/* HUFS Portfolio - Design System */
:root {
    --hufs-blue: #003366;
    --hufs-gold: #C5A059;
    --hufs-white: #FFFFFF;
    --hufs-bg: #F8F9FA;
    --hufs-text: #333333;
    --hufs-gray: #777777;
    --hufs-shadow: 0 4px 20px rgba(0, 51, 102, 0.1);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, 'Helvetica Neue', 'Segoe UI', 'Apple SD Gothic Neo', 'Noto Sans KR', 'Malgun Gothic', 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol', sans-serif;
}

html {
    scroll-behavior: smooth;
}

body {
    background-color: var(--hufs-white);
    color: var(--hufs-text);
    line-height: 1.6;
}

li {
    list-style: none;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 100px 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: var(--hufs-blue);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--hufs-gold);
    margin: 15px auto 0;
}

.bg-light {
    background-color: var(--hufs-bg);
}

/* Header & Nav */
header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    height: 80px;
    display: flex;
    align-items: center;
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.logo {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--hufs-blue);
}

.logo span {
    color: var(--hufs-gold);
}

nav ul {
    display: flex;
    gap: 30px;
}

nav ul li a {
    font-weight: 500;
    color: var(--hufs-blue);
}

nav ul li a:hover {
    color: var(--hufs-gold);
}

/* Hero Section */
.hero {
    height: 100vh;
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    color: var(--hufs-white);
    padding-top: 80px;
}

.hero-content h1 {
    font-size: 4rem;
    margin-bottom: 20px;
    animation: fadeInUp 1s ease;
}

.hero-content h1 span {
    color: var(--hufs-gold);
}

.hero-content .subtitle {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: 2px;
    margin-bottom: 30px;
    opacity: 0.9;
    animation: fadeInUp 1s ease 0.2s backwards;
}

.hero-content .intro {
    font-size: 1.2rem;
    max-width: 800px;
    margin-bottom: 40px;
    opacity: 0.8;
    animation: fadeInUp 1s ease 0.4s backwards;
}

.btn {
    display: inline-block;
    padding: 15px 40px;
    background: var(--hufs-gold);
    color: var(--hufs-white);
    font-weight: 600;
    border-radius: 50px;
    box-shadow: 0 4px 15px rgba(197, 160, 89, 0.3);
    animation: fadeInUp 1s ease 0.6s backwards;
}

.btn:hover {
    background: var(--hufs-blue);
    transform: translateY(-3px);
}

/* About Section */
.about-flex {
    display: flex;
    align-items: center;
    gap: 60px;
}

.about-img {
    flex: 1;
    text-align: center;
}

.about-img img {
    width: 300px;
    height: 300px;
    border-radius: 50%;
    object-fit: cover;
    border: 8px solid var(--hufs-bg);
    box-shadow: var(--hufs-shadow);
}

.about-text {
    flex: 2;
}

.about-text p {
    font-size: 1.1rem;
    margin-bottom: 20px;
    color: var(--hufs-gray);
}

.keywords {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 30px;
}

.keywords span {
    padding: 8px 15px;
    background: var(--hufs-bg);
    color: var(--hufs-blue);
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    border: 1px solid rgba(0, 51, 102, 0.1);
}

/* Experience Section (Timeline) */
.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::after {
    content: '';
    position: absolute;
    width: 2px;
    background: var(--hufs-gold);
    top: 0;
    bottom: 0;
    left: 20px;
}

.timeline-item {
    padding: 20px 40px;
    position: relative;
    background: transparent;
    width: 100%;
}

.timeline-dot {
    position: absolute;
    width: 16px;
    height: 16px;
    background: var(--hufs-white);
    border: 3px solid var(--hufs-gold);
    border-radius: 50%;
    left: 13px;
    top: 35px;
    z-index: 10;
}

.timeline-date {
    font-weight: 700;
    color: var(--hufs-gold);
    margin-bottom: 10px;
    font-size: 1.1rem;
}

.timeline-content {
    background: var(--hufs-white);
    padding: 25px;
    border-radius: 12px;
    box-shadow: var(--hufs-shadow);
}

.timeline-content h3 {
    color: var(--hufs-blue);
    margin-bottom: 10px;
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 30px;
}

.skill-card {
    background: var(--hufs-white);
    padding: 40px 30px;
    border-radius: 15px;
    text-align: center;
    box-shadow: var(--hufs-shadow);
    transition: var(--transition);
}

.skill-card:hover {
    transform: translateY(-10px);
    border-bottom: 4px solid var(--hufs-gold);
}

.skill-card i {
    font-size: 3rem;
    color: var(--hufs-gold);
    margin-bottom: 20px;
}

.skill-card h3 {
    color: var(--hufs-blue);
    margin-bottom: 15px;
}

/* Global Perspective Section */
.global-perspective {
    height: 300px;
    background: linear-gradient(rgba(0, 51, 102, 0.8), rgba(0, 51, 102, 0.8)), url('https://images.unsplash.com/photo-1521295121783-8a321d551ad2?ixlib=rb-1.2.1&auto=format&fit=crop&w=1350&q=80');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--hufs-white);
}

.world-icon {
    font-size: 4rem;
    color: var(--hufs-gold);
    margin-bottom: 20px;
}

.global-perspective h2 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

/* Projects Section */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 40px;
}

.project-card {
    background: var(--hufs-white);
    border-radius: 15px;
    overflow: hidden;
    position: relative;
    box-shadow: var(--hufs-shadow);
    height: 250px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 30px;
    border: 1px solid rgba(0, 51, 102, 0.05);
}

.project-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: var(--hufs-gold);
}

.project-info h3 {
    color: var(--hufs-blue);
    font-size: 1.5rem;
    margin-bottom: 15px;
}

.project-info p {
    color: var(--hufs-gray);
    margin-bottom: 20px;
}

.project-link {
    font-weight: 600;
    color: var(--hufs-gold);
    display: flex;
    align-items: center;
    gap: 8px;
}

.project-link:hover {
    color: var(--hufs-blue);
}

/* Contact Section */
.contact-content {
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.contact-content p {
    font-size: 1.2rem;
    margin-bottom: 40px;
}

.contact-links {
    display: flex;
    justify-content: center;
    gap: 40px;
}

.contact-links a {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--hufs-blue);
}

.contact-links a:hover {
    color: var(--hufs-gold);
}

/* Footer */
footer {
    background: var(--hufs-blue);
    color: var(--hufs-white);
    text-align: center;
    padding: 30px 0;
}

footer p {
    opacity: 0.8;
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .hero-content h1 {
        font-size: 2.5rem;
    }
    
    .about-flex {
        flex-direction: column;
        gap: 40px;
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    nav ul {
        display: none; /* simple fix for mobile nav */
    }
    
    .contact-links {
        flex-direction: column;
        gap: 20px;
    }
}