/* ========================================
   CSS VARIABLES & CUSTOM PROPERTIES
   ======================================== */
:root {
    /* Light Mode Colours */
    --bg-primary: #FFFFFF;
    --bg-secondary: #F8F5EC;
    --bg-tertiary: rgba(102, 125, 166, 0.1);
    
    --text-primary: #333333;
    --text-secondary: #666666;
    --text-inverse: #FFFFFF;
    
    --accent-primary: #233775;
    --accent-secondary: #45649C;
    --accent-tertiary: #667DA6;
    --accent-light: #0F2C68;
    
    
    /* Effects */
    --shadow: rgba(0, 0, 0, 0.08);
    --transition: all 0.3s ease;
    
    /* Spacing Scale */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-2xl: 5rem;
}

/* Dark Mode */
[data-theme="dark"] {
    /* Dark Mode Colours */
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-tertiary: rgba(102, 125, 166, 0.2);
    
    --text-primary: #e0e0e0;
    --text-secondary: #b0b0b0;
    --text-inverse: #1a1a1a;
    
    --accent-primary: #7FA6D6;
    --accent-secondary: #5B7FA6;
    --accent-tertiary: #8899AA;
    --accent-light: #A0B8D6;
    
    /* Effects for dark mode */
    --shadow: rgba(0, 0, 0, 0.3);
}

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

/* ========================================
   ACCESSIBILITY
   ======================================== */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--accent-primary);
    color: var(--text-inverse);
    padding: 8px;
    text-decoration: none;
    z-index: 100;
}

.skip-link:focus {
    top: 0;
}

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-secondary);
}

/* Focus Styles for Accessibility */
:focus {
    outline: 2px solid var(--denim-blue);
    outline-offset: 2px;
}

:focus:not(:focus-visible) {
    outline: none;
}

:focus-visible {
    outline: 2px solid var(--denim-blue);
    outline-offset: 2px;
}

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

/* ========================================
   NAVIGATION
   ======================================== */
.navbar {
    background-color: var(--bg-primary);
    box-shadow: 0 2px 4px var(--shadow);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-primary);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

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

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

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* Dark Mode Toggle */
.theme-toggle {
    background: none;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    padding: 0.75rem;
    border-radius: 5px;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 44px;
    min-height: 44px;
    touch-action: manipulation;
}

.theme-toggle:hover {
    background-color: var(--bg-secondary);
}

.sun-icon,
.moon-icon {
    display: block;
}

[data-theme="dark"] .sun-icon {
    display: none;
}

[data-theme="light"] .moon-icon,
:root:not([data-theme]) .moon-icon {
    display: none;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    background: none;
    border: none;
    padding: 5px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background-color: var(--accent-primary);
    margin: 3px 0;
    transition: var(--transition);
}

/* ========================================
   HERO SECTION
   ======================================== */
.hero {
    padding: 120px 0 80px;
    background-color: var(--bg-primary);
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
}

.profile-img {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    margin-bottom: 2rem;
    box-shadow: 0 4px 6px var(--shadow);
    transition: var(--transition);
}

.profile-img:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px var(--shadow);
}

.hero-title {
    font-size: 3rem;
    color: var(--accent-primary);
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.btn {
    padding: 14px 32px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: 600;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px; /* Touch-friendly size */
    min-width: 120px;
    line-height: 1.5;
    touch-action: manipulation; /* Improve touch responsiveness */
}

.btn-primary {
    background-color: var(--accent-secondary);
    color: var(--text-inverse);
}

.btn-primary:hover {
    background-color: var(--accent-primary);
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    background-color: var(--accent-secondary);
    color: var(--text-inverse);
}

/* ========================================
   ABOUT SECTION
   ======================================== */
.about {
    padding: 80px 0;
    background-color: var(--bg-secondary);
}

.section-title {
    font-size: 2.5rem;
    color: var(--accent-primary);
    text-align: center;
    margin-bottom: 3rem;
}

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

.about-text p {
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.values {
    background-color: var(--bg-primary);
    padding: 2rem;
    border-radius: 10px;
    margin-top: 2rem;
    box-shadow: 0 2px 4px var(--shadow);
}

.values h3 {
    color: var(--accent-primary);
    margin-bottom: 1rem;
}

.values ul {
    list-style: none;
}

.values li {
    padding: 0.5rem 0;
    color: var(--text-primary);
}

.values strong {
    color: var(--accent-secondary);
}

/* ========================================
   EXPERIENCE SECTION
   ======================================== */
.experience {
    padding: 80px 0;
    background-color: var(--bg-primary);
}

.timeline {
    max-width: 900px;
    margin: 0 auto;
    position: relative;
    padding: 2rem 0;
}

/* Central timeline line */
.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 3px;
    height: 100%;
    background: linear-gradient(to bottom, var(--accent-tertiary), var(--accent-secondary));
    opacity: 0.3;
}

.timeline-item {
    position: relative;
    margin-bottom: 4rem;
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}

/* Alternating layout */
.timeline-item:nth-child(even) {
    flex-direction: row-reverse;
}

/* Timeline dots */
.timeline-item::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 24px;
    height: 24px;
    background-color: var(--accent-secondary);
    border-radius: 50%;
    border: 4px solid var(--bg-primary);
    box-shadow: 0 0 0 3px var(--accent-tertiary);
    z-index: 10;
    transition: var(--transition);
}

.timeline-item:hover::before {
    transform: translateX(-50%) scale(1.2);
    background-color: var(--accent-primary);
}

/* Date styling */
.timeline-date {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    top: -30px;
    font-weight: 600;
    color: var(--accent-primary);
    font-size: 0.9rem;
    background-color: var(--bg-primary);
    padding: 0 1rem;
    white-space: nowrap;
}

/* Content boxes */
.timeline-content {
    width: 45%;
    background-color: var(--bg-secondary);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px var(--shadow);
    transition: var(--transition);
    border: 1px solid rgba(102, 125, 166, 0.1);
}

.timeline-item:nth-child(odd) .timeline-content {
    margin-right: auto;
}

.timeline-item:nth-child(even) .timeline-content {
    margin-left: auto;
}

.timeline-content:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 16px var(--shadow);
    border-color: var(--accent-tertiary);
}

.timeline-content h3 {
    color: var(--accent-primary);
    font-size: 1.4rem;
    margin-bottom: 0.3rem;
}

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

.timeline-content p {
    color: var(--text-primary);
    line-height: 1.7;
    margin-bottom: 0;
}

/* Animation classes */
.timeline-item[data-aos="fade-up"] {
    opacity: 0;
    transform: translateY(30px);
}

.timeline-item.aos-animate {
    opacity: 1;
    transform: translateY(0);
    transition: all 0.6s ease-out;
}

/* LinkedIn CTA */
.linkedin-cta {
    text-align: center;
    margin-top: 3rem;
    padding: 2rem;
    background-color: var(--bg-secondary);
    border-radius: 10px;
}

.linkedin-cta p {
    font-size: 1.1rem;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
}

.linkedin-cta .btn {
    margin: 0.5rem;
}


/* Projects Section */
.projects {
    padding: 80px 0;
    background-color: var(--bg-secondary);
}

.projects-intro {
    text-align: center;
    font-size: 1.2rem;
    color: var(--text-primary);
    max-width: 700px;
    margin: 0 auto 3rem;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.project-card {
    background-color: var(--bg-primary);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 2px 4px var(--shadow);
    transition: var(--transition);
    border-top: 4px solid var(--accent-secondary);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px var(--shadow);
}

.project-card h3 {
    color: var(--accent-primary);
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.project-type {
    display: inline-block;
    color: var(--accent-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 1rem;
    font-weight: 500;
}

.project-card p {
    color: var(--text-primary);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.project-stats {
    display: flex;
    gap: 1.5rem;
    margin-top: 1rem;
}

.project-stats span {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

.project-link {
    margin-top: 1rem;
}

.project-link a {
    color: var(--accent-secondary);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.project-link a:hover {
    color: var(--accent-primary);
}


/* Contact Section */
.contact {
    padding: 80px 0;
    background-color: var(--bg-primary);
}

.contact-content {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.contact-content p {
    font-size: 1.1rem;
    color: var(--text-primary);
    margin-bottom: 2rem;
}

.contact-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
}

.contact-item {
    background-color: var(--soft-ivory);
    padding: 2rem;
    border-radius: 10px;
    border: 1px solid rgba(102, 125, 166, 0.3);
}

.contact-item h3 {
    color: var(--deep-navy);
    margin-bottom: 1rem;
}

.contact-item p {
    color: var(--text-dark);
    font-size: 1rem;
}

/* Footer */
.footer {
    background-color: var(--accent-primary);
    color: var(--text-inverse);
    text-align: center;
    padding: 2rem 0;
}

.footer .disclaimer {
    font-size: 0.85rem;
    opacity: 0.8;
    margin-top: 0.5rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }
    
    .theme-toggle {
        order: -1; /* Put theme toggle before hamburger */
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--bg-primary);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px var(--shadow);
        padding: 2rem 0;
    }

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

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

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .hero-cta {
        flex-direction: column;
        align-items: center;
        gap: 0;
    }

    .hero-cta .btn {
        display: block;
        width: 100%;
        margin: 0.75rem 0;
    }

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

    /* Timeline mobile styles */
    .timeline::before {
        left: 15px;
        transform: none;
    }

    .timeline-item {
        flex-direction: column !important;
        padding-left: 50px;
        margin-bottom: 3rem;
        position: relative;
    }

    .timeline-item::before {
        left: 15px;
        transform: none;
        width: 16px;
        height: 16px;
        top: 2px;
        border: 3px solid var(--bg-primary);
    }

    .timeline-date {
        position: relative;
        left: 0;
        transform: none;
        top: 0;
        margin-bottom: 0.5rem;
        margin-left: 15px;
        padding: 0;
        font-size: 0.85rem;
        font-weight: 600;
        color: var(--accent-primary);
        background: none;
    }

    .timeline-content {
        width: 100%;
        margin: 0 !important;
    }

    .timeline-item:hover::before {
        transform: scale(1.2);
    }

    /* LinkedIn CTA mobile styles */
    .linkedin-cta {
        padding: 1.5rem;
    }

    .linkedin-cta p {
        font-size: 1rem;
    }

    .linkedin-cta .btn {
        display: block;
        width: 100%;
        margin: 0.75rem 0;
    }

    /* Contact CTA mobile styles */
    .contact-cta {
        flex-direction: column;
        gap: 0;
    }

    .contact-cta .btn {
        display: block;
        width: 100%;
        margin: 0.75rem 0;
    }

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


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

}

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

    .timeline-item {
        padding-left: 30px;
    }

    .timeline-item::before {
        width: 15px;
        height: 15px;
    }

    .timeline-item::after {
        left: 6px;
    }
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Active Navigation State */
.nav-link.active {
    color: var(--accent-secondary);
    font-weight: 600;
    position: relative;
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--accent-secondary);
}

/* Reduced Motion Support */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}