/* ==================== */
/* CSS Variables & Reset */
/* ==================== */
:root {
    --color-bg: #0a0a0a;
    --color-bg-secondary: #111111;
    --color-text: #ffffff;
    --color-text-secondary: #888888;
    --color-accent: #6366f1;
    --color-accent-hover: #818cf8;
    --color-border: #222222;
    --color-success: #22c55e;
    --color-card-bg: #161616;
    --color-skill-bg: rgba(99, 102, 241, 0.1);
    --color-skill-border: rgba(99, 102, 241, 0.3);
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --transition: all 0.3s ease;
}

/* Light Mode */
[data-theme="light"] {
    --color-bg: #ffffff;
    --color-bg-secondary: #f5f5f7;
    --color-text: #1a1a1a;
    --color-text-secondary: #666666;
    --color-accent: #6366f1;
    --color-accent-hover: #4f46e5;
    --color-border: #e5e5e5;
    --color-success: #16a34a;
    --color-card-bg: #ffffff;
    --color-skill-bg: rgba(99, 102, 241, 0.08);
    --color-skill-border: rgba(99, 102, 241, 0.25);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

::selection {
    background-color: var(--color-accent);
    color: var(--color-text);
}

/* ==================== */
/* Container & Layout */
/* ==================== */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
}

.section {
    padding: 100px 0;
    transition: background-color 0.3s ease;
}

.section-title {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 60px;
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 60px;
    height: 3px;
    background: var(--color-accent);
    border-radius: 2px;
}

/* ==================== */
/* Navigation */
/* ==================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(10, 10, 10, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    transition: background 0.3s ease, border-color 0.3s ease;
}

[data-theme="light"] .navbar {
    background: rgba(255, 255, 255, 0.8);
}

.nav-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 24px;
    height: 70px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
    text-decoration: none;
    letter-spacing: -1px;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 40px;
}

.nav-links a {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition);
}

.nav-links a:hover {
    color: var(--color-text);
}

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

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

/* Theme Toggle */
.theme-toggle {
    width: 44px;
    height: 44px;
    border: 1px solid var(--color-border);
    border-radius: 12px;
    background: transparent;
    color: var(--color-text);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    margin-left: 20px;
}

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

.theme-toggle svg {
    width: 20px;
    height: 20px;
}

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

.theme-toggle .moon-icon {
    display: block;
}

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

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

.nav-right {
    display: flex;
    align-items: center;
}

/* ==================== */
/* Hero Section */
/* ==================== */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 120px 24px 60px;
    position: relative;
}

.hero-content {
    max-width: 700px;
}

.hero-greeting {
    color: var(--color-accent);
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: 16px;
    letter-spacing: 1px;
}

.hero-name {
    font-size: clamp(2.5rem, 8vw, 4.5rem);
    font-weight: 700;
    letter-spacing: -2px;
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--color-text) 0%, var(--color-text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-title {
    font-size: clamp(1.2rem, 4vw, 1.8rem);
    font-weight: 400;
    color: var(--color-text-secondary);
    margin-bottom: 24px;
}

.hero-description {
    color: var(--color-text-secondary);
    font-size: 1.1rem;
    max-width: 500px;
    margin: 0 auto 40px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 14px 32px;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 500;
    text-decoration: none;
    transition: var(--transition);
    cursor: pointer;
}

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

.btn-primary:hover {
    background: var(--color-accent-hover);
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    border-color: var(--color-text-secondary);
    transform: translateY(-2px);
}

.hero-scroll {
    position: absolute;
    bottom: 40px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.hero-scroll span {
    font-size: 0.75rem;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 2px;
}

.scroll-indicator {
    width: 24px;
    height: 40px;
    border: 2px solid var(--color-border);
    border-radius: 12px;
    position: relative;
}

.scroll-indicator::before {
    content: '';
    position: absolute;
    top: 8px;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    height: 8px;
    background: var(--color-accent);
    border-radius: 2px;
    animation: scroll 2s infinite;
}

@keyframes scroll {
    0%, 100% { opacity: 1; top: 8px; }
    50% { opacity: 0.5; top: 20px; }
}

/* ==================== */
/* About Section */
/* ==================== */
.about {
    background: var(--color-bg-secondary);
}

.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 60px;
    align-items: start;
}

.about-text p {
    color: var(--color-text-secondary);
    margin-bottom: 20px;
    font-size: 1.05rem;
    line-height: 1.8;
}

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

.about-info {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 30px;
}

.info-item {
    display: flex;
    flex-direction: column;
    padding: 16px 0;
    border-bottom: 1px solid var(--color-border);
}

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

.info-label {
    font-size: 0.8rem;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 4px;
}

.info-value {
    font-weight: 500;
}

.info-value.available {
    color: var(--color-success);
}

/* ==================== */
/* Education Section */
/* ==================== */
.education {
    background: var(--color-bg);
}

/* ==================== */
/* Skills Section */
/* ==================== */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
}

.skill-category {
    background: var(--color-card-bg);
    border: 1px solid var(--color-border);
    border-radius: 16px;
    padding: 28px;
    transition: var(--transition);
}

.skill-category:hover {
    border-color: var(--color-accent);
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(99, 102, 241, 0.1);
}

.skill-category-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
}

.skill-category-icon {
    width: 44px;
    height: 44px;
    background: var(--color-skill-bg);
    border: 1px solid var(--color-skill-border);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-accent);
}

.skill-category-icon svg {
    width: 22px;
    height: 22px;
}

.skill-category h3 {
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--color-text);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.skill-tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    background: var(--color-skill-bg);
    border: 1px solid var(--color-skill-border);
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-text);
    transition: var(--transition);
}

.skill-tag:hover {
    background: var(--color-accent);
    border-color: var(--color-accent);
    color: #ffffff;
    transform: translateY(-2px);
}

.skill-tag.expert::before {
    content: '';
    width: 6px;
    height: 6px;
    background: var(--color-accent);
    border-radius: 50%;
}

.skill-tag:hover::before {
    background: #ffffff;
}

/* ==================== */
/* Experience Section */
/* ==================== */
.experience {
    background: var(--color-bg-secondary);
}

.timeline {
    position: relative;
    padding-left: 40px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 7px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--color-border);
}

.timeline-item {
    position: relative;
    padding-bottom: 50px;
}

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

.timeline-marker {
    position: absolute;
    left: -40px;
    top: 5px;
    width: 16px;
    height: 16px;
    background: var(--color-bg-secondary);
    border: 2px solid var(--color-accent);
    border-radius: 50%;
}

.timeline-content {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 28px;
}

.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 8px;
}

.timeline-header h3 {
    font-size: 1.15rem;
    font-weight: 600;
}

.company {
    color: var(--color-accent);
    font-weight: 500;
}

.timeline-date {
    display: block;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    margin-bottom: 16px;
}

.timeline-content p {
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: 16px;
}

.experience-details p {
    margin-bottom: 16px;
}

.experience-details p strong {
    color: var(--color-text);
}

.timeline-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.timeline-tags span {
    background: var(--color-bg-secondary);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    color: var(--color-text-secondary);
}

/* ==================== */
/* Projects Section */
/* ==================== */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

.project-card {
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    overflow: hidden;
    transition: var(--transition);
}

.project-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-5px);
}

.project-image {
    height: 200px;
    background: linear-gradient(135deg, var(--color-bg) 0%, var(--color-bg-secondary) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-placeholder {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-text-secondary);
}

.project-content {
    padding: 24px;
}

.project-content h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--color-text);
}

.project-content p {
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
    margin-bottom: 16px;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
}

.project-tech span {
    background: var(--color-bg);
    padding: 5px 10px;
    border-radius: 4px;
    font-size: 0.8rem;
    color: var(--color-accent);
}

.project-links {
    display: flex;
    gap: 16px;
}

.project-link {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition);
}

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

/* ==================== */
/* Certificates Section */
/* ==================== */
.certificates {
    background: var(--color-bg);
}

.certificates-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.certificate-card {
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 12px;
    padding: 24px;
    transition: var(--transition);
}

.certificate-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-3px);
}

.certificate-card h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.certificate-card p {
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    margin-bottom: 12px;
}

.certificate-source {
    display: inline-block;
    background: var(--color-bg);
    color: var(--color-accent);
    padding: 4px 10px;
    border-radius: 4px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* ==================== */
/* Contact Section */
/* ==================== */
.contact {
    background: var(--color-bg-secondary);
    text-align: center;
}

.contact-content {
    max-width: 500px;
    margin: 0 auto;
}

.contact-text {
    color: var(--color-text-secondary);
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 30px;
}

.contact-email {
    display: inline-block;
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-text);
    text-decoration: none;
    margin-bottom: 16px;
    transition: var(--transition);
}

.contact-email:hover {
    color: var(--color-accent);
}

.contact-phone {
    color: var(--color-text-secondary);
    font-size: 1.1rem;
    margin-bottom: 40px;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
}

.social-link {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-border);
    border-radius: 50%;
    color: var(--color-text-secondary);
    transition: var(--transition);
}

.social-link:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
    transform: translateY(-3px);
}

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

/* ==================== */
/* Footer */
/* ==================== */
.footer {
    padding: 30px 0;
    text-align: center;
    border-top: 1px solid var(--color-border);
}

.footer p {
    color: var(--color-text-secondary);
    font-size: 0.9rem;
}

/* ==================== */
/* Animations */
/* ==================== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ==================== */
/* Responsive Design */
/* ==================== */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--color-bg);
        flex-direction: column;
        padding: 20px;
        gap: 0;
        border-bottom: 1px solid var(--color-border);
        backdrop-filter: blur(20px);
    }

    [data-theme="light"] .nav-links {
        background: rgba(255, 255, 255, 0.95);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links li {
        padding: 12px 0;
        border-bottom: 1px solid var(--color-border);
    }

    .nav-links li:last-child {
        border-bottom: none;
    }

    .mobile-menu-btn {
        display: flex;
    }

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

    .mobile-menu-btn.active span:nth-child(2) {
        opacity: 0;
    }

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

    .section {
        padding: 70px 0;
    }

    .section-title {
        font-size: 1.6rem;
        margin-bottom: 40px;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .skills-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .skill-category {
        padding: 20px;
    }

    .certificates-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .theme-toggle {
        width: 40px;
        height: 40px;
        margin-left: 12px;
    }

    .nav-right {
        gap: 8px;
    }

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

    .timeline {
        padding-left: 30px;
    }

    .timeline-marker {
        left: -30px;
    }

    .timeline-header {
        flex-direction: column;
    }

    .hero-buttons {
        flex-direction: column;
        width: 100%;
        padding: 0 20px;
    }

    .btn {
        width: 100%;
        text-align: center;
    }
}

@media (max-width: 500px) {
    .skill-tag {
        padding: 6px 12px;
        font-size: 0.85rem;
    }
}