/* 
* Main Stylesheet for MD TOFIQ AKBAR's Portfolio
* Author: Manus AI
* Version: 1.0
*/

/* ===== VARIABLES ===== */
:root {
    /* Colors */
    --primary-color: #2563EB;
    --secondary-color: #10B981;
    --dark-color: #1E293B;
    --light-color: #F8FAFC;
    --neutral-color: #64748B;
    --neutral-light: #CBD5E1;
    --neutral-dark: #334155;
    --white: #FFFFFF;
    --black: #000000;
    --gray-100: #F1F5F9;
    --gray-200: #E2E8F0;
    --gray-300: #CBD5E1;
    
    /* Typography */
    --heading-font: 'Poppins', sans-serif;
    --body-font: 'Open Sans', sans-serif;
    --code-font: 'Fira Code', monospace;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;
    
    /* Border Radius */
    --border-radius-sm: 0.25rem;
    --border-radius-md: 0.5rem;
    --border-radius-lg: 1rem;
    --border-radius-full: 50%;
    
    /* Transitions */
    --transition-fast: 0.3s ease;
    --transition-medium: 0.5s ease;
    --transition-slow: 0.8s ease;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

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

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

body {
    font-family: var(--body-font);
    line-height: 1.6;
    color: var(--dark-color);
    background-color: var(--light-color);
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--heading-font);
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: var(--spacing-md);
    color: var(--dark-color);
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.25rem;
}

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

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

a:hover {
    color: var(--secondary-color);
}

ul {
    list-style: none;
}

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

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

.section {
    padding: var(--spacing-xxl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xxl);
}

.section-divider {
    height: 4px;
    width: 60px;
    background-color: var(--primary-color);
    margin: 0 auto;
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius-md);
    font-weight: 500;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    font-family: var(--heading-font);
}

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

.btn-primary:hover {
    background-color: #1d4ed8;
    color: var(--white);
}

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

.btn-secondary:hover {
    background-color: #059669;
    color: var(--white);
}

/* ===== HEADER & NAVIGATION ===== */
#header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--white);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    padding: var(--spacing-md) 0;
    transition: all var(--transition-fast);
}

#header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo h1 {
    font-size: 1.5rem;
    margin-bottom: 0;
    color: var(--primary-color);
}

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

.nav-menu li {
    margin-left: var(--spacing-lg);
}

.nav-link {
    color: var(--dark-color);
    font-weight: 500;
    position: relative;
    padding: var(--spacing-xs) 0;
}

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

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

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

.hamburger {
    display: none;
    cursor: pointer;
}

.bar {
    display: block;
    width: 25px;
    height: 3px;
    margin: 5px auto;
    background-color: var(--dark-color);
    transition: all var(--transition-fast);
}

/* ===== HERO SECTION ===== */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    background-color: var(--light-color);
    position: relative;
    padding-top: 80px;
}

.hero-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.hero-text {
    flex: 1;
    padding-right: var(--spacing-xl);
}

.hero-text h1 {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
    color: var(--dark-color);
}

.hero-text h2 {
    font-size: 1.75rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.hero-text p {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xl);
    color: var(--neutral-dark);
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.social-links {
    display: flex;
    gap: var(--spacing-md);
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-full);
    background-color: var(--primary-color);
    color: var(--white);
    transition: all var(--transition-fast);
}

.social-links a:hover {
    background-color: var(--secondary-color);
    transform: translateY(-3px);
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.profile-image {
    width: 300px;
    height: 300px;
    border-radius: var(--border-radius-full);
    overflow: hidden;
    border: 5px solid var(--white);
    box-shadow: var(--shadow-lg);
}

.profile-placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--gray-200);
    color: var(--neutral-color);
}

.profile-placeholder i {
    font-size: 6rem;
}

.scroll-down {
    position: absolute;
    bottom: var(--spacing-xl);
    left: 50%;
    transform: translateX(-50%);
    animation: bounce 2s infinite;
}

.scroll-down a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-full);
    background-color: var(--white);
    color: var(--primary-color);
    box-shadow: var(--shadow-md);
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0) translateX(-50%);
    }
    40% {
        transform: translateY(-20px) translateX(-50%);
    }
    60% {
        transform: translateY(-10px) translateX(-50%);
    }
}

/* ===== ABOUT SECTION ===== */
.about {
    background-color: var(--white);
}

.about-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.about-text {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.about-info {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--spacing-xl);
}

.info-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.info-item i {
    font-size: 1.5rem;
    color: var(--primary-color);
}

/* ===== SKILLS SECTION ===== */
.skills {
    background-color: var(--gray-100);
}

.skills-content {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

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

.skill-category:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.skill-category h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--gray-200);
}

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

.skill-tag {
    background-color: var(--primary-color);
    color: var(--white);
    padding: 0.25rem 0.75rem;
    border-radius: var(--border-radius-full);
    font-size: 0.9rem;
    font-family: var(--code-font);
}

/* ===== EXPERIENCE SECTION ===== */
.experience {
    background-color: var(--white);
}

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

.timeline::after {
    content: '';
    position: absolute;
    width: 4px;
    background-color: var(--gray-200);
    top: 0;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
}

.timeline-item {
    position: relative;
    width: 50%;
    padding: 0 var(--spacing-xl);
    margin-bottom: var(--spacing-xxl);
}

.timeline-item:nth-child(odd) {
    left: 0;
}

.timeline-item:nth-child(even) {
    left: 50%;
}

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

.timeline-content::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    background-color: var(--white);
    border: 4px solid var(--primary-color);
    border-radius: var(--border-radius-full);
    top: 20px;
    z-index: 1;
}

.timeline-item:nth-child(odd) .timeline-content::after {
    right: -50px;
}

.timeline-item:nth-child(even) .timeline-content::after {
    left: -50px;
}

.timeline-period {
    display: inline-block;
    background-color: var(--primary-color);
    color: var(--white);
    padding: 0.25rem 0.75rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
}

.timeline-company {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xs);
    color: var(--dark-color);
}

.timeline-position {
    font-size: 1rem;
    color: var(--neutral-dark);
    margin-bottom: var(--spacing-md);
}

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

.timeline-responsibilities li {
    position: relative;
    padding-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.timeline-responsibilities li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 8px;
    height: 8px;
    border-radius: var(--border-radius-full);
    background-color: var(--secondary-color);
}

/* ===== PROJECTS SECTION ===== */
.projects {
    background-color: var(--gray-100);
}

.project-filters {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
}

.filter-btn {
    background-color: var(--white);
    color: var(--dark-color);
    border: 1px solid var(--gray-200);
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius-full);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.filter-btn:hover, .filter-btn.active {
    background-color: var(--primary-color);
    color: var(--white);
    border-color: var(--primary-color);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.project-card {
    background-color: var(--white);
    border-radius: var(--border-radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-fast);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.project-image {
    height: 180px;
    background-color: var(--gray-200);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--neutral-color);
}

.project-image i {
    font-size: 3rem;
}

.project-details {
    padding: var(--spacing-lg);
}

.project-title {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.project-description {
    margin-bottom: var(--spacing-md);
    color: var(--neutral-dark);
}

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

.tech-tag {
    background-color: var(--gray-200);
    color: var(--neutral-dark);
    padding: 0.15rem 0.5rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.8rem;
    font-family: var(--code-font);
}

/* ===== EDUCATION SECTION ===== */
.education {
    background-color: var(--white);
}

.education-content {
    max-width: 600px;
    margin: 0 auto;
}

.education-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-lg);
}

.education-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 60px;
    height: 60px;
    border-radius: var(--border-radius-full);
    background-color: var(--primary-color);
    color: var(--white);
    flex-shrink: 0;
}

.education-icon i {
    font-size: 1.5rem;
}

.education-details h3 {
    margin-bottom: var(--spacing-xs);
}

.education-details h4 {
    color: var(--neutral-dark);
    margin-bottom: var(--spacing-xs);
}

.education-details p {
    color: var(--neutral-color);
}

/* ===== CONTACT SECTION ===== */
.contact {
    background-color: var(--gray-100);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.contact-item i {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.contact-item h3 {
    margin-bottom: var(--spacing-xs);
}

.contact-social {
    margin-top: var(--spacing-xl);
}

.contact-social h3 {
    margin-bottom: var(--spacing-md);
}

.form-group {
    margin-bottom: var(--spacing-md);
}

input, textarea {
    width: 100%;
    padding: var(--spacing-md);
    border: 1px solid var(--gray-300);
    border-radius: var(--border-radius-md);
    font-family: var(--body-font);
    transition: border-color var(--transition-fast);
}

input:focus, textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* ===== FOOTER ===== */
#footer {
    background-color: var(--dark-color);
    color: var(--white);
    padding: var(--spacing-lg) 0;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.back-to-top a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-full);
    background-color: var(--primary-color);
    color: var(--white);
    transition: all var(--transition-fast);
}

.back-to-top a:hover {
    background-color: var(--secondary-color);
    transform: translateY(-3px);
}

/* ===== RESPONSIVE STYLES ===== */
@media (max-width: 1024px) {
    html {
        font-size: 14px;
    }
    
    .hero-content {
        flex-direction: column-reverse;
        text-align: center;
    }
    
    .hero-text {
        padding-right: 0;
        margin-top: var(--spacing-xl);
    }
    
    .hero-buttons {
        justify-content: center;
    }
    
    .social-links {
        justify-content: center;
    }
    
    .timeline::after {
        left: 40px;
    }
    
    .timeline-item {
        width: 100%;
        padding-left: 80px;
        padding-right: 0;
    }
    
    .timeline-item:nth-child(even) {
        left: 0;
    }
    
    .timeline-item:nth-child(odd) .timeline-content::after,
    .timeline-item:nth-child(even) .timeline-content::after {
        left: -40px;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .hamburger {
        display: block;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
        padding: var(--spacing-lg) 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-menu li {
        margin: var(--spacing-md) 0;
    }
    
    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }
    
    .hamburger.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }
    
    .hamburger.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }
    
    .skills-content {
        grid-template-columns: 1fr;
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-text h1 {
        font-size: 2.5rem;
    }
    
    .hero-text h2 {
        font-size: 1.5rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .project-filters {
        flex-direction: column;
        align-items: center;
    }
    
    .filter-btn {
        width: 100%;
        max-width: 200px;
    }
    
    .footer-content {
        flex-direction: column;
        gap: var(--spacing-md);
    }
}