/* ========================================
   CellBox Landing Page Styles
   - Light theme only (no dark mode)
   - Premium Minimal design
   ======================================== */

/* === Root Variables === */
:root {
    /* Primary Colors */
    --primary-blue: #2563eb;
    --primary-blue-hover: #1d4ed8;
    --primary-blue-light: #dbeafe;

    /* Neutral Colors */
    --text-primary: #1a202c;
    --text-secondary: #4a5568;
    --text-muted: #6b7280;
    --border-color: #e5e7eb;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-accent: #f0f9ff;

    /* Functional Colors */
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;

    /* Shadows */
    --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);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
                 "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* === Container === */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* === Notice Banner === */
.notice-banner {
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
    padding: 10px 16px;
    text-align: center;
    border-bottom: 1px solid #f59e0b;
}

.notice-content {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-size: 13px;
    color: #92400e;
    font-weight: 500;
}

.notice-content i {
    font-size: 14px;
}

/* === Header === */
.landing-header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: 16px 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.navbar-brand .logo {
    display: flex;
    align-items: center;
    text-decoration: none;
}

.logo-image {
    height: 32px;
    width: auto;
}

.navbar-menu {
    display: flex;
    align-items: center;
    gap: 24px;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
}

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

/* 모바일 네비게이션 아이콘 그룹 */
.mobile-nav-icons {
    display: none;
    align-items: center;
    gap: 8px;
}

.mobile-login-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 8px 16px;
    border-radius: 6px;
    background: var(--primary-blue);
    color: white;
    font-size: 14px;
    font-weight: 500;
    text-decoration: none;
    transition: background 0.2s;
    white-space: nowrap;
}

.mobile-login-btn:hover {
    background: var(--primary-blue-dark, #1a56db);
    color: white;
}

.mobile-menu-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--text-primary);
    cursor: pointer;
}

/* 모바일 메뉴 오버레이 (반투명 배경) */
.mobile-menu-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 998;
}

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

/* 메뉴 열림 시 스크롤 잠금 */
body.menu-open {
    overflow: hidden;
}

.mobile-menu {
    display: none;
    position: fixed;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: 24px;
    z-index: 1000;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

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

.mobile-nav-link {
    display: block;
    padding: 12px 0;
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
}

/* === Buttons === */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s ease;
    border: none;
    cursor: pointer;
    text-align: center;
}

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

.btn-primary:hover {
    background: var(--primary-blue-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.btn-outline {
    background: transparent;
    color: var(--primary-blue);
    border: 1px solid var(--primary-blue);
}

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

.btn-lg {
    padding: 16px 32px;
    font-size: 16px;
}

.btn-cta {
    background: #ffffff;
    color: var(--primary-blue);
    padding: 16px 40px;
    font-size: 18px;
}

.btn-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
}

.btn-block {
    width: 100%;
}

/* === Hero Section === */
.hero-section {
    padding: 80px 0;
    background: linear-gradient(135deg, #f0f9ff 0%, #ffffff 100%);
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-title {
    font-size: 48px;
    font-weight: 700;
    line-height: 1.2;
    color: var(--text-primary);
    margin-bottom: 16px;
}

.hero-subtitle {
    font-size: 20px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 32px;
}

.hero-cta {
    display: flex;
    gap: 16px;
    margin-bottom: 24px;
}

.hero-note {
    font-size: 14px;
    color: var(--text-muted);
}

.hero-note i {
    margin-right: 8px;
}

.hero-visual {
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-image {
    width: 100%;
    height: auto;
    max-width: 600px;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
}

.hero-image-placeholder {
    width: 100%;
    height: 400px;
    background: var(--bg-secondary);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* === Problem-Solution Section === */
.problem-solution-section {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.section-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
}

.section-title {
    font-size: 32px;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 32px;
}

.problem-list,
.solution-list {
    list-style: none;
}

.problem-item,
.solution-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 16px;
    font-size: 16px;
    line-height: 1.6;
}

.problem-item i {
    color: var(--danger-color);
    font-size: 20px;
    margin-top: 2px;
}

.solution-item i {
    color: var(--success-color);
    font-size: 20px;
    margin-top: 2px;
}

.solution-highlight {
    margin-top: 32px;
    padding: 16px;
    background: var(--primary-blue-light);
    border-left: 4px solid var(--primary-blue);
    font-weight: 600;
    color: var(--primary-blue);
}

/* === Features Section === */
.features-section {
    padding: 80px 0;
}

.section-heading {
    font-size: 36px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 48px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.feature-card {
    text-align: center;
    padding: 32px;
    background: var(--bg-primary);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

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

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 24px;
    background: var(--primary-blue-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.feature-icon i {
    font-size: 36px;
    color: var(--primary-blue);
}

.feature-title {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 16px;
}

.feature-description {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* === How it Works Section === */
.how-it-works-section {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.steps-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.step-item {
    position: relative;
}

.step-number {
    font-size: 48px;
    font-weight: 700;
    color: var(--primary-blue);
    opacity: 0.2;
    margin-bottom: 16px;
}

.step-title {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
}

.step-description {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 24px;
}

.step-visual {
    text-align: center;
    margin-top: 24px;
}

.step-icon {
    font-size: 60px;
    color: var(--primary-blue);
    opacity: 0.3;
}

/* === Trust Section === */
.trust-section {
    padding: 80px 0;
    background: var(--bg-accent);
}

.trust-description {
    text-align: center;
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 48px;
}

/* Company Logos */
.company-logos {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 40px;
    margin-bottom: 60px;
    padding: 40px 0;
}

.company-logo-item {
    flex: 0 1 180px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.company-logo-item img {
    max-width: 100%;
    height: auto;
    max-height: 60px;
    filter: grayscale(100%);
    opacity: 0.6;
    transition: all 0.3s ease;
}

.company-logo-item img:hover {
    filter: grayscale(0%);
    opacity: 1;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

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

.stat-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto 16px;
    background: var(--primary-blue-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.stat-icon i {
    font-size: 28px;
    color: var(--primary-blue);
}

.stat-number {
    font-size: 32px;
    font-weight: 700;
    color: var(--primary-blue);
    margin-bottom: 8px;
}

.stat-label {
    font-size: 14px;
    color: var(--text-muted);
}

/* === CTA Sections === */
.cta-section-middle {
    padding: 80px 0;
    background: var(--primary-blue);
    color: #ffffff;
    text-align: center;
}

.cta-title {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 16px;
    color: #ffffff;
}

.cta-description {
    font-size: 18px;
    margin-bottom: 32px;
    opacity: 0.9;
}

.cta-section-final {
    padding: 80px 0;
    text-align: center;
}

.cta-final-description {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 32px;
}

/* === Footer === */
.landing-footer {
    background: #1f2937;
    color: #9ca3af;
    padding: 48px 0 24px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-logo {
    height: 24px;
    width: auto;
    margin-bottom: 16px;
}

.footer-title {
    font-size: 20px;
    font-weight: 700;
    color: #ffffff;
    margin-bottom: 12px;
}

.footer-description {
    font-size: 14px;
    line-height: 1.6;
    margin-top: 12px;
}

.footer-heading {
    font-size: 16px;
    font-weight: 600;
    color: #ffffff;
    margin-bottom: 16px;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 8px;
}

.footer-links a {
    color: #9ca3af;
    text-decoration: none;
    font-size: 14px;
    transition: color 0.2s ease;
}

.footer-links a:hover {
    color: #ffffff;
}

.footer-bottom {
    padding-top: 24px;
    border-top: 1px solid #374151;
    text-align: center;
}

.copyright {
    font-size: 14px;
}

/* === Responsive Design === */

/* Tablet (768px ~ 1023px) */
@media (max-width: 1023px) {
    .hero-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .hero-title {
        font-size: 40px;
    }

    .hero-subtitle {
        font-size: 18px;
    }

    .section-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

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

    .steps-container {
        grid-template-columns: 1fr;
    }

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

    .company-logos {
        gap: 30px;
    }

    .company-logo-item {
        flex: 0 1 150px;
    }

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

/* Mobile (~ 767px) */
@media (max-width: 767px) {
    .container {
        padding: 0 16px;
    }

    .navbar-menu {
        display: none;
    }

    .mobile-nav-icons {
        display: flex;
    }

    .hero-section {
        padding: 48px 0;
    }

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

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

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

    .btn-lg {
        width: 100%;
    }

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

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

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

    .company-logos {
        gap: 20px;
        padding: 20px 0;
    }

    .company-logo-item {
        flex: 0 1 120px;
    }

    .company-logo-item img {
        max-height: 40px;
    }

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

    .problem-solution-section,
    .features-section,
    .how-it-works-section,
    .trust-section,
    .cta-section-middle,
    .cta-section-final {
        padding: 48px 0;
    }
}