/* ============================================
   CSS Variables & Base Styles
   ============================================ */
:root {
    --primary-color: #2E86AB;
    --secondary-color: #06A77D;
    --accent-color: #06A77D;
    --bg-primary: #FFFFFF;
    --bg-secondary: #F8F9FA;
    --bg-tertiary: #F0F2F5;
    --text-primary: #1A1A1A;
    --text-secondary: #4A4A4A;
    --text-light: #6B6B6B;
    --border-color: #E0E0E0;
    --grid-color: #E8E8E8;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

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

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 24px;
}

.nav-brand {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
    letter-spacing: 1px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 15px;
    transition: var(--transition);
    position: relative;
}

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

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

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

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.hamburger span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: var(--transition);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background: var(--bg-primary);
    padding-top: 80px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    opacity: 0.3;
    z-index: 0;
}

#gridCanvas {
    width: 100%;
    height: 100%;
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 800px;
    padding: 40px 24px;
    animation: fadeInUp 0.8s ease-out;
}

.hero-name {
    font-size: 64px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 16px;
    letter-spacing: -1px;
}

.hero-tagline {
    font-size: 24px;
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 24px;
}

.hero-intro {
    font-size: 18px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 40px;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

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

.btn {
    padding: 14px 32px;
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    border-radius: 6px;
    transition: var(--transition);
    display: inline-block;
    border: 2px solid transparent;
    cursor: pointer;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    background: #256A8A;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

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

.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1;
}

.scroll-line {
    width: 2px;
    height: 40px;
    background: linear-gradient(to bottom, var(--primary-color), transparent);
    animation: scrollPulse 2s infinite;
}

/* ============================================
   Section Styles
   ============================================ */
section {
    padding: 100px 0;
    position: relative;
}

.section-title {
    font-size: 42px;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    margin-bottom: 16px;
    position: relative;
    display: inline-block;
    width: 100%;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: var(--accent-color);
    border-radius: 2px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    font-size: 18px;
    margin-bottom: 60px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

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

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

.about-text {
    font-size: 17px;
    color: var(--text-secondary);
    line-height: 1.9;
}

.about-text p {
    margin-bottom: 20px;
}

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

.about-highlight {
    background: var(--bg-tertiary);
    padding: 20px;
    border-left: 4px solid var(--accent-color);
    border-radius: 4px;
    margin-top: 24px;
    font-style: italic;
    color: var(--text-secondary);
}

.about-stats {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.stat-card {
    background: white;
    padding: 32px;
    border-radius: 8px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--accent-color);
}

.stat-number {
    font-size: 36px;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 8px;
}

.stat-label {
    font-size: 14px;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* ============================================
   Skills Section
   ============================================ */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
    margin-top: 60px;
}

.skill-category {
    background: white;
    padding: 32px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.skill-category:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--accent-color);
}

.skill-category-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.skill-category-title i {
    color: var(--primary-color);
    font-size: 24px;
}

.beginner-badge {
    background: var(--accent-color);
    color: white;
    font-size: 12px;
    padding: 4px 10px;
    border-radius: 12px;
    font-weight: 500;
    margin-left: auto;
}

.skill-items {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.skill-item {
    background: var(--bg-secondary);
    padding: 10px 18px;
    border-radius: 6px;
    font-size: 14px;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.skill-item:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

/* ============================================
   Projects Section
   ============================================ */
.projects {
    background: var(--bg-secondary);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
    margin-top: 60px;
}

.project-card {
    background: white;
    padding: 32px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.project-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-color);
}

.project-header {
    margin-bottom: 16px;
}

.project-title {
    font-size: 22px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.project-tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

.tag {
    padding: 6px 12px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.tag-robotics {
    background: rgba(46, 134, 171, 0.1);
    color: var(--primary-color);
}

.tag-embedded {
    background: rgba(6, 167, 125, 0.1);
    color: var(--accent-color);
}

.tag-iot {
    background: rgba(46, 134, 171, 0.15);
    color: var(--primary-color);
}

.project-description {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 16px;
    flex-grow: 1;
}

.project-tech {
    font-size: 14px;
    color: var(--text-light);
    margin-bottom: 16px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.project-tech strong {
    color: var(--text-primary);
}

.project-achievement {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--accent-color);
    font-size: 14px;
    font-weight: 500;
    margin-top: auto;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.project-achievement i {
    font-size: 16px;
}

/* ============================================
   Activities Section
   ============================================ */
.activities-timeline {
    max-width: 800px;
    margin: 60px auto 0;
    position: relative;
    padding-left: 40px;
}

.activities-timeline::before {
    content: '';
    position: absolute;
    left: 8px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--grid-color);
}

.timeline-item {
    position: relative;
    margin-bottom: 48px;
    padding-left: 40px;
}

.timeline-marker {
    position: absolute;
    left: -32px;
    top: 4px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: white;
    border: 3px solid var(--accent-color);
    box-shadow: 0 0 0 4px var(--bg-secondary);
}

.timeline-content {
    background: white;
    padding: 24px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.timeline-content:hover {
    transform: translateX(8px);
    box-shadow: var(--shadow-md);
    border-color: var(--accent-color);
}

.timeline-title {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

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

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

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 60px;
    margin-top: 60px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.contact-item {
    display: flex;
    gap: 20px;
    align-items: start;
}

.contact-item i {
    font-size: 24px;
    color: var(--primary-color);
    margin-top: 4px;
    min-width: 30px;
}

.contact-item h4 {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.contact-item a,
.contact-item p {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

.contact-item a:hover {
    color: var(--primary-color);
}

.contact-form {
    background: white;
    padding: 40px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.form-group {
    margin-bottom: 24px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 14px 16px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 15px;
    font-family: inherit;
    transition: var(--transition);
    background: var(--bg-secondary);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    background: white;
    box-shadow: 0 0 0 3px rgba(46, 134, 171, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background: var(--bg-tertiary);
    padding: 32px 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

.footer p {
    color: var(--text-light);
    font-size: 14px;
}

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

@keyframes scrollPulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.3;
    }
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 968px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        right: -100%;
        flex-direction: column;
        background: white;
        width: 250px;
        padding: 24px;
        box-shadow: var(--shadow-lg);
        transition: var(--transition);
        border-left: 1px solid var(--border-color);
    }

    .nav-menu.active {
        right: 0;
    }

    .hamburger {
        display: flex;
    }

    .hero-name {
        font-size: 48px;
    }

    .hero-tagline {
        font-size: 20px;
    }

    .hero-intro {
        font-size: 16px;
    }

    .section-title {
        font-size: 36px;
    }

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

    .about-stats {
        flex-direction: row;
        justify-content: space-around;
    }

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

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

@media (max-width: 640px) {
    .hero-name {
        font-size: 36px;
    }

    .hero-tagline {
        font-size: 18px;
    }

    .section-title {
        font-size: 32px;
    }

    .btn {
        padding: 12px 24px;
        font-size: 14px;
    }

    .stat-card {
        padding: 24px;
    }

    .stat-number {
        font-size: 28px;
    }

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

    .about-stats {
        flex-direction: column;
    }

    .contact-form {
        padding: 24px;
    }

    .activities-timeline {
        padding-left: 24px;
    }

    .timeline-item {
        padding-left: 32px;
    }
}

/* ============================================
   Scroll Animations (will be enhanced by JS)
   ============================================ */
.fade-in {
    animation: fadeInUp 0.6s ease-out;
}