/* Root Variables for Theme */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --accent-color: #0066cc;
    --accent-hover: #0052a3;
    --border-color: #dee2e6;
    --shadow: rgba(0, 0, 0, 0.1);
    --card-bg: #ffffff;
    --header-bg: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --nav-bg: #ffffff;
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --text-primary: #eee;
    --text-secondary: #adb5bd;
    --accent-color: #4da6ff;
    --accent-hover: #6bb6ff;
    --border-color: #2d3748;
    --shadow: rgba(0, 0, 0, 0.3);
    --card-bg: #16213e;
    --header-bg: linear-gradient(135deg, #434343 0%, #000000 100%);
    --nav-bg: #16213e;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: var(--transition);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Theme Toggle Button */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
}

#themeToggle {
    background-color: var(--card-bg);
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    transition: var(--transition);
    box-shadow: 0 2px 8px var(--shadow);
}

#themeToggle:hover {
    transform: scale(1.1);
    box-shadow: 0 4px 12px var(--shadow);
}

.toggle-icon {
    transition: var(--transition);
}

/* Header */
header {
    background: var(--header-bg);
    color: white;
    padding: 80px 0 60px;
    text-align: center;
    margin-bottom: 0;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
}

header .subtitle {
    font-size: 1.3rem;
    opacity: 0.95;
    font-weight: 300;
}

/* Navigation */
nav {
    background-color: var(--nav-bg);
    box-shadow: 0 2px 8px var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: var(--transition);
}

.nav-links {
    list-style: none;
    display: flex;
    justify-content: center;
    padding: 0;
    margin: 0;
}

.nav-links li {
    margin: 0;
}

.nav-links a {
    display: block;
    padding: 20px 30px;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    border-bottom: 3px solid transparent;
}

.nav-links a:hover {
    color: var(--accent-color);
    border-bottom-color: var(--accent-color);
    background-color: var(--bg-secondary);
}

/* Main Content */
main {
    padding: 40px 20px;
}

.section {
    margin-bottom: 60px;
}

.section h2 {
    font-size: 2rem;
    margin-bottom: 30px;
    color: var(--text-primary);
    border-bottom: 3px solid var(--accent-color);
    padding-bottom: 10px;
}

/* About Section */
.about-content p {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 20px;
    color: var(--text-primary);
}

/* Experience Section */
.experience-item {
    background-color: var(--card-bg);
    border-radius: 10px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 4px 12px var(--shadow);
    transition: var(--transition);
    border-left: 4px solid var(--accent-color);
}

.experience-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 20px var(--shadow);
}

.experience-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
    flex-wrap: wrap;
    gap: 10px;
}

.experience-header h3 {
    font-size: 1.5rem;
    color: var(--accent-color);
    margin-bottom: 5px;
}

.company {
    font-size: 1.1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.duration {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 600;
    background-color: var(--bg-secondary);
    padding: 5px 15px;
    border-radius: 20px;
    white-space: nowrap;
}

.project-info {
    font-size: 0.95rem;
    margin-bottom: 8px;
    color: var(--text-primary);
}

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

.responsibilities {
    list-style: none;
    padding-left: 0;
    margin-top: 15px;
}

.responsibilities li {
    padding-left: 25px;
    margin-bottom: 10px;
    position: relative;
    color: var(--text-primary);
}

.responsibilities li:before {
    content: "▹";
    position: absolute;
    left: 0;
    color: var(--accent-color);
    font-weight: bold;
    font-size: 1.2rem;
}

.sub-project {
    margin-top: 25px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.sub-project:first-child {
    margin-top: 10px;
    padding-top: 10px;
    border-top: none;
}

/* Certificates Section */
.certificate-item {
    background-color: var(--card-bg);
    border-radius: 10px;
    padding: 30px;
    margin-bottom: 25px;
    box-shadow: 0 4px 12px var(--shadow);
    transition: var(--transition);
    border-left: 4px solid var(--accent-color);
}

.certificate-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 20px var(--shadow);
}

.certificate-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 15px;
    flex-wrap: wrap;
    gap: 10px;
}

.certificate-title-group h3 {
    font-size: 1.4rem;
    color: var(--accent-color);
    margin-bottom: 8px;
}

.certificate-org {
    font-size: 1.05rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.certificate-details {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 5px;
    font-style: italic;
}

.certificate-date {
    font-size: 0.95rem;
    color: var(--text-secondary);
    font-weight: 600;
    background-color: var(--bg-secondary);
    padding: 5px 15px;
    border-radius: 20px;
    white-space: nowrap;
}

.certificate-link {
    margin-top: 10px;
}

.certificate-link a {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 10px 20px;
    background-color: var(--accent-color);
    color: white;
    text-decoration: none;
    border-radius: 5px;
    transition: var(--transition);
    font-weight: 500;
}

.certificate-link a:hover {
    background-color: var(--accent-hover);
    transform: translateX(5px);
}

.link-icon {
    font-size: 1.2rem;
}

/* Contact Section */
.contact-content {
    background-color: var(--card-bg);
    border-radius: 10px;
    padding: 40px;
    box-shadow: 0 4px 12px var(--shadow);
}

.contact-intro {
    margin-bottom: 30px;
    text-align: center;
}

.contact-intro p {
    font-size: 1.1rem;
    color: var(--text-secondary);
}

/* Contact Form */
.contact-form {
    margin-bottom: 40px;
}

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

[data-theme="dark"] .form-group input:focus,
[data-theme="dark"] .form-group textarea:focus {
    box-shadow: 0 0 0 3px rgba(77, 166, 255, 0.2);
}

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

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-secondary);
    opacity: 0.6;
}

.submit-btn {
    background-color: var(--accent-color);
    color: white;
    padding: 14px 40px;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    width: 100%;
    max-width: 300px;
    display: block;
    margin: 0 auto;
}

.submit-btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

.submit-btn:active {
    transform: translateY(0);
}

.submit-btn:disabled {
    background-color: var(--text-secondary);
    cursor: not-allowed;
    transform: none;
}

.form-status {
    margin-top: 20px;
    padding: 12px;
    border-radius: 8px;
    text-align: center;
    font-weight: 500;
    display: none;
}

.form-status.success {
    display: block;
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.form-status.error {
    display: block;
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

[data-theme="dark"] .form-status.success {
    background-color: #1e4620;
    color: #8fd19e;
    border-color: #2d5930;
}

[data-theme="dark"] .form-status.error {
    background-color: #4a1c1c;
    color: #f08080;
    border-color: #6b2929;
}

/* Social Links */
.social-links {
    margin-top: 40px;
    padding-top: 40px;
    border-top: 2px solid var(--border-color);
}

.social-links h3 {
    text-align: center;
    margin-bottom: 20px;
    color: var(--text-primary);
    font-size: 1.3rem;
}

.contact-links {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 20px;
    background-color: var(--bg-secondary);
    border-radius: 8px;
    text-decoration: none;
    color: var(--text-primary);
    transition: var(--transition);
    border: 2px solid transparent;
}

.contact-item:hover {
    border-color: var(--accent-color);
    transform: translateX(10px);
    background-color: var(--card-bg);
}

.contact-icon {
    font-size: 1.8rem;
}

.contact-item span:last-child {
    font-size: 1.1rem;
    font-weight: 500;
}

/* Footer */
footer {
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
    text-align: center;
    padding: 30px 20px;
    margin-top: 60px;
    border-top: 1px solid var(--border-color);
}

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

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

    .nav-links {
        flex-direction: column;
        align-items: center;
    }

    .nav-links a {
        padding: 15px 20px;
        width: 100%;
        text-align: center;
    }

    .section h2 {
        font-size: 1.6rem;
    }

    .experience-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .duration {
        margin-top: 5px;
    }

    .experience-item {
        padding: 20px;
    }

    .contact-content {
        padding: 25px;
    }

    .theme-toggle {
        top: 15px;
        right: 15px;
    }

    #themeToggle {
        width: 45px;
        height: 45px;
        font-size: 1.3rem;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.6rem;
    }

    header .subtitle {
        font-size: 1rem;
    }

    .section h2 {
        font-size: 1.4rem;
    }

    .experience-header h3 {
        font-size: 1.2rem;
    }

    .about-content p {
        font-size: 1rem;
    }

    .contact-item {
        padding: 15px;
    }

    .contact-icon {
        font-size: 1.5rem;
    }

    .contact-item span:last-child {
        font-size: 1rem;
    }

    .certificate-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .certificate-date {
        margin-top: 5px;
    }

    .certificate-link a {
        width: 100%;
        justify-content: center;
    }
}

/* Print Styles */
@media print {
    .theme-toggle,
    nav {
        display: none;
    }

    body {
        background-color: white;
        color: black;
    }

    .experience-item {
        page-break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ccc;
    }
}