/* ========================================
   Leaders&Readers - Modern Design System
   Version: 1.0
   ======================================== */

/* CSS Variables */
:root {
    /* Light Mode Colors */
    --primary-color: #0ea5e9;
    --primary-dark: #0284c7;
    --primary-light: #7dd3fc;
    --secondary-color: #14b8a6;
    --accent-color: #06b6d4;

    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;

    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-tertiary: #94a3b8;

    --border-color: #e2e8f0;
    --shadow-color: rgba(0, 0, 0, 0.1);

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 300ms ease;
    --transition-slow: 500ms ease;

    /* Container */
    --container-max: 1200px;
}

/* Dark Mode */
[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;

    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-tertiary: #64748b;

    --border-color: #334155;
    --shadow-color: rgba(0, 0, 0, 0.3);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition-base), color var(--transition-base);
}

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

ul {
    list-style: none;
}

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

button {
    cursor: pointer;
    border: none;
    background: none;
    font-family: inherit;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.3;
    color: var(--text-primary);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

@media (min-width: 768px) {
    h1 { font-size: 3.5rem; }
    h2 { font-size: 2.5rem; }
    h3 { font-size: 1.75rem; }
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.section-title h2 {
    margin-bottom: var(--spacing-md);
}

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

/* ========================================
   Header
   ======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    transition: background-color var(--transition-base), box-shadow var(--transition-base);
}

.header.scrolled {
    box-shadow: 0 4px 20px var(--shadow-color);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 800;
    font-size: 1.125rem;
}

.nav {
    display: none;
}

@media (min-width: 768px) {
    .nav {
        display: flex;
        align-items: center;
        gap: var(--spacing-xl);
    }
}

.nav-link {
    font-weight: 500;
    color: var(--text-secondary);
    position: relative;
    padding: var(--spacing-sm) 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width var(--transition-base);
}

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

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

/* Theme Toggle */
.theme-toggle {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-full);
    background-color: var(--bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color var(--transition-fast);
}

.theme-toggle:hover {
    background-color: var(--border-color);
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
    color: var(--text-secondary);
}

.theme-toggle .sun-icon {
    display: none;
}

[data-theme="dark"] .theme-toggle .moon-icon {
    display: none;
}

[data-theme="dark"] .theme-toggle .sun-icon {
    display: block;
}

/* Mobile Menu */
.mobile-menu-btn {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 10px;
}

.mobile-menu-btn span {
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: transform var(--transition-base);
}

@media (min-width: 768px) {
    .mobile-menu-btn {
        display: none;
    }
}

.mobile-nav {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-lg);
}

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

.mobile-nav a {
    display: block;
    padding: var(--spacing-md);
    color: var(--text-secondary);
    font-weight: 500;
    border-radius: var(--radius-md);
    transition: background-color var(--transition-fast);
}

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

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    box-shadow: 0 4px 15px rgba(14, 165, 233, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(14, 165, 233, 0.4);
}

.btn-secondary {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

.btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

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

.btn-lg {
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-size: 1.125rem;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    padding: 140px 0 80px;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 60%;
    height: 200%;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.05), rgba(20, 184, 166, 0.05));
    border-radius: 50%;
    transform: rotate(-15deg);
}

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

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

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    background-color: rgba(14, 165, 233, 0.1);
    color: var(--primary-color);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xl);
    animation: fadeInDown 0.6s ease;
}

.hero h1 {
    margin-bottom: var(--spacing-xl);
    animation: fadeInUp 0.6s ease 0.1s both;
}

.hero h1 span {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-2xl);
    animation: fadeInUp 0.6s ease 0.2s both;
}

.hero-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    justify-content: center;
    animation: fadeInUp 0.6s ease 0.3s both;
}

/* ========================================
   Cards
   ======================================== */
.card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    transition: all var(--transition-base);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px var(--shadow-color);
}

.card-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.1), rgba(20, 184, 166, 0.1));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
    font-size: 1.5rem;
}

.card h3 {
    margin-bottom: var(--spacing-md);
}

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

/* Service Cards */
.services-grid {
    display: grid;
    grid-template-columns: repeat(1, 1fr);
    gap: var(--spacing-xl);
}

@media (min-width: 640px) {
    .services-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .services-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.service-card {
    text-align: center;
}

.service-card .card-icon {
    margin: 0 auto var(--spacing-lg);
}

/* Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(1, 1fr);
    gap: var(--spacing-xl);
}

@media (min-width: 640px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .features-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.feature-card {
    text-align: center;
    padding: var(--spacing-2xl);
}

.feature-card .card-icon {
    margin: 0 auto var(--spacing-lg);
    width: 80px;
    height: 80px;
    font-size: 2rem;
}

/* ========================================
   Sections
   ======================================== */
section {
    padding: var(--spacing-3xl) 0;
}

@media (min-width: 768px) {
    section {
        padding: 80px 0;
    }
}

.section-alt {
    background-color: var(--bg-secondary);
}

/* CTA Section */
.cta-section {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    text-align: center;
    padding: 60px 0;
}

.cta-section h2 {
    color: white;
    margin-bottom: var(--spacing-md);
}

.cta-section p {
    opacity: 0.9;
    margin-bottom: var(--spacing-xl);
    font-size: 1.125rem;
}

.cta-section .btn-primary {
    background: white;
    color: var(--primary-color);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.cta-section .btn-primary:hover {
    transform: translateY(-2px);
}

/* ========================================
   About Page
   ======================================== */
.about-intro {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.about-intro p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

.company-info-table {
    max-width: 800px;
    margin: 0 auto;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.info-row {
    display: flex;
    border-bottom: 1px solid var(--border-color);
}

.info-row:last-child {
    border-bottom: none;
}

.info-label {
    flex: 0 0 150px;
    padding: var(--spacing-lg);
    background-color: var(--bg-secondary);
    font-weight: 600;
    color: var(--text-primary);
}

.info-value {
    flex: 1;
    padding: var(--spacing-lg);
    color: var(--text-secondary);
}

@media (max-width: 640px) {
    .info-row {
        flex-direction: column;
    }

    .info-label {
        flex: none;
        padding: var(--spacing-md) var(--spacing-lg);
    }

    .info-value {
        padding: var(--spacing-md) var(--spacing-lg);
    }
}

/* Values Grid */
.values-grid {
    display: grid;
    grid-template-columns: repeat(1, 1fr);
    gap: var(--spacing-xl);
}

@media (min-width: 768px) {
    .values-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.value-card {
    text-align: center;
    padding: var(--spacing-2xl);
}

.value-card .card-icon {
    margin: 0 auto var(--spacing-lg);
    width: 80px;
    height: 80px;
    font-size: 2rem;
}

/* ========================================
   Services Page
   ======================================== */
.service-detail-card {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.service-detail-card .card-icon {
    width: 70px;
    height: 70px;
    font-size: 1.75rem;
}

.service-detail-card ul {
    margin-top: var(--spacing-md);
}

.service-detail-card li {
    position: relative;
    padding-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

.service-detail-card li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.6em;
    width: 6px;
    height: 6px;
    background-color: var(--primary-color);
    border-radius: var(--radius-full);
}

/* Process Section */
.process-steps {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
    max-width: 800px;
    margin: 0 auto;
}

@media (min-width: 768px) {
    .process-steps {
        flex-direction: row;
        justify-content: space-between;
        align-items: flex-start;
    }
}

.process-step {
    flex: 1;
    text-align: center;
    position: relative;
}

@media (min-width: 768px) {
    .process-step:not(:last-child)::after {
        content: '';
        position: absolute;
        top: 35px;
        right: -50%;
        width: 100%;
        height: 2px;
        background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
        opacity: 0.3;
    }
}

.step-number {
    width: 70px;
    height: 70px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-lg);
    color: white;
    font-size: 1.5rem;
    font-weight: 700;
}

.process-step h4 {
    margin-bottom: var(--spacing-sm);
}

.process-step p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ========================================
   Contact Page
   ======================================== */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
}

@media (min-width: 1024px) {
    .contact-grid {
        grid-template-columns: 1fr 1fr;
    }
}

.contact-info-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.contact-item {
    display: flex;
    gap: var(--spacing-lg);
}

.contact-item-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, rgba(14, 165, 233, 0.1), rgba(20, 184, 166, 0.1));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.contact-item-content h4 {
    margin-bottom: var(--spacing-xs);
}

.contact-item-content p {
    color: var(--text-secondary);
}

/* Contact Form */
.contact-form-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-2xl);
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-md);
    font-size: 1rem;
    font-family: inherit;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.1);
}

.form-group textarea {
    min-height: 150px;
    resize: vertical;
}

/* Map Placeholder */
.map-placeholder {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-tertiary);
    margin-top: var(--spacing-2xl);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 60px 0 30px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
}

@media (min-width: 768px) {
    .footer-grid {
        grid-template-columns: 2fr 1fr 1fr 1fr;
    }
}

.footer-brand .logo {
    margin-bottom: var(--spacing-lg);
}

.footer-brand p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.footer-column h4 {
    margin-bottom: var(--spacing-lg);
    font-size: 1rem;
}

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

.footer-links a {
    color: var(--text-secondary);
    font-size: 0.875rem;
    transition: color var(--transition-fast);
}

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

.footer-bottom {
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    text-align: center;
}

@media (min-width: 768px) {
    .footer-bottom {
        flex-direction: row;
        justify-content: space-between;
        text-align: left;
    }
}

.footer-bottom p {
    color: var(--text-tertiary);
    font-size: 0.75rem;
}

.business-info {
    font-size: 0.75rem;
    color: var(--text-tertiary);
}

/* ========================================
   Animations
   ======================================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.animate-fade-in {
    animation: fadeIn 0.6s ease;
}

.animate-fade-in-up {
    animation: fadeInUp 0.6s ease;
}

/* Scroll Reveal */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* ========================================
   Utilities
   ======================================== */
.text-center { text-align: center; }
.text-primary { color: var(--primary-color); }
.mt-1 { margin-top: var(--spacing-md); }
.mt-2 { margin-top: var(--spacing-xl); }
.mt-3 { margin-top: var(--spacing-2xl); }
.mb-1 { margin-bottom: var(--spacing-md); }
.mb-2 { margin-bottom: var(--spacing-xl); }
.mb-3 { margin-bottom: var(--spacing-2xl); }

/* Page Header */
.page-header {
    padding: 140px 0 60px;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    text-align: center;
}

.page-header h1 {
    margin-bottom: var(--spacing-md);
}

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