/* ===== CSS Variables ===== */
:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #3b82f6;
    --color-secondary: #0f172a;
    --color-accent: #06b6d4;
    --color-background: #ffffff;
    --color-surface: #f8fafc;
    --color-surface-elevated: #ffffff;
    --color-text: #1e293b;
    --color-text-secondary: #64748b;
    --color-text-muted: #94a3b8;
    --color-border: #e2e8f0;
    --color-success: #10b981;

    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 6rem;

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

    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;
}

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

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

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

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

a:hover {
    color: var(--color-primary-dark);
}

ul {
    list-style: none;
}

/* ===== Container ===== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-secondary);
}

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

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-md);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    margin: var(--spacing-md) auto 0;
    border-radius: var(--radius-full);
}

.section-subtitle {
    text-align: center;
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto var(--spacing-3xl);
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: 0.938rem;
    font-weight: 500;
    border-radius: var(--radius-lg);
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    color: white;
}

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

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

/* ===== 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(--color-border);
    z-index: 1000;
    transition: all var(--transition-base);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-secondary);
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    gap: var(--spacing-xl);
}

.nav-menu a {
    color: var(--color-text-secondary);
    font-weight: 500;
    font-size: 0.938rem;
    position: relative;
    padding: var(--spacing-sm) 0;
}

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

.nav-menu a:hover {
    color: var(--color-primary);
}

.nav-menu a:hover::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-secondary);
    transition: all var(--transition-base);
}

/* ===== Hero Section ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 70px;
    background: linear-gradient(135deg, var(--color-surface) 0%, var(--color-background) 100%);
    position: relative;
    overflow: hidden;
}

.hero-container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-3xl) var(--spacing-lg);
}

.hero-content {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
}

.hero-image {
    position: relative;
}

.profile-photo {
    width: 280px;
    height: 280px;
    border-radius: var(--radius-xl);
    object-fit: cover;
    box-shadow: var(--shadow-xl);
}

.hero-text {
    max-width: 600px;
}

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

.hero-name {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--color-secondary), var(--color-primary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-tagline {
    font-size: 1.25rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
}

.hero-location {
    color: var(--color-text-muted);
    font-size: 0.938rem;
    margin-bottom: var(--spacing-xl);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.hero-location::before {
    content: '';
    display: inline-block;
    width: 8px;
    height: 8px;
    background: var(--color-success);
    border-radius: var(--radius-full);
}

.hero-summary {
    color: var(--color-text);
    margin-bottom: var(--spacing-lg);
    line-height: 1.8;
}

.hero-ai-note {
    color: var(--color-text-secondary);
    font-size: 0.938rem;
    padding-left: var(--spacing-lg);
    border-left: 3px solid var(--color-accent);
    margin-bottom: var(--spacing-xl);
    font-style: italic;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
}

.hero-decoration {
    position: absolute;
    right: -100px;
    bottom: -100px;
    width: 500px;
    height: 500px;
    opacity: 0.1;
    pointer-events: none;
}

.decoration-image {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

/* ===== Experience Section ===== */
.experience {
    padding: var(--spacing-4xl) 0;
    background: var(--color-background);
}

.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, var(--color-primary), var(--color-accent));
}

.timeline-item {
    position: relative;
    padding-left: var(--spacing-2xl);
    padding-bottom: var(--spacing-2xl);
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-marker {
    position: absolute;
    left: -6px;
    top: 4px;
    width: 14px;
    height: 14px;
    border-radius: var(--radius-full);
    background: var(--color-background);
    border: 3px solid var(--color-primary);
    transition: all var(--transition-base);
}

.timeline-marker.current {
    background: var(--color-primary);
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.2);
}

.timeline-item:hover .timeline-marker {
    transform: scale(1.2);
}

.timeline-content {
    background: var(--color-surface-elevated);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
}

.timeline-content:hover {
    box-shadow: var(--shadow-md);
    transform: translateX(4px);
}

.timeline-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.company-logo {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    object-fit: contain;
    background: var(--color-surface);
    padding: 4px;
    flex-shrink: 0;
}

.timeline-header-text {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.timeline-header h3 {
    color: var(--color-secondary);
    margin: 0;
}

.timeline-header .company {
    color: var(--color-primary);
    font-weight: 500;
    font-size: 0.938rem;
}

.timeline-date {
    display: block;
    color: var(--color-text-muted);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-xs);
}

.timeline-location {
    display: block;
    color: var(--color-text-muted);
    font-size: 0.813rem;
    margin-bottom: var(--spacing-md);
}

.timeline-location::before {
    content: '';
    display: inline-block;
    width: 12px;
    height: 12px;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%2394a3b8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M21 10c0 7-9 13-9 13s-9-6-9-13a9 9 0 0 1 18 0z'%3E%3C/path%3E%3Ccircle cx='12' cy='10' r='3'%3E%3C/circle%3E%3C/svg%3E");
    background-size: contain;
    background-repeat: no-repeat;
    margin-right: var(--spacing-xs);
    vertical-align: middle;
}

.timeline-description {
    color: var(--color-text-secondary);
    font-size: 0.938rem;
    line-height: 1.7;
}

/* ===== Skills Section ===== */
.skills {
    padding: var(--spacing-4xl) 0;
    background: var(--color-surface);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-3xl);
}

.skill-category {
    background: var(--color-surface-elevated);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
}

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

.skill-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
}

.skill-icon img {
    width: 24px;
    height: 24px;
    filter: brightness(0) invert(1);
}

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

.skill-category p {
    color: var(--color-text-secondary);
    font-size: 0.938rem;
    margin-bottom: var(--spacing-lg);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.skill-tags li {
    background: var(--color-surface);
    color: var(--color-primary);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.813rem;
    font-weight: 500;
}

.certifications, .languages {
    max-width: 600px;
    margin: var(--spacing-2xl) auto 0;
    text-align: center;
}

.certifications h3, .languages h3 {
    margin-bottom: var(--spacing-lg);
    color: var(--color-text-secondary);
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.cert-badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    color: white;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-full);
    font-weight: 500;
    font-size: 0.938rem;
}

.lang-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-lg);
}

.lang-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
}

.lang-name {
    font-weight: 500;
    color: var(--color-secondary);
}

.lang-level {
    font-size: 0.813rem;
    color: var(--color-text-muted);
}

/* ===== Interests Section ===== */
.interests {
    padding: var(--spacing-4xl) 0;
    background: var(--color-background);
}

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

.interest-card {
    background: var(--color-surface-elevated);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: all var(--transition-base);
}

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

.interest-card.featured {
    grid-column: 1 / -1;
    background: linear-gradient(135deg, var(--color-secondary) 0%, #1e3a5f 100%);
    color: white;
    border: none;
}

.interest-card.featured h3 {
    color: white;
}

.interest-card.featured p {
    color: rgba(255, 255, 255, 0.85);
}

.interest-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
}

.interest-card.featured .interest-icon {
    background: rgba(255, 255, 255, 0.1);
}

.interest-icon img {
    width: 24px;
    height: 24px;
    filter: brightness(0) invert(1);
}

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

.interest-card p {
    color: var(--color-text-secondary);
    font-size: 0.938rem;
    margin-bottom: var(--spacing-md);
}

.interest-quote {
    font-style: italic;
    padding-left: var(--spacing-lg);
    border-left: 3px solid var(--color-accent);
}

.interest-card.featured .interest-quote {
    border-left-color: rgba(255, 255, 255, 0.5);
}

.interest-highlight {
    font-style: italic;
    color: var(--color-primary) !important;
}

.interest-apps {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
}

.interest-apps span {
    background: rgba(255, 255, 255, 0.1);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.813rem;
}

/* ===== Education Section ===== */
.education {
    padding: var(--spacing-3xl) 0;
    background: var(--color-surface);
}

.education-item {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.education-item h3 {
    margin-bottom: var(--spacing-sm);
}

.education-school {
    color: var(--color-primary);
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
}

.education-year {
    color: var(--color-text-muted);
    font-size: 0.938rem;
}

/* ===== Contact Section ===== */
.contact {
    padding: var(--spacing-4xl) 0;
    background: var(--color-background);
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    max-width: 900px;
    margin: 0 auto;
}

.contact-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--spacing-xl);
    background: var(--color-surface-elevated);
    border-radius: var(--radius-xl);
    border: 1px solid var(--color-border);
    text-align: center;
    transition: all var(--transition-base);
    text-decoration: none;
}

.contact-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary);
}

.contact-icon {
    width: 56px;
    height: 56px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
    color: white;
}

.contact-card h3 {
    margin-bottom: var(--spacing-sm);
    font-size: 1rem;
}

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

/* ===== Footer ===== */
.footer {
    padding: var(--spacing-xl) 0;
    background: var(--color-secondary);
    color: rgba(255, 255, 255, 0.7);
    text-align: center;
}

.footer p {
    font-size: 0.875rem;
}

.footer-note {
    margin-top: var(--spacing-sm);
    font-size: 0.813rem;
    color: rgba(255, 255, 255, 0.5);
}

/* ===== Responsive Design ===== */
@media (max-width: 968px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-image {
        display: flex;
        justify-content: center;
    }

    .hero-text {
        max-width: 100%;
    }

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

    .hero-location {
        justify-content: center;
    }

    .hero-ai-note {
        text-align: left;
    }

    .hero-cta {
        justify-content: center;
    }
}

@media (max-width: 768px) {
    html {
        font-size: 15px;
    }

    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: rgba(255, 255, 255, 0.98);
        flex-direction: column;
        padding: var(--spacing-xl);
        gap: var(--spacing-lg);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: all var(--transition-base);
        border-bottom: 1px solid var(--color-border);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -5px);
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }

    .hero-name {
        font-size: 2rem;
    }

    .profile-photo {
        width: 220px;
        height: 220px;
    }

    .timeline::before {
        left: 0;
    }

    .timeline-item {
        padding-left: var(--spacing-xl);
    }

    .timeline-marker {
        left: -5px;
        width: 12px;
        height: 12px;
    }

    .interest-card.featured {
        grid-column: auto;
    }

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

    .btn {
        width: 100%;
    }
}

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

    .hero-name {
        font-size: 1.75rem;
    }

    .timeline-header {
        flex-direction: column;
        gap: var(--spacing-xs);
    }

    .skill-tags {
        justify-content: center;
    }

    .lang-list {
        gap: var(--spacing-md);
    }
}

/* ===== Print Styles ===== */
@media print {
    .navbar,
    .hero-decoration,
    .hero-cta,
    .nav-toggle {
        display: none;
    }

    .hero {
        min-height: auto;
        padding-top: 0;
    }

    body {
        font-size: 12pt;
    }

    .section-title::after {
        display: none;
    }

    .timeline-content,
    .skill-category,
    .interest-card,
    .contact-card {
        box-shadow: none;
        border: 1px solid #ccc;
    }
}