/* ===================================
   CSS Variables - Minimalist Theme
   =================================== */

:root {
    /* Color Palette - Minimalist & Professional */
    --bg-primary: #ffffff;
    --bg-secondary: #fafafa;
    --bg-tertiary: #f5f5f5;

    --text-primary: #0a0a0a;
    --text-secondary: #4a4a4a;
    --text-tertiary: #737373;

    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --accent-light: #dbeafe;

    --border: #e5e5e5;
    --border-light: #f0f0f0;

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Courier New', monospace;

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-2xl: 4rem;
    --space-3xl: 6rem;

    /* Effects */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.08);

    --transition: 200ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===================================
   Reset & Base
   =================================== */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    font-size: 16px;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

section {
    padding: var(--space-2xl) 0;
}

/* ===================================
   Typography
   =================================== */

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    color: var(--text-primary);
}

h1 { font-size: 3.5rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.25rem; }

p {
    color: var(--text-secondary);
    line-height: 1.7;
    text-align: justify;
}

strong {
    font-weight: 600;
    color: var(--text-primary);
}

/* ===================================
   Navigation
   =================================== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    transition: var(--transition);
    overflow-x: hidden;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--space-sm);
    padding-bottom: var(--space-sm);
    position: relative;
}

.nav-brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
    font-family: var(--font-mono);
    z-index: 10;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--space-xl);
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9375rem;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: var(--transition);
}

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

.language-selector {
    display: flex;
    gap: 0.25rem;
    margin-left: auto;
}

.lang-btn {
    padding: 0.375rem 0.625rem;
    font-size: 0.75rem;
    font-weight: 600;
    font-family: var(--font-mono);
    color: var(--text-tertiary);
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition);
    text-transform: uppercase;
}

.lang-btn:hover {
    color: var(--text-primary);
    border-color: var(--accent);
}

.lang-btn.active {
    color: var(--bg-primary);
    background: var(--accent);
    border-color: var(--accent);
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
}

.mobile-toggle span {
    width: 22px;
    height: 2px;
    background: var(--text-primary);
    transition: var(--transition);
}

/* ===================================
   Hero Section
   =================================== */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding-top: 80px;
}

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

.hero-greeting {
    font-size: 1.125rem;
    color: var(--text-tertiary);
    margin-bottom: var(--space-sm);
    font-weight: 500;
}

.hero-name {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: var(--space-sm);
    letter-spacing: -0.02em;
}

.hero-title {
    font-size: 2rem;
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: var(--space-lg);
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--space-xl);
    line-height: 1.8;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-xl);
    margin-bottom: var(--space-xl);
    padding: var(--space-lg) 0;
}

.stat {
    text-align: center;
}

.stat-value {
    display: block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
    font-family: var(--font-mono);
}

.stat-label {
    display: block;
    font-size: 0.875rem;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    text-align: center;
}

.hero-actions {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
}

.btn {
    padding: 0.75rem 2rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9375rem;
    transition: var(--transition);
    border: 2px solid transparent;
    cursor: pointer;
    display: inline-block;
}

.btn-primary {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}

.btn-primary:hover {
    background: var(--accent-hover);
    border-color: var(--accent-hover);
    transform: translateY(-1px);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border-color: var(--border);
}

.btn-secondary:hover {
    border-color: var(--text-primary);
    transform: translateY(-1px);
}

/* ===================================
   Section Headers
   =================================== */

.section-header {
    text-align: center;
    margin-bottom: var(--space-2xl);
}

.section-tag {
    display: inline-block;
    font-size: 0.75rem;
    color: var(--accent);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--space-sm);
}

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

/* ===================================
   About Section
   =================================== */

.about {
    background: var(--bg-secondary);
}

.about-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--space-xl);
}

.about-card {
    background: var(--bg-primary);
    padding: var(--space-xl);
    border: 1px solid var(--border);
    border-radius: 8px;
    margin-bottom: var(--space-lg);
}

.about-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--space-md);
    color: var(--text-primary);
}

.about-card p {
    margin-bottom: var(--space-md);
    font-size: 1rem;
    line-height: 1.8;
}

.about-card p:last-child {
    margin-bottom: 0;
}

/* Languages Grid */
.languages-grid {
    display: grid;
    gap: var(--space-sm);
    margin-bottom: var(--space-md);
}

.language-item {
    display: flex;
    justify-content: space-between;
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-secondary);
    border-radius: 6px;
}

.language-name {
    font-weight: 500;
    color: var(--text-primary);
}

.language-level {
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.heritage {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    text-align: center !important;
    padding: var(--space-sm);
}

/* Interests */
.interests-grid {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.interest-tag {
    padding: var(--space-xs) var(--space-md);
    background: var(--bg-secondary);
    border: 1px solid var(--border-light);
    border-radius: 20px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    transition: var(--transition);
}

.interest-tag:hover {
    background: var(--accent-light);
    border-color: var(--accent);
    color: var(--accent);
}

/* Profile Card */
.profile-card {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: var(--space-xl);
    text-align: center;
    margin-bottom: var(--space-lg);
}

.profile-image {
    width: 180px;
    height: 180px;
    margin: 0 auto var(--space-lg);
    border-radius: 50%;
    overflow: hidden;
    border: 3px solid var(--border);
}

.profile-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.profile-info h3 {
    font-size: 1.5rem;
    margin-bottom: var(--space-xs);
}

.profile-role {
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: var(--space-xs);
    text-align: center;
}

.profile-company {
    color: var(--accent);
    font-weight: 600;
    margin-bottom: var(--space-lg);
    text-align: center;
}

.profile-details {
    border-top: 1px solid var(--border-light);
    padding-top: var(--space-md);
}

.detail-item {
    display: flex;
    justify-content: space-between;
    padding: var(--space-sm) 0;
}

.detail-label {
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.detail-value {
    font-weight: 600;
    color: var(--text-primary);
}

/* Mindset Card */
.mindset-card {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: var(--space-xl);
}

.mindset-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--space-md);
}

.mindset-list {
    list-style: none;
}

.mindset-list li {
    padding: var(--space-sm);
    color: var(--text-secondary);
    position: relative;
    padding-left: var(--space-lg);
}

.mindset-list li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--accent);
    font-weight: 600;
}

/* ===================================
   Experience Section
   =================================== */

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

.timeline {
    margin-bottom: var(--space-2xl);
}

.timeline-item {
    border-left: 2px solid var(--border);
    padding-left: var(--space-xl);
    position: relative;
    padding-bottom: var(--space-xl);
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -6px;
    top: 0;
    width: 10px;
    height: 10px;
    background: var(--accent);
    border-radius: 50%;
}

.timeline-date {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    font-family: var(--font-mono);
    margin-bottom: var(--space-sm);
}

.timeline-content h3 {
    font-size: 1.5rem;
    margin-bottom: var(--space-xs);
}

.timeline-content h4 {
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: var(--space-md);
}

.timeline-description {
    margin-bottom: var(--space-md);
    line-height: 1.8;
    text-align: justify;
}

.tech-stack {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.tech-tag {
    padding: var(--space-xs) var(--space-md);
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 0.8125rem;
    font-family: var(--font-mono);
    color: var(--text-secondary);
}

/* Projects */
.projects {
    margin-bottom: var(--space-2xl);
}

.projects h3 {
    font-size: 1.75rem;
    margin-bottom: var(--space-sm);
}

.projects-subtitle {
    color: var(--text-tertiary);
    margin-bottom: var(--space-xl);
    text-align: left;
}

.projects-list {
    display: grid;
    gap: var(--space-xl);
}

.project-group {
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: var(--space-xl);
    background: var(--bg-secondary);
}

.project-group h4 {
    font-size: 1.125rem;
    margin-bottom: var(--space-md);
    color: var(--text-primary);
}

.project-group ul {
    list-style: none;
}

.project-group li {
    padding: var(--space-sm) 0;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-light);
}

.project-group li:last-child {
    border-bottom: none;
}

.project-name {
    font-weight: 600;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.9375rem;
}

/* Additional Work */
.additional-work {
    margin-top: var(--space-xl);
}

.additional-work h4 {
    font-size: 1.25rem;
    margin-bottom: var(--space-md);
}

.work-items {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-md);
}

.work-item {
    padding: var(--space-lg);
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg-secondary);
}

.work-item strong {
    display: block;
    margin-bottom: var(--space-sm);
    font-size: 1rem;
    color: var(--text-primary);
}

.work-item p {
    font-size: 0.9375rem;
    line-height: 1.7;
}

/* Education */
.education {
    margin-top: var(--space-2xl);
    padding-top: var(--space-2xl);
    border-top: 1px solid var(--border);
}

.education h3 {
    font-size: 1.75rem;
    margin-bottom: var(--space-lg);
}

.education-list {
    display: grid;
    gap: var(--space-md);
}

.education-item {
    padding: var(--space-lg);
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg-secondary);
}

.education-item.current {
    border-color: var(--accent);
    background: var(--accent-light);
}

.education-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--space-sm);
}

.education-item h4 {
    font-size: 1.125rem;
    margin-bottom: var(--space-xs);
}

.education-institution {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    text-align: left;
}

.education-period {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    text-align: left;
}

.education-badge {
    padding: var(--space-xs) var(--space-md);
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.education-badge.ongoing {
    background: var(--accent);
    color: white;
}

.education-badge.completed {
    background: var(--bg-tertiary);
    color: var(--text-tertiary);
}

/* ===================================
   Skills Section
   =================================== */

.skills {
    background: var(--bg-secondary);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-lg);
}

.skill-category {
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: var(--space-xl);
}

.skill-category.full-width {
    grid-column: 1 / -1;
}

.skill-category h3 {
    font-size: 1.25rem;
    margin-bottom: var(--space-lg);
    color: var(--text-primary);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    max-height: calc(2 * 2rem + 0.5rem);
}

.skill-tag {
    padding: 0.4rem 0.85rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 0.8125rem;
    font-family: var(--font-mono);
    color: var(--text-secondary);
    transition: var(--transition);
    white-space: nowrap;
}

.skill-tag.primary {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
    font-weight: 600;
}

.skill-tag:hover {
    border-color: var(--accent);
    color: var(--accent);
    transform: translateY(-1px);
}

.skill-tag.primary:hover {
    background: var(--accent-hover);
    color: white;
}

/* Core Competencies */
.expertise-section {
    margin-top: var(--space-md);
}

.expertise-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-xl);
}

.expertise-item {
    text-align: left;
}

.expertise-item h4 {
    font-size: 1.125rem;
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
}

.expertise-item p {
    font-size: 0.9375rem;
    line-height: 1.7;
    color: var(--text-secondary);
}

/* ===================================
   Contact Section
   =================================== */

.contact {
    background: var(--bg-primary);
    text-align: center;
}

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

.contact-text {
    font-size: 1.125rem;
    margin-bottom: var(--space-xl);
    line-height: 1.8;
    text-align: center;
}

.contact-links {
    display: flex;
    justify-content: center;
    gap: var(--space-md);
    flex-wrap: wrap;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    border: 2px solid var(--border);
    border-radius: 6px;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: var(--transition);
}

.contact-link:hover {
    border-color: var(--accent);
    color: var(--accent);
    transform: translateY(-2px);
}

.contact-link svg {
    width: 20px;
    height: 20px;
}

/* ===================================
   Footer
   =================================== */

.footer {
    background: var(--bg-secondary);
    padding: var(--space-xl) 0;
    text-align: center;
    border-top: 1px solid var(--border);
}

.footer p {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    text-align: center;
}

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

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

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

@media (max-width: 768px) {
    :root {
        --space-xl: 2rem;
        --space-2xl: 3rem;
        --space-3xl: 4rem;
    }

    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }

    .hero-name {
        font-size: 2.5rem;
    }

    .hero-title {
        font-size: 1.5rem;
    }

    .navbar .container {
        justify-content: center;
    }

    .language-selector {
        display: none;
    }

    .nav-menu {
        display: none;
    }

    .mobile-toggle {
        display: none;
    }

    .hero-stats {
        flex-direction: column;
        gap: var(--space-lg);
    }

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

    .contact-links {
        flex-direction: column;
    }

    .work-items {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-md);
    }

    .profile-image {
        width: 140px;
        height: 140px;
    }
}