/* ===== CSS RESET & BASE ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    line-height: 1.6;
    color: #1d1d1f;
    background-color: #fafafa;
    font-weight: 400;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===== TYPOGRAPHY SYSTEM ===== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    color: #1d1d1f;
}

h1 { font-size: 3.5rem; font-weight: 700; }
h2 { font-size: 2.5rem; font-weight: 600; }
h3 { font-size: 1.5rem; font-weight: 600; }
h4 { font-size: 1.25rem; font-weight: 500; }

p {
    color: #515154;
    line-height: 1.7;
}

a {
    color: #007aff;
    text-decoration: none;
    transition: all 0.2s ease;
}

a:hover {
    color: #0051d5;
}

/* ===== LAYOUT CONTAINERS ===== */
.main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* ===== HEADER & NAVIGATION ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(250, 250, 250, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    z-index: 1000;
    padding: 0 2rem;
}

.nav {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-brand .brand-link {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1d1d1f;
    text-decoration: none;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    font-size: 0.95rem;
    font-weight: 400;
    color: #515154;
    transition: color 0.2s ease;
    padding: 0.5rem 0;
}

.nav-link:hover {
    color: #007aff;
}

/* ===== HERO SECTION ===== */
.hero {
    padding: 100px 0 0px;
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.hero-title-section {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.hero-title-group {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
}

.profile-image {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.25);
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 600;
    margin: 0;
    color: #1d1d1f;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 500;
    color: #007aff;
    margin: 0;
}

.hero-description {
    font-size: 1.125rem;
    color: #515154;
    line-height: 1.4;
    margin: 0 auto;
}

/* ===== RESUME SECTION ===== */
.resume-content {
    padding: 100px 0;
}

.resume-layout {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 3rem;
    max-width: 1200px;
    margin: 0 auto;
}

.resume-sidebar {
    background: #ffffff;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    border: 1px solid rgba(0, 0, 0, 0.05);
    height: fit-content;
    position: sticky;
    top: 100px;
}

.sidebar-section {
    margin-bottom: 2.5rem;
}

.sidebar-section:last-child {
    margin-bottom: 0;
}

.download-section {
    text-align: center;
    margin-bottom: 2rem;
}

.download-section .download-btn {
    width: 100%;
    justify-content: center;
}

.sidebar-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1d1d1f;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #007aff;
}

.skill-group,
.award-group {
    margin-bottom: 1.5rem;
}

.skill-group:last-child,
.award-group:last-child {
    margin-bottom: 0;
}

.skill-group h4,
.award-group h4 {
    font-size: 1rem;
    font-weight: 600;
    color: #515154;
    margin-bottom: 0.75rem;
}

.skill-list,
.award-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.skill-list li,
.award-list li {
    font-size: 0.9rem;
    line-height: 1.5;
    color: #515154;
    margin-bottom: 0.5rem;
    padding-left: 1rem;
    position: relative;
}

.skill-list li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: #007aff;
    font-weight: 600;
}

.award-list li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: #007aff;
    font-weight: 600;
}

.resume-main {
    min-width: 0;
}

/* ===== TIMELINE SECTION ===== */
.timeline {
    padding: 100px 0;
}

.timeline-header {
    text-align: center;
    margin-bottom: 80px;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #1d1d1f;
}

.section-subtitle {
    font-size: 1.125rem;
    color: #515154;
    max-width: 600px;
    margin: 0 auto;
}

.timeline-content {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
}

/* Timeline Line */
.timeline-content::before {
    content: '';
    position: absolute;
    left: 30px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, #007aff, #5ac8fa);
    border-radius: 1px;
}

/* ===== TIMELINE ITEMS ===== */
.timeline-item {
    position: relative;
    margin-bottom: 3rem;
    padding-left: 80px;
}

.timeline-marker {
    position: absolute;
    left: 22px;
    top: 30px;
    width: 18px;
    height: 18px;
    background: #007aff;
    border: 3px solid #fafafa;
    border-radius: 50%;
    box-shadow: 0 2px 8px rgba(0, 122, 255, 0.3);
    z-index: 2;
}

.timeline-item.current .timeline-marker {
    background: #34c759;
    box-shadow: 0 2px 8px rgba(52, 199, 89, 0.4);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { box-shadow: 0 2px 8px rgba(52, 199, 89, 0.4); }
    50% { box-shadow: 0 2px 16px rgba(52, 199, 89, 0.6); }
    100% { box-shadow: 0 2px 8px rgba(52, 199, 89, 0.4); }
}

/* ===== TIMELINE CARDS ===== */
.timeline-card {
    background: #ffffff;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    border: 1px solid rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.timeline-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #007aff, #5ac8fa);
    border-radius: 16px 16px 0 0;
}

.timeline-item.current .timeline-card::before {
    background: linear-gradient(90deg, #34c759, #30d158);
}

.timeline-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1);
}

.card-header {
    margin-bottom: 1.5rem;
}

.card-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: #1d1d1f;
    margin-bottom: 0.5rem;
}

.card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.company {
    font-size: 1rem;
    font-weight: 500;
    color: #007aff;
}

.period {
    font-size: 0.9rem;
    font-weight: 500;
    color: #8e8e93;
    background: #f2f2f7;
    padding: 0.25rem 0.75rem;
    border-radius: 8px;
}

.card-content {
    color: #515154;
}

.card-description {
    font-size: 1rem;
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.card-highlights {
    list-style: none;
    padding: 0;
}

.card-highlights li {
    position: relative;
    padding-left: 1.5rem;
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
    line-height: 1.5;
}

.card-highlights li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: #007aff;
    font-weight: 600;
}

/* ===== SKILLS & ACHIEVEMENTS SECTION ===== */
.skills-achievements {
    padding: 100px 0;
    background: #f8f9fa;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    background: #007aff;
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: all 0.2s ease;
    box-shadow: 0 2px 8px rgba(0, 122, 255, 0.3);
}

.download-btn:hover {
    background: #0051d5;
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(0, 122, 255, 0.4);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.skill-category {
    background: #ffffff;
    padding: 2rem;
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    border: 1px solid rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.skill-category:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1);
}

.skill-category h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: #1d1d1f;
    margin-bottom: 1.5rem;
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.skill-tag {
    background: #f2f2f7;
    color: #515154;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.2s ease;
}

.skill-tag:hover {
    background: #e3f2fd;
    color: #007aff;
}

.achievements-patents {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
}

.patents-section,
.achievements-section {
    background: #ffffff;
    padding: 2rem;
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.patents-section h3,
.achievements-section h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1d1d1f;
    margin-bottom: 1.5rem;
}

.patent-list,
.achievement-list {
    list-style: none;
    padding: 0;
}

.patent-list li,
.achievement-list li {
    position: relative;
    padding-left: 1.5rem;
    margin-bottom: 1rem;
    font-size: 0.95rem;
    line-height: 1.5;
    color: #515154;
}

.patent-list li::before {
    content: '⚡';
    position: absolute;
    left: 0;
    color: #007aff;
    font-weight: 600;
}

.achievement-list li::before {
    content: '🏆';
    position: absolute;
    left: 0;
    font-weight: 600;
}

/* ===== RESUME DOWNLOAD SECTION ===== */
.resume-download {
    padding: 3rem 0;
    text-align: center;
    background: #f8f9fa;
}

.resume-download .section-header {
    margin-bottom: 0;
}

/* ===== FOOTER ===== */
.footer {
    background: #f2f2f7;
    padding: 1.5rem 0;
    text-align: center;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.footer-content p {
    color: #8e8e93;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.footer-content p:last-child {
    margin-bottom: 0;
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 768px) {
    .nav {
        padding: 0 1rem;
        height: 60px;
    }
    
    .nav-links {
        gap: 1.5rem;
    }
    
    .nav-link {
        font-size: 0.9rem;
    }
    
    .main {
        padding: 0 1rem;
    }
    
    .hero {
        padding: 120px 0 0px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .timeline {
        padding: 60px 0;
    }
    
    .timeline-header {
        margin-bottom: 60px;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .timeline-content::before {
        left: 20px;
    }
    
    .resume-layout {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .resume-sidebar {
        position: static;
        order: 2;
    }
    
    .resume-main {
        order: 1;
    }
    
    .timeline-item {
        padding-left: 60px;
    }
    
    .timeline-marker {
        left: 12px;
        width: 16px;
        height: 16px;
    }
    
    .timeline-card {
        padding: 1.5rem;
    }
    
    .card-title {
        font-size: 1.25rem;
    }
    
    .card-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-title-section {
        gap: 1rem;
    }
    
    .profile-image {
        width: 80px;
        height: 80px;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .timeline-card {
        padding: 1.25rem;
    }
    
    .card-highlights li {
        font-size: 0.9rem;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
    }
    
    .achievements-patents {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .section-header {
        flex-direction: column;
        align-items: stretch;
        text-align: center;
    }
}