/* 1. Global Setup & Variables (DARK MODE Palette) */
:root {
    --color-primary-bg: #0F172A;
    /* Rich Dark Slate - Main background */
    --color-secondary-bg: #1E293B;
    /* Slightly Lighter Dark Slate for Cards */
    --color-text-dark: #F8FAFC;
    /* Near White - Headings, bold text */
    --color-text-medium: #94A3B8;
    /* Light Gray - Body text, links */
    --color-accent-main: #3B82F6;
    /* Vibrant Blue - Primary Accent */
    --color-accent-light: #1E3A8A;
    /* Dark Blue for subtle highlights/hovers */
    --color-border: #334155;
    /* Dark Border/Separator */

    /* Shadows adjusted for dark background */
    --shadow-card: 0 4px 12px 0 rgba(0, 0, 0, 0.4), 0 1px 3px 0 rgba(0, 0, 0, 0.2);
    --shadow-card-hover: 0 15px 30px -5px rgba(59, 130, 246, 0.25), 0 4px 6px -2px rgba(0, 0, 0, 0.1);
}

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

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;700;800;900&display=swap');

/* Utility for SVG Icons */
.icon {
    width: 1.25rem;
    height: 1.25rem;
    fill: none;
    stroke: currentColor;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* 2. Keyframe Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.98);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.animate-hero-title {
    animation: fadeInUp 1s cubic-bezier(0.165, 0.84, 0.44, 1) 0.2s both;
}

.animate-hero-subtitle {
    animation: fadeInUp 1s cubic-bezier(0.165, 0.84, 0.44, 1) 0.4s both;
}

.animate-contact-links {
    animation: fadeInUp 1s cubic-bezier(0.165, 0.84, 0.44, 1) 0.6s both;
}

.content-card,
.skill-group-card,
.project-card,
.chart-container,
.learning-card {
    animation: scaleIn 0.8s cubic-bezier(0.165, 0.84, 0.44, 1) forwards;
    opacity: 0;
}

#about .content-card {
    animation-delay: 0.2s;
}

#skills .chart-container {
    animation-delay: 0.4s;
}

#learning .content-card {
    animation-delay: 0.6s;
}


/* 3. Navigation */
.main-nav {
    position: sticky;
    top: 0;
    z-index: 50;
    background-color: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(16px);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    border-bottom: 1px solid var(--color-border);
}

.nav-title {
    font-size: 1.5rem;
    font-weight: 900;
    color: var(--color-text-dark);
    letter-spacing: -0.05em;
}

.nav-link {
    color: var(--color-text-medium);
    font-weight: 500;
    transition: color 0.3s, transform 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    width: 0;
    height: 3px;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--color-accent-main);
    border-radius: 9999px;
    transition: width 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
}

.nav-link:hover {
    color: var(--color-accent-main);
    transform: translateY(-2px);
}

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

/* 4. Hero & Contact Links */
.hero-title {
    font-size: 3.5rem;
    font-weight: 900;
    color: var(--color-text-dark);
    letter-spacing: -0.05em;
    margin-bottom: 1rem;
    line-height: 1.1;
}

.hero-title span {
    color: #E2E8F0;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--color-accent-main);
    font-weight: 400;
    margin-bottom: 2.5rem;
}

.contact-link {
    color: var(--color-text-medium);
    transition: color 0.3s, transform 0.3s, opacity 0.3s;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
}

.contact-link:hover {
    color: var(--color-text-dark);
    background-color: var(--color-accent-light);
    transform: translateY(-3px) scale(1.05);
}

@media (min-width: 768px) {
    .hero-title {
        font-size: 5.5rem;
    }

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

/* 5. Section Styling */
.section {
    margin-bottom: 8rem;
    scroll-margin-top: 6rem;
}

.section-heading {
    font-size: 2.8rem;
    font-weight: 900;
    color: var(--color-text-dark);
    margin-bottom: 3rem;
    text-align: center;
    position: relative;
}

.section-heading::after {
    content: '';
    display: block;
    width: 80px;
    height: 5px;
    background: linear-gradient(90deg, #3B82F6 0%, #1D4ED8 100%);
    margin: 0.75rem auto 0;
    border-radius: 9999px;
    box-shadow: 0 2px 4px rgba(59, 130, 246, 0.4);
}

/* Combined Card Styling (including the new learning-card) */
.content-card,
.skill-group-card,
.project-card,
.chart-container,
.learning-card {
    background-color: var(--color-secondary-bg);
    border-radius: 1.25rem;
    box-shadow: var(--shadow-card);
    border: 1px solid var(--color-border);
    transition: box-shadow 0.5s cubic-bezier(0.25, 0.8, 0.25, 1),
        transform 0.5s cubic-bezier(0.25, 0.8, 0.25, 1),
        border-color 0.5s;
    transform-style: preserve-3d;
    padding: 2.5rem;
}

/* Mobile padding adjustment */
@media (max-width: 640px) {

    .content-card,
    .skill-group-card,
    .project-card,
    .chart-container,
    .learning-card {
        padding: 1.5rem;
    }
}

.content-card:hover,
.skill-group-card:hover,
.project-card:hover,
.learning-card:hover {
    box-shadow: var(--shadow-card-hover);
    transform: translateY(-8px) scale(1.01) perspective(800px) rotateX(1deg);
    border-color: var(--color-accent-main);
}

/* Learning Section Specific */
.learning-title {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--color-text-dark);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
}

.learning-title svg {
    color: var(--color-accent-main);
    margin-right: 0.75rem;
}


/* 6. Skills Chart & Tags */
.chart-container {
    height: 400px;
}

.skill-group-title {
    font-weight: 800;
    font-size: 1.375rem;
    color: var(--color-text-dark);
    margin-bottom: 1rem;
    border-bottom: 3px solid var(--color-accent-light);
    padding-bottom: 0.5rem;
}

.skill-tag {
    font-size: 0.875rem;
    font-weight: 600;
    padding: 0.4rem 1rem;
    border-radius: 9999px;
    background-color: #334155;
    color: #E2E8F0;
    transition: background-color 0.3s, transform 0.2s;
}

.skill-tag:hover {
    background-color: #475569;
    transform: scale(1.05);
}

.skill-tag.highlight {
    background-color: #1E3A8A;
    color: #DBEAFE;
    border: 1px solid var(--color-accent-main);
}

/* 7. Projects */
.project-filters {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    flex-wrap: wrap;
    margin-bottom: 3rem;
}

.filter-btn {
    padding: 0.7rem 1.8rem;
    border-radius: 9999px;
    font-weight: 700;
    transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
    border: 1px solid transparent;
    cursor: pointer;
}

.filter-btn-default {
    background-color: var(--color-secondary-bg);
    color: var(--color-text-medium);
    border-color: var(--color-border);
}

.filter-btn-default:hover {
    background-color: #2F415A;
    color: var(--color-accent-main);
    border-color: var(--color-accent-main);
    transform: translateY(-2px);
}

.filter-btn-active {
    background: linear-gradient(45deg, #3B82F6, #1D4ED8);
    color: var(--color-secondary-bg);
    box-shadow: 0 6px 15px -4px rgba(59, 130, 246, 0.6);
    border-color: transparent;
}

.project-title {
    font-size: 1.6rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    color: var(--color-text-dark);
}

.project-title span {
    color: var(--color-accent-main);
    transition: color 0.3s;
}

.project-card:hover .project-title span {
    color: #F97316;
}

/* Custom JS Transition CSS for details */
.project-card-details {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.7s cubic-bezier(0.42, 0, 0.58, 1), padding-top 0.7s;
    padding-top: 0;
}

.project-card.open .project-card-details {
    max-height: 800px;
    transition: max-height 0.7s cubic-bezier(0.42, 0, 0.58, 1), padding-top 0.7s;
    padding-top: 1.5rem;
}

.card-expand-link {
    font-size: 0.95rem;
    color: var(--color-accent-main);
    margin-top: 1.5rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    transition: color 0.3s;
    cursor: pointer; /* Ensure it looks clickable */
}

.card-expand-link:hover {
    color: #38A169;
}

.indicator-icon {
    transition: transform 0.4s;
}

.project-card.open .indicator-icon {
    transform: rotate(180deg);
}

.project-link-btn {
    display: inline-flex;
    align-items: center;
    padding: 0.6rem 1.2rem;
    margin-top: 1.5rem;
    background: linear-gradient(90deg, #3B82F6, #1D4ED8);
    color: var(--color-secondary-bg);
    font-weight: 600;
    border-radius: 0.5rem;
    transition: background 0.3s, transform 0.3s, box-shadow 0.3s;
    box-shadow: 0 4px 8px rgba(59, 130, 246, 0.4);
    text-decoration: none;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.project-link-btn:hover {
    background: linear-gradient(90deg, #1D4ED8, #3B82F6);
    transform: translateY(-2px) scale(1.02);
    box-shadow: 0 6px 12px rgba(59, 130, 246, 0.6);
}


/* 8. Education */
.education-title {
    font-size: 1.8rem;
    font-weight: 900;
    color: var(--color-accent-main);
}

.education-subtitle {
    font-size: 1.4rem;
    color: var(--color-text-dark);
    font-weight: 700;
    margin-top: 0.5rem;
    margin-bottom: 0.25rem;
}

.certification-list li {
    padding: 1rem 0;
    border-bottom: 1px solid var(--color-border);
}

.certification-list li:last-child {
    border-bottom: none;
}

/* 9. Footer */
.site-footer {
    background-color: #111827;
    margin-top: 7rem;
    box-shadow: inset 0 4px 10px rgba(0, 0, 0, 0.3);
}