/* ==========================================
   PROFESSIONAL PORTFOLIO - MAIN STYLES
   ========================================== */

/* ==================== CSS VARIABLES ==================== */
:root {
    /* Color Palette - Professional Corporate */
    --primary-blue: #2C3E50;
    --accent-blue: #3498DB;
    --secondary-gray: #34495E;
    --bg-light: #F8F9FA;
    --white: #FFFFFF;
    --text-dark: #333333;
    --text-muted: #7F8C8D;

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;

    /* Spacing (8px base unit) */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    --spacing-xxl: 80px;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.15);

    /* Max Content Width */
    --max-width: 1200px;

    /* Transitions */
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
    overflow-y: auto;
}

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-light);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

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

ul {
    list-style: none;
}

/* ==================== TYPOGRAPHY ==================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--primary-blue);
}

h1 {
    font-size: 2.5rem; /* 40px */
}

h2 {
    font-size: 2rem; /* 32px */
}

h3 {
    font-size: 1.5rem; /* 24px */
}

h4 {
    font-size: 1.25rem; /* 20px */
}

p {
    margin-bottom: var(--spacing-sm);
}

/* ==================== CONTAINER & LAYOUT ==================== */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.content-section {
    padding: 120px var(--spacing-md) var(--spacing-xxl);
    position: relative;
}

/* Desktop: Maintain full viewport height */
@media screen and (min-width: 768px) {
    .content-section {
        min-height: 100vh;
    }
}

/* Mobile: Natural content height */
@media screen and (max-width: 767px) {
    .content-section {
        padding: 80px var(--spacing-sm) var(--spacing-lg);
        min-height: auto;
    }
}

.bg-light {
    background-color: var(--white);
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    font-size: 2.5rem;
    color: var(--primary-blue);
    padding-top: 0;
}

/* ==================== INDEX HEADER ==================== */
.index-header {
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: 0.75rem 1.5rem;
    border-radius: 50px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

@media (max-width: 640px) {
    .index-header {
        top: 10px;
        left: 10px;
        right: 10px;
        padding: 0.6rem 1rem;
    }
}

.header-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    transition: all 0.3s ease;
}

.header-logo-img {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--primary-blue);
}

.header-logo-text {
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--primary-blue);
    transition: color 0.3s ease;
}

.header-logo:hover .header-logo-text {
    color: var(--secondary-gray);
}

/* ==================== NAVIGATION ==================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(44, 62, 80, 0.95);
    backdrop-filter: blur(10px);
    padding: var(--spacing-md) 0;
    z-index: 1000;
    transition: var(--transition);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.navbar.scrolled {
    background-color: var(--primary-blue);
    box-shadow: var(--shadow-sm);
}

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

.nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--white);
}

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

.nav-link {
    color: var(--white);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-blue);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: var(--spacing-sm);
    right: var(--spacing-sm);
    height: 2px;
    background-color: var(--accent-blue);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.nav-link:hover::after,
.nav-link.active::after {
    transform: scaleX(1);
}

/* Hamburger Menu (Mobile) */
.hamburger {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.hamburger-line {
    width: 25px;
    height: 3px;
    background-color: var(--white);
    margin: 3px 0;
    transition: var(--transition);
}

/* ==================== HERO SECTION ==================== */
.hero-section {
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-gray) 100%);
    color: var(--white);
    text-align: center;
    padding: 100px var(--spacing-md) var(--spacing-xxl);
    margin-bottom: 0;
}

/* Desktop: Full viewport */
@media screen and (min-width: 768px) {
    .hero-section {
        min-height: 100vh;
        height: 100vh;
    }
}

/* Mobile: Natural content height */
@media screen and (max-width: 767px) {
    .hero-section {
        min-height: auto;
        height: auto;
        padding: 80px var(--spacing-sm) 3rem;
    }
}

.hero-content {
    max-width: 800px;
    animation: fadeIn 1s ease-in;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.profile-image {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    margin: 0 auto 1rem;
    border: 4px solid var(--white);
    object-fit: cover;
    box-shadow: var(--shadow-md);
}

.hero-name {
    font-size: 3rem;
    margin-bottom: 0.75rem;
    color: var(--white);
}

.hero-title {
    font-size: 1.35rem;
    color: var(--accent-blue);
    margin-bottom: 0.75rem;
    font-weight: 600;
}

.hero-tagline {
    font-size: 1.05rem;
    margin-bottom: 1.5rem;
    color: rgba(255, 255, 255, 0.9);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.5;
}

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

/* ==================== BUTTONS ==================== */
.btn {
    display: inline-block;
    padding: 12px 32px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

@keyframes pulse {
    0% {
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(52, 152, 219, 0.7);
    }
    50% {
        transform: scale(1.05);
        box-shadow: 0 0 20px 10px rgba(52, 152, 219, 0.3);
    }
    100% {
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(52, 152, 219, 0);
    }
}

@keyframes glow {
    0%, 100% {
        box-shadow: 0 0 10px rgba(52, 152, 219, 0.5),
                    0 0 20px rgba(52, 152, 219, 0.3),
                    0 0 30px rgba(52, 152, 219, 0.2);
    }
    50% {
        box-shadow: 0 0 20px rgba(52, 152, 219, 0.8),
                    0 0 30px rgba(52, 152, 219, 0.6),
                    0 0 40px rgba(52, 152, 219, 0.4);
    }
}

.btn-primary {
    background-color: var(--accent-blue);
    color: var(--white);
    position: relative;
    animation: pulse 2s infinite ease-in-out;
    box-shadow: 0 0 20px rgba(52, 152, 219, 0.5);
}

.btn-primary::before {
    content: '';
    position: absolute;
    top: -2px;
    left: -2px;
    right: -2px;
    bottom: -2px;
    background: linear-gradient(45deg, #3498DB, #2980b9, #3498DB);
    border-radius: var(--radius-sm);
    z-index: -1;
    opacity: 0.5;
    animation: glow 2s infinite ease-in-out;
}

.btn-primary:hover {
    background-color: #2980b9;
    transform: translateY(-2px) scale(1.05);
    box-shadow: 0 0 30px rgba(52, 152, 219, 0.8);
    animation: none;
}

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

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

.btn-large {
    padding: 16px 48px;
    font-size: 1.125rem;
}

/* ==================== WORK EXPERIENCE - TIMELINE ==================== */
.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    padding: var(--spacing-md) 0;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 100%;
    background-color: var(--accent-blue);
}

.timeline-item {
    position: relative;
    margin-bottom: var(--spacing-xl);
    padding-left: calc(50% + 40px);
}

.timeline-marker {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background-color: var(--accent-blue);
    border: 4px solid var(--white);
    box-shadow: var(--shadow-sm);
    z-index: 1;
}

.timeline-content {
    background-color: var(--white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

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

.timeline-date {
    display: inline-block;
    background-color: var(--accent-blue);
    color: var(--white);
    padding: 4px 12px;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.job-title {
    color: var(--primary-blue);
    margin-bottom: 4px;
}

.company {
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.achievements {
    margin-top: var(--spacing-md);
}

.achievements li {
    position: relative;
    padding-left: 24px;
    margin-bottom: var(--spacing-sm);
}

.achievements li::before {
    content: '▹';
    position: absolute;
    left: 0;
    color: var(--accent-blue);
    font-size: 1.25rem;
}

/* ==================== PROJECTS GRID ==================== */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.project-card {
    background-color: var(--bg-light);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-md);
}

.project-image {
    position: relative;
    overflow: hidden;
    aspect-ratio: 16 / 10;
    background-color: var(--text-muted);
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.project-card:hover .project-image img {
    transform: scale(1.05);
}

.project-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(44, 62, 80, 0.9);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.project-card:hover .project-overlay {
    opacity: 1;
}

.overlay-link {
    color: var(--white);
    background-color: var(--accent-blue);
    padding: 10px 24px;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

.overlay-link:hover {
    background-color: #2980b9;
}

.project-info {
    padding: var(--spacing-lg);
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.project-title {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-sm);
}

.project-description {
    color: var(--text-dark);
    margin-bottom: var(--spacing-md);
    flex-grow: 1;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.tech-tag {
    background-color: rgba(52, 152, 219, 0.1);
    color: var(--accent-blue);
    padding: 4px 12px;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 600;
}

/* ==================== SKILLS SECTION ==================== */
#skills {
    background-color: var(--bg-light);
    padding-top: 100px;
}

#skills .section-title {
    margin-bottom: var(--spacing-xl);
    margin-top: 0;
}

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

.skill-category {
    background-color: var(--white);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

.category-title {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-sm);
    font-size: 1.25rem;
    border-bottom: 2px solid var(--accent-blue);
    padding-bottom: var(--spacing-sm);
}

.category-subtitle {
    color: var(--gray);
    font-size: 0.9rem;
    font-style: italic;
    margin-bottom: var(--spacing-md);
    line-height: 1.4;
}

.leadership-category .category-title {
    color: var(--primary-blue);
    border-bottom-color: var(--primary-blue);
}

.technical-category .category-title {
    color: var(--accent-blue);
    border-bottom-color: var(--accent-blue);
}

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

.skill-tag {
    background-color: var(--bg-light);
    color: var(--primary-blue);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
    border: 2px solid var(--accent-blue);
    transition: var(--transition);
}

.skill-tag:hover {
    background-color: var(--accent-blue);
    color: var(--white);
    transform: scale(1.05);
}

/* ==================== EDUCATION & CERTIFICATIONS ==================== */
.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.education-card {
    background-color: var(--bg-light);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    text-align: center;
    transition: var(--transition);
}

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

.education-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.degree,
.cert-name {
    color: var(--primary-blue);
    margin-bottom: var(--spacing-sm);
    font-size: 1.125rem;
}

.institution,
.cert-issuer {
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.edu-date {
    color: var(--accent-blue);
    font-weight: 600;
    font-size: 0.875rem;
}

/* ==================== CONTACT SECTION ==================== */
.contact-section {
    background: linear-gradient(135deg, var(--primary-blue) 0%, var(--secondary-gray) 100%);
    color: var(--white);
}

.contact-section .section-title {
    color: var(--white);
}

.contact-intro {
    text-align: center;
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.contact-methods {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.contact-card {
    background-color: rgba(255, 255, 255, 0.1);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    transition: var(--transition);
    border: 2px solid transparent;
}

.contact-card:hover {
    background-color: rgba(255, 255, 255, 0.2);
    border-color: var(--accent-blue);
    transform: translateY(-4px);
}

.contact-icon {
    font-size: 2.5rem;
}

.contact-label {
    font-weight: 700;
    font-size: 1.125rem;
}

.contact-value {
    color: var(--accent-blue);
    font-weight: 600;
}

.resume-download {
    text-align: center;
    margin-top: var(--spacing-xl);
}

/* ==================== FOOTER ==================== */
.site-footer {
    background-color: var(--primary-blue);
    color: var(--white);
    text-align: center;
    padding: var(--spacing-xxl) var(--spacing-lg);
    margin-top: auto;
}

.site-footer p {
    margin: 0;
}

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

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