/* =============================
   CSS Variables (Light Theme)
   ============================= */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f5;
    --text-primary: #000000;
    --text-secondary: #707579;
    --border-color: #e0e0e0;
    --accent-color: #0088cc;
    --accent-hover: #0077b3;
    --shadow-light: rgba(0, 0, 0, 0.15);
    --shadow-medium: rgba(0, 0, 0, 0.2);
    --shadow-dark: rgba(0, 0, 0, 0.4);

    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.5;
    font-weight: 400;
    font-synthesis: none;
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* =============================
   Dark Theme
   ============================= */
.dark-theme {
    --bg-primary: #212121;
    --bg-secondary: #2c2c2c;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --border-color: #3a3a3a;
    --accent-color: #0088cc;
    --accent-hover: #0099dd;
    --shadow-light: rgba(0, 0, 0, 0.4);
    --shadow-medium: rgba(0, 0, 0, 0.5);
    --shadow-dark: rgba(0, 0, 0, 0.6);
}

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

html {
    height: 100%;
    scroll-behavior: smooth;
}

body {
    margin: 0;
    padding: 0;
    min-height: 100vh;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    transition: background-color 0.3s ease, color 0.3s ease;
    display: flex;
    flex-direction: column;
}

/* =============================
   Header
   ============================= */
.about-header {
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--header-bg, var(--bg-primary));
    border-bottom: 1px solid var(--border-color);
    z-index: 100;
    transition: background-color 0.3s ease, border-color 0.3s ease;
    box-shadow: 0 2px 4px var(--shadow-light);
}

.header-container {
    max-width: 960px;
    margin: 0 auto;
    padding: 12px 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.header-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: inherit;
    transition: opacity 0.2s ease;
}

.header-logo:hover {
    opacity: 0.8;
}

.logo-image {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
    flex-shrink: 0;
}

.logo-text {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.logo-title {
    margin: 0;
    font-size: 18px;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.2;
}

.logo-subtitle {
    margin: 0;
    font-size: 13px;
    color: var(--text-secondary);
    line-height: 1.2;
}

.header-nav {
    display: flex;
    align-items: center;
    gap: 16px;
}

.nav-link {
    padding: 8px 16px;
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
    border-radius: 8px;
    transition: color 0.2s ease, background-color 0.2s ease;
}

.nav-link:hover {
    color: var(--text-primary);
    background-color: var(--bg-secondary);
}

.nav-link.active {
    color: var(--accent-color);
    background-color: var(--bg-secondary);
}

.nav-link.lang-switch {
    padding: 6px 12px;
    font-size: 13px;
    border: 1px solid var(--border-color);
}

/* =============================
   Main Content
   ============================= */
.about-main {
    flex: 1;
    padding: 40px 16px;
}

.about-container {
    max-width: 960px;
    margin: 0 auto;
}

/* =============================
   Hero Section
   ============================= */
.about-hero {
    text-align: center;
    margin-bottom: 64px;
    padding: 32px 0;
}

.hero-title {
    font-size: 42px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 16px;
    line-height: 1.2;
}

.hero-description {
    font-size: 18px;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto 32px;
    line-height: 1.6;
}

.hero-description_link {
    color: var(--accent-color, #0088cc);
    text-decoration: underline;
    transition: color 0.2s ease;
    cursor: pointer;

    &:hover {
        color: var(--accent-hover, #0077b3);
    }

    &:active {
        color: #006699;
    }
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-top: 32px;
}

.hero-button {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    background-color: var(--accent-color);
    color: #ffffff;
    text-decoration: none;
    font-size: 16px;
    font-weight: 600;
    border-radius: 8px;
    transition: background-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: 0 2px 8px rgba(0, 136, 204, 0.3);
}

.hero-button:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 136, 204, 0.4);
}

.hero-button:active {
    transform: translateY(0);
}

.button-icon {
    font-size: 18px;
    transition: transform 0.2s ease;
}

.hero-button:hover .button-icon {
    transform: translateX(4px);
}

/* =============================
   Features Section
   ============================= */
.about-features {
    margin-bottom: 64px;
}

.section-title {
    font-size: 32px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 32px;
    text-align: center;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.feature-card {
    padding: 24px;
    background-color: var(--bg-secondary);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.feature-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow-medium);
}

.feature-icon {
    font-size: 40px;
    margin-bottom: 16px;
    line-height: 1;
}

.feature-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.feature-description {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin: 0;
}

/* =============================
   Mission Section
   ============================= */
.about-mission {
    margin-bottom: 64px;
    padding: 40px;
    background-color: var(--bg-secondary);
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.mission-text {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 16px;
}

.mission-text:last-child {
    margin-bottom: 0;
}

/* =============================
   Values Section
   ============================= */
.about-values {
    margin-bottom: 32px;
}

.values-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
}

.value-item {
    padding: 20px;
    background-color: var(--bg-secondary);
    border-radius: 8px;
    border-left: 3px solid var(--accent-color);
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.value-item strong {
    color: var(--text-primary);
    font-weight: 600;
    display: block;
    margin-bottom: 4px;
}

/* =============================
   Footer
   ============================= */
.about-footer {
    margin-top: auto;
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 40px 16px 24px;
}

.footer-container {
    max-width: 960px;
    margin: 0 auto;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 32px;
    margin-bottom: 32px;
}

.footer-section {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.footer-text {
    font-size: 14px;
    color: var(--text-secondary);
    margin: 0;
}

.footer-nav {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.footer-link {
    font-size: 14px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s ease;
}

.footer-link:hover {
    color: var(--accent-color);
}

.footer-bottom {
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.footer-copyright {
    font-size: 13px;
    color: var(--text-secondary);
    margin: 0;
}

/* =============================
   Responsive Design
   ============================= */
@media (max-width: 768px) {
    .header-container {
        flex-wrap: wrap;
    }

    .header-nav {
        width: 100%;
        justify-content: flex-end;
        margin-top: 8px;
    }

    .hero-title {
        font-size: 32px;
    }

    .hero-description {
        font-size: 16px;
    }

    .section-title {
        font-size: 28px;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .about-mission {
        padding: 24px;
    }

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

    .footer-content {
        grid-template-columns: 1fr;
        gap: 24px;
    }
}

@media (max-width: 480px) {
    .about-main {
        padding: 24px 12px;
    }

    .header-nav {
        gap: 10px;
    }

    .nav-link {
        padding: 8px 4px;
    }

    .about-hero {
        margin-bottom: 48px;
        padding: 24px 0;
    }

    .hero-title {
        font-size: 28px;
    }

    .about-features,
    .about-mission {
        margin-bottom: 48px;
    }

    .section-title {
        font-size: 24px;
        margin-bottom: 24px;
    }

    .feature-card {
        padding: 20px;
    }

    .about-mission {
        padding: 20px;
    }
}