/* CSS Variables */
:root {
    --color-primary: #0a4d68;
    --color-primary-light: #088395;
    --color-accent: #05bfdb;
    --color-text: #2d3748;
    --color-text-light: #4a5568;
    --color-bg: #f7fafc;
    --color-bg-white: #ffffff;
    --color-border: #e2e8f0;
    --color-shadow: rgba(10, 77, 104, 0.1);
    --color-shadow-hover: rgba(10, 77, 104, 0.2);
    
    --font-primary: 'Poppins', sans-serif;
    
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --transition: all 0.3s ease;
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    overflow-x: hidden;
}

/* Utility Classes */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 600;
    color: var(--color-primary);
    text-align: center;
    margin-bottom: var(--spacing-xl);
    opacity: 0;
    animation: fadeInUp 0.6s ease forwards;
}

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

/* Header & Navigation */
.header {
    background-color: var(--color-bg-white);
    box-shadow: 0 2px 10px var(--color-shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
}

.nav-brand a {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-primary);
    text-decoration: none;
    transition: var(--transition);
}

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

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

.nav-link {
    color: var(--color-text);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-primary);
    transition: var(--transition);
}

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

.nav-link:hover,
.nav-link:focus-visible {
    color: var(--color-primary);
    outline: none;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
    gap: 4px;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background-color: var(--color-primary);
    transition: var(--transition);
    border-radius: 2px;
}

.nav-toggle:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Hero Section */
.hero {
    padding: var(--spacing-2xl) var(--spacing-md);
    background: linear-gradient(135deg, var(--color-bg-white) 0%, var(--color-bg) 100%);
    min-height: 90vh;
    display: flex;
    align-items: center;
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.hero-content {
    opacity: 0;
    animation: fadeInUp 0.8s ease 0.2s forwards;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--color-primary-light);
    margin-bottom: var(--spacing-md);
    font-weight: 500;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
    max-width: 600px;
}

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

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    animation: fadeInUp 0.8s ease 0.4s forwards;
}

.profile-photo {
    width: 300px;
    height: 300px;
    border-radius: 50%;
    object-fit: cover;
    object-position: center;
    border: 5px solid var(--color-accent);
    box-shadow: 0 10px 30px var(--color-shadow);
    transition: var(--transition);
    display: block;
}

.profile-photo:hover {
    transform: scale(1.05);
    box-shadow: 0 15px 40px var(--color-shadow-hover);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    border-radius: var(--border-radius);
    transition: var(--transition);
    cursor: pointer;
    border: none;
    font-family: var(--font-primary);
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    color: white;
    box-shadow: 0 4px 15px var(--color-shadow);
}

.btn-primary:hover,
.btn-primary:focus-visible {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--color-shadow-hover);
    outline: none;
}

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

.btn-secondary:hover,
.btn-secondary:focus-visible {
    background-color: var(--color-primary);
    color: white;
    outline: none;
}

/* About Section */
.about {
    padding: var(--spacing-2xl) var(--spacing-md);
    background-color: var(--color-bg-white);
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    opacity: 0;
    animation: fadeInUp 0.6s ease 0.3s forwards;
}

.about-content p {
    margin-bottom: var(--spacing-md);
    color: var(--color-text-light);
    font-size: 1.05rem;
}

/* Skills Section */
.skills {
    padding: var(--spacing-2xl) var(--spacing-md);
    background-color: var(--color-bg);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    opacity: 0;
    animation: fadeInUp 0.6s ease 0.3s forwards;
}

.skill-item {
    background-color: var(--color-bg-white);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    box-shadow: 0 4px 15px var(--color-shadow);
    transition: var(--transition);
    text-align: center;
}

.skill-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px var(--color-shadow-hover);
}

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

.skill-name {
    font-size: 1.25rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
}

.skill-bar {
    width: 100%;
    height: 8px;
    background-color: var(--color-border);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: var(--spacing-xs);
}

.skill-level {
    height: 100%;
    background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-accent) 100%);
    border-radius: 4px;
    transition: width 1s ease;
}

.skill-label {
    font-size: 0.875rem;
    color: var(--color-text-light);
    font-weight: 500;
}

/* Projects Section */
.projects {
    padding: var(--spacing-2xl) var(--spacing-md);
    background-color: var(--color-bg-white);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    opacity: 0;
    animation: fadeInUp 0.6s ease 0.3s forwards;
}

.project-card {
    background-color: var(--color-bg);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    box-shadow: 0 4px 15px var(--color-shadow);
    transition: var(--transition);
    border: 1px solid var(--color-border);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px var(--color-shadow-hover);
    border-color: var(--color-primary-light);
}

.project-title {
    font-size: 1.5rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.project-description {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
}

.tag {
    background-color: var(--color-primary-light);
    color: white;
    padding: 0.25rem var(--spacing-sm);
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
}

.project-link {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    display: inline-block;
}

.project-link:hover,
.project-link:focus-visible {
    color: var(--color-primary-light);
    transform: translateX(5px);
    outline: none;
}

/* Contact Section */
.contact {
    padding: var(--spacing-2xl) var(--spacing-md);
    background-color: var(--color-bg);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    max-width: 1000px;
    margin: 0 auto;
    opacity: 0;
    animation: fadeInUp 0.6s ease 0.3s forwards;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.contact-item {
    font-size: 1.1rem;
}

.contact-item strong {
    display: block;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

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

.contact-item a:hover,
.contact-item a:focus-visible {
    color: var(--color-primary);
    outline: none;
}

.contact-form {
    background-color: var(--color-bg-white);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    box-shadow: 0 4px 15px var(--color-shadow);
}

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

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    color: var(--color-primary);
    font-weight: 500;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-sm);
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius);
    font-family: var(--font-primary);
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(10, 77, 104, 0.1);
}

.form-group input:invalid:not(:placeholder-shown),
.form-group textarea:invalid:not(:placeholder-shown) {
    border-color: #e53e3e;
}

/* Footer */
.footer {
    background-color: var(--color-primary);
    color: white;
    padding: var(--spacing-lg) var(--spacing-md);
    text-align: center;
}

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

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

.footer-nav a {
    color: white;
    text-decoration: none;
    transition: var(--transition);
}

.footer-nav a:hover,
.footer-nav a:focus-visible {
    color: var(--color-accent);
    outline: none;
}

.footer-note {
    font-size: 0.9rem;
    opacity: 0.9;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--color-primary);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--border-radius);
    box-shadow: 0 4px 15px var(--color-shadow-hover);
    opacity: 0;
    transform: translateY(20px);
    transition: var(--transition);
    z-index: 2000;
    max-width: 300px;
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
}

/* Responsive Design */

/* Tablet (768px and below) */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        flex-direction: column;
        background-color: var(--color-bg-white);
        width: 100%;
        text-align: center;
        transition: var(--transition);
        box-shadow: 0 10px 27px var(--color-shadow);
        padding: var(--spacing-lg) 0;
        gap: var(--spacing-md);
    }

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

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(8px, 8px);
    }

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

    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -7px);
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.25rem;
    }

    .hero-image {
        order: -1;
    }

    .profile-photo {
        width: 200px;
        height: 200px;
    }

    .section-title {
        font-size: 2rem;
    }

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

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

/* Mobile (480px and below) */
@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }

    .hero {
        padding: var(--spacing-xl) var(--spacing-sm);
        min-height: auto;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.1rem;
    }

    .hero-description {
        font-size: 1rem;
    }

    .hero-cta {
        flex-direction: column;
    }

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

    .section-title {
        font-size: 1.75rem;
    }

    .about,
    .skills,
    .projects,
    .contact {
        padding: var(--spacing-xl) var(--spacing-sm);
    }

    .profile-photo {
        width: 150px;
        height: 150px;
    }

    .toast {
        right: 10px;
        left: 10px;
        max-width: none;
    }
}

/* Large Desktop (1024px and above) */
@media (min-width: 1024px) {
    .hero-container {
        gap: var(--spacing-2xl);
    }

    .skills-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    .projects-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}