/* 
   Md Fahmid Bin Mostafa - Personal Portfolio
   Color Scheme: Dark Blue and Cyan/Aqua
*/

/* ===== VARIABLES ===== */
:root {
    /* Colors */
    --primary-dark: #0a192f;      /* Dark blue */
    --primary-light: #112240;     /* Lighter dark blue */
    --accent: #64ffda;            /* Cyan/Aqua */
    --accent-light: #a8fff9;      /* Lighter cyan */
    --text-primary: #e6f1ff;      /* Light text */
    --text-secondary: #8892b0;    /* Secondary text */
    --white: #ffffff;
    --black: #000000;
    --gray-light: #f8f9fa;
    --gray: #6c757d;
    --gray-dark: #343a40;
    --success: #28a745;
    --error: #dc3545;

    /* Typography */
    --font-primary: 'Poppins', sans-serif;
    --font-secondary: 'Raleway', sans-serif;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 3rem;
    --spacing-xl: 5rem;
    
    /* Border Radius */
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 16px;
    
    /* Transitions */
    --transition-fast: 0.3s ease;
    --transition-normal: 0.5s ease;
    --transition-slow: 0.8s ease;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 16px 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(--font-primary);
    background-color: var(--primary-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

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

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

ul {
    list-style: none;
}

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

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

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

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

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.underline {
    height: 4px;
    width: 60px;
    background-color: var(--accent);
    margin: 0 auto;
}

.btn {
    display: inline-block;
    padding: 0.8rem 1.8rem;
    border-radius: var(--border-radius-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    font-size: 1rem;
    text-align: center;
}

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

.primary-btn:hover {
    background-color: var(--accent-light);
    color: var(--primary-dark);
    transform: translateY(-3px);
}

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

.secondary-btn:hover {
    background-color: rgba(100, 255, 218, 0.1);
    transform: translateY(-3px);
}

.download-btn {
    background-color: transparent;
    color: var(--white);
    border: 2px solid var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 250px;
    margin-top: 15px;
    margin-left: 3%;
    margin-right: 3%;
}

.download-btn:hover {
    background-color: var(--white);
    color: var(--primary-dark);
    transform: translateY(-3px);
}

.download-btn i {
    font-size: 1rem;
}

.highlight {
    color: var(--accent);
}

/* ===== HEADER ===== */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: rgba(10, 25, 47, 0.9);
    backdrop-filter: blur(10px);
    padding: 1rem 0;
    transition: all var(--transition-fast);
}

header.scrolled {
    box-shadow: var(--shadow-md);
    padding: 0.8rem 0;
}

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

.logo a {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--accent);
    font-family: var(--font-secondary);
}

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

.nav-links li a {
    font-weight: 500;
    position: relative;
    padding: 0.5rem 0;
}

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

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

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

.hamburger span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--accent);
    margin: 5px 0;
    transition: all var(--transition-fast);
}

.close-menu-btn {
    display: none;
    position: absolute;
    top: 20px;
    right: 20px;
    font-size: 24px;
    color: var(--accent);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.close-menu-btn:hover {
    transform: scale(1.1);
}

.hamburger.active {
    position: fixed;
    right: 20px;
}

.hamburger.active::after {
    position: absolute;
    right: 30px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 14px;
    color: var(--accent);
    font-weight: 500;
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 6px);
    background-color: var(--accent);
}

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

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -6px);
    background-color: var(--accent);
}

/* ===== HERO SECTION ===== */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    background-color: var(--primary-dark);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at top right, rgba(100, 255, 218, 0.1), transparent 50%);
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    line-height: 1.2;
}

.hero h2 {
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.hero p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    max-width: 600px;
}

.cta-buttons {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

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

.about-content {
    display: grid;
    grid-template-columns: 3fr 2fr;
    gap: var(--spacing-lg);
    align-items: center;
}

.about-text p {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
}

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

.skills h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

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

.skill-tags span {
    background-color: rgba(100, 255, 218, 0.1);
    color: var(--accent);
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.9rem;
    border: 1px solid var(--accent);
}

.about-image {
    position: relative;
}

.image-container {
    position: relative;
    border-radius: var(--border-radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
    max-width: 350px;
    margin: 0 auto;
    cursor: pointer;
}

.image-container:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
}

.image-container::after {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(100, 255, 218, 0.2);
    mix-blend-mode: screen;
    transition: opacity var(--transition-normal);
}

.image-container:hover::after {
    opacity: 0.5;
}

.image-container img {
    transition: transform var(--transition-normal);
    width: 100%;
    height: auto;
    display: block;
    border-radius: 50%;
}

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

.about-image .image-container {
    border: 2px solid var(--accent);
    padding: 5px;
    border-radius: 50%;
}

.about-image .image-container::after {
    border-radius: 50%;
}

/* ===== SERVICES SECTION ===== */
.services {
    background-color: var(--primary-dark);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

.service-card {
    background-color: var(--primary-light);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-md);
    text-align: center;
    transition: transform var(--transition-fast);
    border: 1px solid transparent;
}

.service-card:hover {
    transform: translateY(-10px);
    border-color: var(--accent);
}

.service-icon {
    font-size: 2.5rem;
    color: var(--accent);
    margin-bottom: var(--spacing-sm);
}

.service-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.service-card p {
    color: var(--text-secondary);
}

/* ===== PORTFOLIO SECTION ===== */
.portfolio {
    background-color: var(--primary-light);
}

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

.portfolio-item {
    position: relative;
    background-color: var(--primary-dark);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-md);
    text-align: center;
    transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
    border: 1px solid transparent;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    height: 100%;
    display: flex;
    flex-direction: column;
}

.portfolio-item:hover {
    transform: translateY(-10px);
    border-color: var(--accent);
    box-shadow: var(--shadow-lg);
    cursor: pointer;
}

.portfolio-image {
    position: relative;
    overflow: hidden;
    height: 200px;
    margin: -1.5rem -1.5rem 1.5rem -1.5rem;
    border-radius: var(--border-radius-md) var(--border-radius-md) 0 0;
}

.portfolio-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-normal);
}

.portfolio-item:hover .portfolio-image img {
    transform: scale(1.05);
}

.portfolio-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(10, 25, 47, 0.75);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.portfolio-overlay .btn {
    background-color: var(--accent);
    color: var(--primary-dark);
    transform: translateY(20px);
    opacity: 0;
    transition: all var(--transition-normal);
    padding: 0.7rem 1.2rem;
    font-weight: 600;
}

.portfolio-item:hover .portfolio-overlay .btn {
    transform: translateY(0);
    opacity: 1;
}

.portfolio-overlay .btn:hover {
    background-color: var(--accent-light);
    transform: translateY(-3px);
}

.portfolio-item h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
    position: relative;
    padding-bottom: var(--spacing-xs);
}

.portfolio-item h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 50px;
    height: 2px;
    background-color: var(--accent);
}

.portfolio-item > p {
    color: var(--accent);
    margin-bottom: var(--spacing-sm);
    font-size: 0.9rem;
}

.portfolio-description {
    margin-bottom: var(--spacing-sm);
    flex-grow: 1;
}

.portfolio-description p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
    margin-bottom: 0;
}

.portfolio-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-top: auto;
}

.portfolio-links .btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 0.6rem 1rem;
    background-color: transparent;
    color: var(--accent);
    border: 1px solid var(--accent);
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
    font-size: 0.9rem;
    flex: 1;
}

.portfolio-links .project-btn {
    background-color: var(--accent);
    color: var(--primary-dark);
    width: 100%;
    font-size: 14px;
}

.portfolio-links .project-btn:hover {
    background-color: var(--accent-light);
    color: var(--primary-dark);
}

.portfolio-links .code-btn:hover {
    background-color: rgba(100, 255, 218, 0.1);
}

.portfolio-links .btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}


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

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

.contact-info h3 {
    font-size: 1.8rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.contact-info p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

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

.contact-item {
    display: flex;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.contact-item i {
    color: var(--accent);
    font-size: 1.2rem;
    margin-right: var(--spacing-sm);
}

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

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: rgba(100, 255, 218, 0.1);
    color: var(--accent);
    transition: all var(--transition-fast);
}

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

.contact-form {
    background-color: var(--primary-dark);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-md);
    box-shadow: var(--shadow-md);
}

.form-group {
    margin-bottom: var(--spacing-sm);
    position: relative;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    background-color: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 1rem;
    transition: border-color var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent);
}

.form-group input.error,
.form-group textarea.error {
    border-color: var(--error);
}

.form-group .error-feedback {
    color: var(--error);
    font-size: 0.85rem;
    margin-top: 5px;
    position: absolute;
    bottom: -20px;
    left: 0;
}

.form-group textarea {
    min-height: 150px;
    resize: vertical;
}

.success-message {
    background-color: rgba(100, 255, 218, 0.1);
    color: var(--accent);
    padding: 1rem;
    border-radius: var(--border-radius-sm);
    margin-top: 1rem;
    text-align: center;
    border: 1px solid var(--accent);
}

.error-message {
    background-color: rgba(220, 53, 69, 0.1);
    color: var(--error);
    padding: 1rem;
    border-radius: var(--border-radius-sm);
    margin-top: 1rem;
    text-align: center;
    border: 1px solid var(--error);
}

.contact-form button[type="submit"] {
    width: 100%;
    margin-top: 1rem;
    cursor: pointer;
}

.contact-form button[type="submit"]:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

/* ===== FOOTER ===== */
footer {
    background-color: var(--primary-dark);
    padding: var(--spacing-md) 0;
    text-align: center;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
}

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

/* ===== BACK TO TOP BUTTON ===== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 40px;
    height: 40px;
    background-color: var(--accent);
    color: var(--primary-dark);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 99;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-md);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

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

/* ===== RESPONSIVE STYLES ===== */
@media screen and (max-width: 992px) {
    html {
        font-size: 15px;
    }
    
    .hero h1 {
        font-size: 3rem;
    }
    
    .hero h2 {
        font-size: 1.8rem;
    }
    
    .about-content {
        grid-template-columns: 1fr;
    }
    
    .about-image {
        order: -1;
        margin-bottom: var(--spacing-md);
    }
    
    .image-container {
        max-width: 400px;
        margin: 0 auto;
    }
}

@media screen and (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 250px;
        height: 100vh;
        background-color: var(--primary-light);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        transition: right var(--transition-normal);
        z-index: 1001;
        box-shadow: var(--shadow-lg);
        padding-top: 60px;
    }
    
    .close-menu-btn {
        display: block;
        position: absolute;
        top: 20px;
        right: 20px;
    }
    
    .nav-links.active {
        right: 0;
    }
    
    .hamburger {
        display: block;
        z-index: 1002;
    }
    
    .hamburger.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 6px);
    }
    
    .hamburger.active span:nth-child(2) {
        opacity: 0;
    }
    
    .hamburger.active span:nth-child(3) {
        transform: rotate(-45deg) translate(5px, -6px);
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero h2 {
        font-size: 1.5rem;
    }
    
    .cta-buttons {
        flex-direction: column;
        gap: var(--spacing-sm);
        width: 100%;
        max-width: 300px;
        margin-left: auto;
        margin-right: auto;
    }
    
    .cta-buttons .btn {
        width: 100%;
        justify-content: center;
    }
    
    .section-header h2 {
        font-size: 2rem;
    }
    
    .portfolio-grid {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    }
    
    .portfolio-links {
        flex-direction: column;
        width: 100%;
    }
    
    .portfolio-item {
        height: 100%;
    }
    
    .portfolio-image {
        height: 180px;
    }
    
    .portfolio-description {
        max-height: 100px;
        overflow-y: auto;
    }
    
    .portfolio-description p {
        font-size: 0.85rem;
    }
    
    .portfolio-item h3 {
        font-size: 1.3rem;
    }
}

@media screen and (max-width: 576px) {
    html {
        font-size: 14px;
    }
    
    .hero h1 {
        font-size: 2.2rem;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
    }
    
    .contact-info {
        margin-bottom: var(--spacing-md);
    }
    
    .portfolio-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .portfolio-item {
        height: 100%;
    }
    
    .portfolio-image {
        height: 160px;
    }
    
    .portfolio-description {
        max-height: 80px;
    }
    
    .hamburger.active::after {
        right: 25px;
        font-size: 12px;
    }
    .download-btn {
        margin: 10px auto;
    }
}