    height: 20px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 1001;
}

.hamburger-line {
    display: block;
    width: 100%;
    height: 3px;
    background-color: var(--dark-blue);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.mobile-menu-toggle.active .hamburger-line:nth-child(1) {
    transform: translateY(8.5px) rotate(45deg);
}

.mobile-menu-toggle.active .hamburger-line:nth-child(2) {
    opacity: 0;
}

.mobile-menu-toggle.active .hamburger-line:nth-child(3) {
    transform: translateY(-8.5px) rotate(-45deg);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--dark-blue) 0%, var(--navy) 100%);
    color: var(--white);
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.hero-content {
    max-width: 900px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-lg);
    opacity: 0.95;
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background-color: var(--primary-blue);
    color: var(--white);
}

.btn-primary:hover {
    background-color: var(--light-blue);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(41, 181, 232, 0.3);
}

.btn-secondary {
    background-color: transparent;
    color: var(--white);
    border-color: var(--white);
}

.btn-secondary:hover {
    background-color: var(--white);
    color: var(--dark-blue);
}

.btn-outline {
    background-color: transparent;
    color: var(--primary-blue);
    border-color: var(--primary-blue);
}

.btn-outline:hover {
    background-color: var(--primary-blue);
    color: var(--white);
}

.btn svg {
    vertical-align: middle;
    margin-right: 0.5rem;
}

/* Sections */
section {
    padding: var(--spacing-xl) 0;
}

section h2 {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--dark-blue);
}

section h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--dark-blue);
}

/* About Section */
.about {
    background-color: var(--white);
}

.about-content {
    max-width: 800px;
    margin: 0 auto var(--spacing-lg) auto;
    text-align: center;
}

.about-content p {
    font-size: 1.125rem;
    color: var(--dark-gray);
    margin-bottom: var(--spacing-sm);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.feature-card {
    background-color: var(--light-gray);
    padding: var(--spacing-md);
    border-radius: 12px;
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.feature-card h3 {
    color: var(--dark-blue);
    margin-bottom: var(--spacing-xs);
}

.feature-card p {
    color: var(--dark-gray);
    font-size: 0.95rem;
}

/* Why OSI Section */
.why-osi {
    background-color: var(--ice-blue);
}

.why-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(400px, 100%), 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-md);
}

.why-text {
    background-color: var(--white);
    padding: var(--spacing-md);
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.why-text ul {
    margin-top: var(--spacing-sm);
    padding-left: var(--spacing-md);
}

.why-text li {
    margin-bottom: var(--spacing-xs);
    color: var(--dark-gray);
}

/* Members Section */
.members {
    background-color: var(--white);
}

.members-intro {
    text-align: center;
    font-size: 1.125rem;
    color: var(--gray);
    margin-bottom: var(--spacing-lg);
}

.members-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.member-card {
    background-color: var(--white);
    padding: var(--spacing-md);
    border-radius: 8px;
    text-align: center;
    font-weight: 600;
    color: var(--dark-blue);
    border: 2px solid var(--light-gray);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    min-height: 120px;
}

.member-card img {
    max-width: 120px;
    max-height: 60px;
    width: auto;
    height: auto;
    object-fit: contain;
    filter: grayscale(0%);
    transition: all 0.3s ease;
}

.member-card:hover {
    border-color: var(--primary-blue);
    background-color: var(--ice-blue);
    transform: translateY(-4px);
    box-shadow: 0 8px 20px rgba(41, 181, 232, 0.15);
}

.member-card:hover img {
    transform: scale(1.1);
}

.member-card .company-name {
    font-size: 0.875rem;
    color: var(--dark-gray);
    font-weight: 500;
    margin-top: var(--spacing-xs);
}

/* Specification Section */
.specification {
    background-color: var(--light-gray);
}

.spec-intro {
    text-align: center;
    max-width: 800px;
    margin: 0 auto var(--spacing-lg) auto;
}

.spec-intro p {
    font-size: 1.125rem;
    color: var(--dark-gray);
}

.spec-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(300px, 100%), 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.spec-card {
    background-color: var(--white);
    padding: var(--spacing-md);
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
}

.spec-card ul {
    list-style: none;
    padding: 0;
}

.spec-card li {
    padding: var(--spacing-xs) 0;
    color: var(--dark-gray);
    border-bottom: 1px solid var(--light-gray);
}

.spec-card li:last-child {
    border-bottom: none;
}

.spec-links {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    flex-wrap: wrap;
    margin-top: var(--spacing-lg);
}

/* OSI Updates Section */
.updates {
    background-color: var(--white);
}

.updates-intro {
    text-align: center;
    font-size: 1.125rem;
    color: var(--gray);
    margin-bottom: var(--spacing-lg);
}

.updates-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(350px, 100%), 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.update-card {
    background-color: var(--light-gray);
    padding: var(--spacing-md);
    border-radius: 12px;
    border-left: 4px solid var(--primary-blue);
    transition: all 0.3s ease;
}

.update-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    border-left-color: var(--light-blue);
}

.update-date {
    font-size: 0.875rem;
    color: var(--primary-blue);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-xs);
}

.update-card h3 {
    color: var(--dark-blue);
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
    line-height: 1.4;
}

.update-card p {
    color: var(--dark-gray);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.update-link {
    color: var(--primary-blue);
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    display: inline-block;
}

.update-link:hover {
    color: var(--light-blue);
    transform: translateX(4px);
}

/* Get Involved Section */
.get-involved {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--light-blue) 100%);
    color: var(--white);
}

.get-involved h2 {
    color: var(--white);
}

.involvement-intro, .involvement-join {
    text-align: center;
    font-size: 1.125rem;
    color: var(--white);
    margin-bottom: var(--spacing-lg);
}

.involvement-join a {
    color: var(--white);
    text-decoration: underline;
    font-weight: 600;
}

.involvement-join a:hover {
    color: var(--navy);
}

.involvement-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.involvement-card {
    background-color: rgba(255, 255, 255, 0.95);
    padding: var(--spacing-md);
    border-radius: 12px;
    text-align: center;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.involvement-card h3 {
    color: var(--dark-blue);
    margin-bottom: var(--spacing-sm);
}

.involvement-card p {
    color: var(--dark-gray);
    margin-bottom: var(--spacing-md);
    flex-grow: 1;
}

/* Footer */
.footer {
    background-color: var(--navy);
    color: var(--white);
    padding: var(--spacing-lg) 0 var(--spacing-md) 0;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.footer-section h4 {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-sm);
    font-size: 1.125rem;
}

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: var(--spacing-xs);
}

.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-md);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
}

.footer-bottom p {
    margin: var(--spacing-xs) 0;
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 1200px) {
    .involvement-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.125rem;
    }

    /* Mobile Navigation */
    .mobile-menu-toggle {
        display: flex;
    }

    .navbar .container {
        flex-wrap: wrap;
    }

    .nav-links {
        display: none;
        flex-direction: column;
        width: 100%;
        gap: 0;
        padding-top: var(--spacing-md);
        border-top: 1px solid var(--light-gray);
        margin-top: var(--spacing-md);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links a {
        padding: var(--spacing-sm) 0;
        border-bottom: 1px solid var(--light-gray);
        font-size: 1rem;
    }

    .nav-links a:last-child {
        border-bottom: none;
    }

    .why-content {
        grid-template-columns: 1fr;
    }

    section h2 {
        font-size: 2rem;
    }

    .features-grid,
    .spec-grid,
    .involvement-grid,
    .updates-grid {
        grid-template-columns: 1fr;
    }

    .logo-image {
        height: 50px;
        max-width: 300px;
    }
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Animation */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

section > .container > * {
    animation: fadeIn 0.6s ease-out;
}