/* ========================================
   AI4T Website - Main Stylesheet
   ======================================== */

/* ========== CSS Variables ========== */
:root {
    /* Colors */
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --primary-light: #3b82f6;
    --secondary-color: #10b981;
    --accent-color: #8b5cf6;

    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;

    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-dark: #111827;

    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans KR', sans-serif;
    --font-size-base: 16px;

    /* Spacing */
    --container-max-width: 1200px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;

    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 300ms ease-in-out;
}

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

html {
    font-size: var(--font-size-base);
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    color: var(--text-primary);
    background-color: var(--bg-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

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

ul {
    list-style: none;
}

/* ========== Container ========== */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ========== Navigation Bar ========== */
.navbar {
    background-color: var(--bg-primary);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
}

.nav-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
}

.logo {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-color);
    letter-spacing: -0.5px;
}

.logo-text {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-link {
    color: var(--text-primary);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 0.375rem;
    transition: all var(--transition-fast);
}

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

/* Dropdown */
.dropdown {
    position: relative;
}

.dropdown-toggle::after {
    content: ' ▾';
    font-size: 0.875rem;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background-color: var(--bg-primary);
    box-shadow: var(--shadow-lg);
    border-radius: 0.5rem;
    padding: var(--spacing-xs);
    min-width: 200px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-base);
    margin-top: var(--spacing-xs);
}

.dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-item {
    display: block;
    padding: var(--spacing-xs) var(--spacing-sm);
    color: var(--text-primary);
    border-radius: 0.375rem;
    transition: all var(--transition-fast);
}

.dropdown-item:hover {
    background-color: var(--bg-secondary);
    color: var(--primary-color);
}

/* Mobile Menu */
.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.hamburger {
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: all var(--transition-base);
}

.mobile-menu {
    display: none;
    position: fixed;
    top: 65px;
    left: 0;
    right: 0;
    background-color: var(--bg-primary);
    box-shadow: var(--shadow-lg);
    padding: var(--spacing-md);
    transform: translateY(-100%);
    transition: transform var(--transition-base);
    z-index: 999;
}

.mobile-menu.active {
    transform: translateY(0);
}

.mobile-nav-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.mobile-nav-link {
    display: block;
    padding: var(--spacing-sm);
    color: var(--text-primary);
    font-weight: 500;
    border-radius: 0.375rem;
    transition: all var(--transition-fast);
}

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

.mobile-dropdown-menu {
    padding-left: var(--spacing-md);
    margin-top: var(--spacing-xs);
    display: none;
}

.mobile-dropdown.active .mobile-dropdown-menu {
    display: block;
}

.mobile-dropdown-item {
    display: block;
    padding: var(--spacing-xs) var(--spacing-sm);
    color: var(--text-secondary);
}

/* Language Toggle */
.language-toggle {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.lang-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.875rem;
    cursor: pointer;
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    transition: all var(--transition-fast);
}

.lang-btn:hover {
    color: var(--primary-color);
    background-color: var(--bg-secondary);
}

.lang-btn.active {
    color: var(--primary-color);
    font-weight: 700;
}

.lang-separator {
    color: var(--text-light);
    font-size: 0.875rem;
}

.mobile-language-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: var(--spacing-sm);
    margin-top: var(--spacing-sm);
    border-top: 1px solid var(--border-color);
}

/* ========== Messages ========== */
.messages-container {
    position: fixed;
    top: 80px;
    right: var(--spacing-md);
    z-index: 1001;
    max-width: 400px;
}

.alert {
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 0.5rem;
    margin-bottom: var(--spacing-sm);
    box-shadow: var(--shadow-md);
    animation: slideIn 0.3s ease-out;
}

.alert-success {
    background-color: #d1fae5;
    color: #065f46;
    border-left: 4px solid var(--secondary-color);
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }

    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* ========== Hero Section ========== */
.hero {
    position: relative;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: var(--spacing-2xl) 0;
    min-height: 500px;
    display: flex;
    align-items: center;
    overflow: hidden;
}

.hero-overlay {
    position: absolute;
    inset: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="40" height="40" patternUnits="userSpaceOnUse"><path d="M 40 0 L 0 0 0 40" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.5;
}

.hero-container {
    position: relative;
    z-index: 1;
}

.hero-content {
    max-width: 700px;
    text-align: center;
    margin: 0 auto;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xl);
    opacity: 0.95;
    line-height: 1.6;
}

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

/* ========== Buttons ========== */
.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    border-radius: 0.5rem;
    font-weight: 600;
    font-size: 1rem;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-base);
    border: none;
    box-shadow: var(--shadow-md);
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background-color: transparent;
    color: white;
    border: 2px solid white;
}

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

.btn-cta {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: white;
}

.btn-cta:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.btn-submit {
    width: 100%;
}

/* ========== Sections ========== */
section {
    padding: var(--spacing-2xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ========== Services Section ========== */
.services-section {
    background-color: var(--bg-secondary);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.service-card {
    background-color: var(--bg-primary);
    padding: var(--spacing-xl);
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.service-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.service-card-placeholder {
    opacity: 0.7;
    border: 2px dashed var(--border-color);
    box-shadow: none;
}

.service-icon {
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
    color: white;
}

.service-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.service-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.7;
}

.service-link {
    color: var(--primary-color);
    font-weight: 600;
    transition: all var(--transition-fast);
}

.service-link:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

/* ========== Highlights Section ========== */
.highlights-section {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: white;
}

.highlights-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    text-align: center;
}

.highlight-item {
    padding: var(--spacing-lg);
}

.highlight-number {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: var(--spacing-xs);
}

.highlight-label {
    font-size: 1.125rem;
    opacity: 0.9;
}

/* ========== CTA Section ========== */
.cta-section {
    background-color: var(--bg-secondary);
    text-align: center;
}

.cta-content {
    max-width: 700px;
    margin: 0 auto;
}

.cta-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.cta-text {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xl);
}

/* CTA text color is defined in specific contexts (e.g., .service-cta .cta-text) */

/* ========== Page Header ========== */
.page-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: var(--spacing-2xl) 0;
    text-align: center;
}

.page-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.page-subtitle {
    font-size: 1.125rem;
    opacity: 0.9;
}

/* ========== About Page ========== */
.about-section {
    background-color: var(--bg-primary);
}

.about-content {
    display: grid;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-2xl);
}

.content-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.content-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.values-section {
    margin-bottom: var(--spacing-2xl);
}

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

.value-card {
    padding: var(--spacing-lg);
    background-color: var(--bg-secondary);
    border-radius: 1rem;
    text-align: center;
    transition: all var(--transition-base);
}

.value-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.value-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--spacing-md);
    color: var(--primary-color);
}

.value-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.value-description {
    color: var(--text-secondary);
    line-height: 1.6;
}

.company-info {
    background-color: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: 1rem;
}

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

.info-item {
    text-align: center;
}

.info-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.info-value {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* ========== Service Detail Page ========== */
.service-detail-section {
    background-color: var(--bg-primary);
}

.service-intro {
    max-width: 800px;
    margin: 0 auto var(--spacing-2xl);
    text-align: center;
}

.features-section {
    margin-bottom: var(--spacing-2xl);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.feature-card {
    padding: var(--spacing-lg);
    background-color: var(--bg-secondary);
    border-radius: 1rem;
    transition: all var(--transition-base);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    width: 56px;
    height: 56px;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.feature-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.feature-description {
    color: var(--text-secondary);
    line-height: 1.6;
}

.benefits-section {
    margin-bottom: var(--spacing-2xl);
}

.benefits-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.benefit-item {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    background-color: var(--bg-secondary);
    border-radius: 1rem;
}

.benefit-number {
    font-size: 2rem;
    font-weight: 800;
    color: var(--primary-color);
    flex-shrink: 0;
}

.benefit-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.benefit-description {
    color: var(--text-secondary);
    line-height: 1.6;
}

.service-cta {
    text-align: center;
    padding: var(--spacing-xl);
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: 1rem;
    color: white;
}

.service-cta .cta-title,
.service-cta .cta-text {
    color: white !important;
}

/* ========== Contact Page ========== */
.contact-section {
    background-color: var(--bg-primary);
}

.contact-info-centered {
    max-width: 800px;
    margin: 0 auto;
    background-color: var(--bg-secondary);
    padding: var(--spacing-2xl);
    border-radius: 1rem;
}

.contact-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    max-width: 1000px;
    margin: 0 auto;
}

.contact-form-container,
.contact-info-container {
    background-color: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: 1rem;
}

.form-heading,
.info-heading {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.form-label {
    font-weight: 600;
    color: var(--text-primary);
}

.form-input,
.form-textarea {
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    font-size: 1rem;
    font-family: inherit;
    transition: all var(--transition-fast);
    background-color: var(--bg-primary);
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-error {
    color: #dc2626;
    font-size: 0.875rem;
}

.contact-info-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.contact-info-item {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background-color: var(--bg-primary);
    border-radius: 0.5rem;
}

.info-icon {
    width: 48px;
    height: 48px;
    background-color: var(--bg-secondary);
    border-radius: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    flex-shrink: 0;
}

.info-details {
    flex: 1;
}

.info-title {
    font-weight: 600;
    margin-bottom: 0.25rem;
    color: var(--text-primary);
}

.info-text {
    color: var(--text-secondary);
}

.info-subtext {
    color: var(--text-light);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.contact-info-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

.contact-note {
    padding: var(--spacing-md);
    background-color: #dbeafe;
    border-left: 4px solid var(--primary-color);
    border-radius: 0.5rem;
    color: var(--text-primary);
}

/* ========== Footer ========== */
.footer {
    background-color: var(--bg-dark);
    color: white;
    padding: var(--spacing-2xl) 0 var(--spacing-md);
}

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

.footer-section {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.footer-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
}

.footer-description {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.6;
}

.footer-heading {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.footer-links,
.footer-contact {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    transition: color var(--transition-fast);
}

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

.footer-contact li {
    color: rgba(255, 255, 255, 0.8);
}

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

/* ========== Privacy Policy Page ========== */
.privacy-section {
    background-color: var(--bg-primary);
}

.privacy-content {
    max-width: 800px;
    margin: 0 auto;
    background-color: var(--bg-secondary);
    padding: var(--spacing-2xl);
    border-radius: 1rem;
}

.privacy-updated {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
}

.privacy-block {
    margin-bottom: var(--spacing-xl);
}

.privacy-heading {
    font-size: 1.375rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.privacy-block p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-sm);
}

.privacy-list {
    list-style: disc;
    padding-left: var(--spacing-md);
    color: var(--text-secondary);
    line-height: 1.8;
}

.privacy-list li {
    margin-bottom: var(--spacing-xs);
}

.privacy-list-none {
    list-style: none;
    padding-left: 0;
}

.privacy-footer-info {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-secondary);
}

.privacy-footer-info p {
    margin-bottom: var(--spacing-xs);
}

/* Footer Bottom Link */
.footer-bottom-link {
    color: rgba(255, 255, 255, 0.6);
    transition: color var(--transition-fast);
}

.footer-bottom-link:hover {
    color: var(--primary-light);
}

/* ========== Responsive Design ========== */
@media (max-width: 768px) {

    /* Navigation */
    .nav-menu {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .mobile-menu {
        display: block;
    }

    /* Hero */
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-buttons {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    /* Sections */
    .section-title {
        font-size: 2rem;
    }

    .page-title {
        font-size: 2rem;
    }

    /* Services */
    .services-grid {
        grid-template-columns: 1fr;
    }

    /* Contact */
    .contact-wrapper {
        grid-template-columns: 1fr;
    }

    /* Footer */
    .footer-content {
        grid-template-columns: 1fr;
    }

    /* Messages */
    .messages-container {
        left: var(--spacing-md);
        right: var(--spacing-md);
        max-width: none;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-xl: 2rem;
        --spacing-2xl: 3rem;
    }

    .hero {
        min-height: 400px;
    }

    .hero-title {
        font-size: 1.75rem;
    }

    .section-title {
        font-size: 1.75rem;
    }

    .highlight-number {
        font-size: 2rem;
    }
}