/* Reset và Base Styles */
:root {
    /* Primary Colors */
    --primary-color: #667eea;
    --primary-dark: #5a6fd8;
    --primary-light: #7c8ef0;
    
    /* Secondary Colors */
    --secondary-color: #764ba2;
    --secondary-dark: #6a4190;
    --secondary-light: #8a5bb8;
    
    /* Background Colors - Sử dụng màu hero section làm chủ đạo */
    --bg-primary: #f5f7fa;
    --bg-secondary: #e8ecf1;
    --bg-tertiary: #dde4ed;
    --bg-dark: #2c3e50;
    --bg-hero: #c3cfe2;
    
    /* Text Colors */
    --text-primary: #333333;
    --text-secondary: #666666;
    --text-light: #999999;
    --text-white: #ffffff;
    
    /* Accent Colors */
    --accent-success: #4CAF50;
    --accent-error: #f44336;
    --accent-warning: #ff9800;
    --accent-info: #2196F3;
    
    /* Gradient Colors */
    --gradient-primary: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    --gradient-light: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    --gradient-dark: linear-gradient(135deg, var(--primary-dark) 0%, var(--secondary-dark) 100%);
    --gradient-bg: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-hero) 100%);
    
    /* Overlay Colors */
    --overlay-primary: rgba(102, 126, 234, 0.9);
    --overlay-secondary: rgba(118, 75, 162, 0.9);
    --overlay-dark: rgba(0, 0, 0, 0.8);
    --overlay-light: rgba(245, 247, 250, 0.95);
    
    /* Border Colors */
    --border-light: #e8ecf1;
    --border-medium: #dde4ed;
    --border-dark: #c3cfe2;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    overflow-x: hidden;
    background: var(--gradient-bg);
    min-height: 100vh;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

h1 { font-size: 3.5rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 2rem; }
h4 { font-size: 1.5rem; }

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 30px;
    text-decoration: none;
    border-radius: 50px;
    font-weight: 500;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 1rem;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px var(--overlay-primary);
}

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

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

.btn-secondary.coming-soon {
    background: var(--accent-warning);
    color: var(--text-white);
    border-color: var(--accent-warning);
    cursor: not-allowed;
    position: relative;
    overflow: hidden;
}

.btn-secondary.coming-soon::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.btn-secondary.coming-soon:hover::before {
    left: 100%;
}

.btn-secondary.coming-soon:hover {
    background: var(--accent-warning);
    color: var(--text-white);
    transform: none;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--text-white);
    backdrop-filter: blur(10px);
    z-index: 1000;
    padding: 1rem 0;
    transition: all 0.3s ease;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo a {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
}

.nav-menu {
    display: flex;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s ease;
}

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

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

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

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: var(--gradient-bg);
    padding-top: 80px;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    color: #333;
    margin-bottom: 1.5rem;
    line-height: 1.2;
    position: relative;
}



.highlight {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: #667eea;
    margin-bottom: 1rem;
    font-weight: 500;
}

.hero-description {
    font-size: 1.1rem;
    color: #666;
    margin-bottom: 2rem;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

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

.hero-avatar {
    width: 400px;
    height: 400px;
    border-radius: 50%;
    overflow: hidden;
    border: 8px solid white;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
}

.avatar-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* Section Headers */
.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title {
    font-size: 2.5rem;
    color: #333;
    margin-bottom: 1rem;
}

.section-subtitle {
    font-size: 1.2rem;
    color: #666;
    max-width: 600px;
    margin: 0 auto;
}

/* About Section */
.about {
    padding: 6rem 0;
    background: var(--gradient-bg);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.about-text h3 {
    color: #667eea;
    margin-bottom: 1.5rem;
}

.about-text p {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 1.5rem;
}

.skills {
    margin-top: 2rem;
}

.skill-item {
    margin-bottom: 1.5rem;
}

.skill-name {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #333;
}

.skill-bar {
    width: 100%;
    height: 8px;
    background: #f0f0f0;
    border-radius: 4px;
    overflow: hidden;
}

.skill-progress {
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 4px;
    transition: width 1s ease;
}

.about-image img {
    width: 100%;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
}

/* Experience Section */
/* Experience & Awards Section */
.experience-awards {
    padding: 6rem 0;
    background: var(--text-white);
}

.experience-awards-content {
    display: flex;
    flex-direction: column;
    gap: 4rem;
    margin-top: 3rem;
}

.experience-column,
.awards-column {
    display: flex;
    flex-direction: column;
}

.column-header {
    margin-bottom: 2rem;
    text-align: center;
}

.column-header h3 {
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.column-header i {
    color: var(--primary-color);
    font-size: 1.3rem;
}

/* Experience Grid */
.experience-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.experience-card {
    background: var(--text-white);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--border-light);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.experience-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-primary);
}

.experience-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.experience-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.experience-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-white);
    font-size: 1.5rem;
    box-shadow: 0 8px 25px rgba(102, 126, 234, 0.3);
    flex-shrink: 0;
}

.experience-period {
    background: var(--gradient-light);
    color: var(--primary-color);
    padding: 0.5rem 1rem;
    border-radius: 25px;
    font-weight: 600;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    border: 2px solid var(--primary-light);
}

.experience-content h3 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: 1.4rem;
    line-height: 1.3;
}

.experience-content h4 {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-size: 1.1rem;
    font-weight: 500;
}

.experience-content p {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.experience-skills {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.experience-skills li {
    background: var(--gradient-light);
    color: var(--primary-color);
    padding: 0.4rem 0.8rem;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 500;
    border: 1px solid var(--primary-light);
    transition: all 0.3s ease;
}

.experience-skills li:hover {
    background: var(--primary-color);
    color: var(--text-white);
    transform: translateY(-2px);
}

/* Awards Section */
.awards {
    padding: 6rem 0;
    background: var(--gradient-bg);
}

/* Awards Grid in merged layout */
.awards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.award-card {
    background: var(--text-white);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    position: relative;
}

.award-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.15);
}

.award-image {
    position: relative;
    height: 200px;
    overflow: hidden;
    background: var(--gradient-primary);
}

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

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

.award-placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    color: var(--text-white);
    font-size: 3rem;
}

.award-content {
    padding: 1.5rem;
}

.award-year {
    background: var(--primary-color);
    color: var(--text-white);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
    display: inline-block;
    margin-bottom: 1rem;
}

.award-content h3 {
    color: var(--text-primary);
    margin-bottom: 0.8rem;
    font-size: 1.2rem;
    line-height: 1.3;
}

.award-content p {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.award-organization {
    color: var(--primary-color);
    font-weight: 600;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Course Section */
.course {
    padding: 6rem 0;
    background: var(--gradient-bg);
}

.course-preview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.course-preview-card {
    background: var(--text-white);
    border-radius: 20px;
    padding: 2.5rem 2rem;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    text-align: center;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.course-preview-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.course-preview-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.15);
}

.course-preview-icon {
    width: 80px;
    height: 80px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    color: var(--text-white);
    font-size: 2rem;
    transition: all 0.3s ease;
}

.course-preview-card:hover .course-preview-icon {
    transform: scale(1.1) rotate(5deg);
}

.course-preview-card h3 {
    color: #333;
    margin-bottom: 1rem;
    font-size: 1.5rem;
    font-weight: 600;
}

.course-preview-card p {
    color: #666;
    line-height: 1.6;
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

.course-preview-stats {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    flex-wrap: wrap;
}

.course-preview-stats span {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: #667eea;
    font-weight: 500;
}

.course-preview-stats i {
    color: #f39c12;
}

.course-preview-cta {
    background: var(--text-white);
    border-radius: 20px;
    padding: 3rem;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.course-preview-cta-content h3 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    font-size: 2rem;
}

.course-preview-cta-content p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 2rem;
    font-size: 1.1rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.course-preview-cta-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.course-preview-cta-buttons .btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1rem;
    padding: 12px 25px;
}

/* Course Hero Section */
.course-hero {
    padding: 8rem 0 4rem;
    background: var(--gradient-primary);
    color: var(--text-white);
    text-align: center;
}

.course-hero-title {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--text-white);
}

.course-hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 2rem;
    color: var(--text-white);
    opacity: 0.9;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.course-hero .btn-secondary {
    color: white;
    border-color: white;
}

.course-hero .btn-secondary:hover {
    background: white;
    color: #667eea;
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.course-card {
    background: var(--text-white);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    position: relative;
}

.course-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.15);
}

.course-image {
    position: relative;
    overflow: hidden;
    height: 250px;
    background: var(--bg-secondary);
    border-radius: 20px 20px 0 0;
}

.course-image::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0.1;
    z-index: 1;
}

.course-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    transition: transform 0.3s ease;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    image-rendering: -webkit-optimize-contrast;
    image-rendering: crisp-edges;
}

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

.course-overlay {
    position: absolute;
    top: 15px;
    right: 15px;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2;
}

.course-level,
.course-duration {
    background: var(--overlay-primary);
    color: var(--text-white);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    backdrop-filter: blur(10px);
}

.course-duration {
    background: var(--overlay-secondary);
}

.course-content {
    padding: 1.5rem;
}

.course-title {
    font-size: 1.3rem;
    color: #333;
    margin-bottom: 1rem;
    line-height: 1.3;
}

.course-description {
    color: #666;
    line-height: 1.6;
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

.course-topics {
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: var(--bg-secondary);
    border-radius: 12px;
    border-left: 4px solid var(--primary-color);
}

.course-topics h4 {
    color: var(--text-primary);
    margin-bottom: 0.8rem;
    font-size: 1rem;
    font-weight: 600;
}

.course-topics ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.course-topics li {
    color: var(--text-secondary);
    padding: 0.3rem 0;
    font-size: 0.9rem;
    position: relative;
    padding-left: 1.2rem;
}

.course-topics li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
    font-size: 0.8rem;
}

.course-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
}

.course-students,
.course-rating {
    display: flex;
    align-items: center;
    gap: 5px;
    color: var(--primary-color);
}

.course-rating {
    color: var(--accent-warning);
}

.course-price {
    display: flex;
    justify-content: center;
    align-items: center;
    padding-top: 1rem;
    border-top: 1px solid var(--border-light);
}

.course-cta {
    text-align: center;
    background: var(--text-white);
    padding: 3rem;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.course-cta h3 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    font-size: 1.8rem;
}

.course-cta p {
    color: #666;
    margin-bottom: 2rem;
    font-size: 1.1rem;
}

/* Blog Section */
.blog {
    padding: 6rem 0;
    background: var(--gradient-bg);
}

.blog-link-container {
    text-align: center;
    padding: 2rem 0;
}

.blog-external-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.1rem;
    padding: 15px 35px;
    transition: all 0.3s ease;
}

.blog-external-link:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 35px rgba(102, 126, 234, 0.4);
}

.blog-external-link i {
    font-size: 1rem;
}

/* Contact Section */
.contact {
    padding: 6rem 0;
    background: var(--gradient-bg);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
}

.contact-item {
    display: flex;
    align-items: center;
    margin-bottom: 2rem;
}

.contact-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 1.5rem;
    color: white;
    font-size: 1.2rem;
}

.contact-details h4 {
    margin-bottom: 0.5rem;
    color: #333;
}

.contact-details p {
    color: #666;
    margin: 0;
}

.contact-form {
    background: var(--text-white);
    padding: 2rem;
    border-radius: 20px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    flex: 1;
}

.form-message {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 10px;
    text-align: center;
    font-weight: 500;
}

.form-message.success {
    background: var(--accent-success);
    color: var(--text-white);
    border: 1px solid var(--accent-success);
}

.form-message.error {
    background: var(--accent-error);
    color: var(--text-white);
    border: 1px solid var(--accent-error);
}

.btn-loading {
    display: none;
}

.btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #f0f0f0;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
    font-family: inherit;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #667eea;
}

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

/* Footer */
.footer {
    background: var(--bg-dark);
    color: var(--text-white);
    padding: 3rem 0 1rem;
    margin-top: 2rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer-logo h3 {
    color: #667eea;
    margin-bottom: 0.5rem;
}

.footer-logo p {
    color: #bdc3c7;
    margin: 0;
}

.footer-social {
    display: flex;
    gap: 1rem;
}

.social-link {
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-white);
    text-decoration: none;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.social-link::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s ease;
}

.social-link:hover::after {
    left: 100%;
}

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

.social-link {
    position: relative;
}

.social-link .tooltip {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--overlay-dark);
    color: var(--text-white);
    padding: 5px 10px;
    border-radius: 5px;
    font-size: 0.8rem;
    white-space: nowrap;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    margin-bottom: 5px;
    pointer-events: none;
}

.social-link .tooltip::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    border: 5px solid transparent;
    border-bottom-color: var(--overlay-dark);
}

.social-link:hover .tooltip {
    opacity: 1;
    visibility: visible;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border-dark);
    color: var(--text-light);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--text-white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 2rem 0;
    }

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

    .nav-toggle {
        display: flex;
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }

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

    .hero-avatar {
        width: 300px;
        height: 300px;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .contact-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .experience-awards-content {
        gap: 3rem;
    }

    .experience-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .awards-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .experience-card {
        padding: 1.5rem;
    }

    .experience-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .experience-icon {
        width: 50px;
        height: 50px;
        font-size: 1.2rem;
    }

    .experience-period {
        font-size: 0.8rem;
        padding: 0.4rem 0.8rem;
    }



    .award-card {
        margin-bottom: 1rem;
    }

    .portfolio-grid {
        grid-template-columns: 1fr;
    }

    .blog-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 250px;
        text-align: center;
    }

    .portfolio-filters {
        flex-direction: column;
        align-items: center;
    }

    .experience-awards-content {
        gap: 2rem;
    }

    .experience-grid {
        gap: 1rem;
    }

    .awards-grid {
        gap: 1rem;
    }

    .experience-card {
        padding: 1rem;
    }

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

    .experience-skills {
        gap: 0.3rem;
    }

    .experience-skills li {
        font-size: 0.75rem;
        padding: 0.3rem 0.6rem;
    }

    .column-header h3 {
        font-size: 1.3rem;
    }

    .filter-btn {
        width: 100%;
        max-width: 200px;
    }
}