/* Core CSS Custom Properties */
/* Default theme: Light Mode */
:root {
    --bg-primary: #f8fafc;
    --bg-secondary: #f1f5f9;
    --card-bg: rgba(255, 255, 255, 0.7);
    --card-border: rgba(15, 23, 42, 0.06);
    --card-border-hover: rgba(15, 23, 42, 0.12);
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    
    --color-edu-primary: #2563eb;
    --color-edu-secondary: #7c3aed;
    --color-pyq-primary: #ea580c;
    --color-pyq-secondary: #db2777;
    
    --edu-grad: linear-gradient(135deg, var(--color-edu-primary) 0%, var(--color-edu-secondary) 100%);
    --pyq-grad: linear-gradient(135deg, var(--color-pyq-primary) 0%, var(--color-pyq-secondary) 100%);
    
    --font-sans: 'Outfit', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    
    --transition-smooth: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    
    /* Theme-specific details */
    --orb-opacity: 0.07;
    --logo-text-grad: linear-gradient(135deg, #0f172a 40%, #475569 100%);
    --header-border: rgba(15, 23, 42, 0.05);
    --about-bg: rgba(15, 23, 42, 0.01);
    --about-border: rgba(15, 23, 42, 0.03);
    
    --icon-link-bg: rgba(15, 23, 42, 0.02);
    --icon-link-border: rgba(15, 23, 42, 0.06);
    --icon-link-hover-bg: rgba(15, 23, 42, 0.06);
    --icon-link-hover-border: rgba(15, 23, 42, 0.12);
    
    --tech-tag-bg: rgba(15, 23, 42, 0.03);
    --tech-tag-border: rgba(15, 23, 42, 0.05);
    --tech-tag-hover-bg: rgba(15, 23, 42, 0.06);
    --tech-tag-hover-border: rgba(15, 23, 42, 0.1);
    
    --footer-border: rgba(15, 23, 42, 0.05);
    --mouse-glow-opacity: 0.15;
}

/* Dark Mode Theme */
[data-theme="dark"] {
    --bg-primary: #05070c;
    --bg-secondary: #0a0d16;
    --card-bg: rgba(13, 19, 33, 0.45);
    --card-border: rgba(255, 255, 255, 0.05);
    --card-border-hover: rgba(255, 255, 255, 0.15);
    
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    
    --color-edu-primary: #3b82f6;
    --color-edu-secondary: #8b5cf6;
    --color-pyq-primary: #f97316;
    --color-pyq-secondary: #ec4899;
    
    --orb-opacity: 0.12;
    --logo-text-grad: linear-gradient(135deg, #f8fafc 40%, #94a3b8 100%);
    --header-border: rgba(255, 255, 255, 0.03);
    --about-bg: rgba(255, 255, 255, 0.01);
    --about-border: rgba(255, 255, 255, 0.02);
    
    --icon-link-bg: rgba(255, 255, 255, 0.02);
    --icon-link-border: rgba(255, 255, 255, 0.05);
    --icon-link-hover-bg: rgba(255, 255, 255, 0.08);
    --icon-link-hover-border: rgba(255, 255, 255, 0.15);
    
    --tech-tag-bg: rgba(255, 255, 255, 0.03);
    --tech-tag-border: rgba(255, 255, 255, 0.05);
    --tech-tag-hover-bg: rgba(255, 255, 255, 0.05);
    --tech-tag-hover-border: rgba(255, 255, 255, 0.08);
    
    --footer-border: rgba(255, 255, 255, 0.03);
    --mouse-glow-opacity: 0.06;
}

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

html, body {
    width: 100%;
    min-height: 100vh;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-sans);
    overflow-x: hidden;
    scroll-behavior: smooth;
    line-height: 1.6;
    transition: background-color 0.4s ease, color 0.4s ease;
}

/* Background Particle Canvas */
#particle-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -2;
    pointer-events: none;
}

/* Ambient Glowing Orbs */
.glowing-orb {
    position: fixed;
    width: 50vw;
    height: 50vw;
    border-radius: 50%;
    filter: blur(120px);
    opacity: var(--orb-opacity);
    z-index: -1;
    pointer-events: none;
    animation: orb-float 20s infinite alternate ease-in-out;
    transition: opacity 0.4s ease;
}

.orb-1 {
    top: -10%;
    left: -10%;
    background: radial-gradient(circle, var(--color-edu-primary) 0%, rgba(59, 130, 246, 0) 70%);
}

.orb-2 {
    bottom: -10%;
    right: -10%;
    background: radial-gradient(circle, var(--color-pyq-secondary) 0%, rgba(236, 72, 153, 0) 70%);
    animation-delay: -5s;
}

@keyframes orb-float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(8%, 5%) scale(1.1); }
}

/* Main Layout Wrapper */
.app-container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1.5rem 4rem 1.5rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header Styling */
.main-header {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--header-border);
    margin-bottom: 4rem;
    transition: border-bottom 0.4s ease;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    width: 32px;
    height: 32px;
    filter: drop-shadow(0 2px 8px rgba(59, 130, 246, 0.3));
}

.logo-text {
    font-size: 1.35rem;
    font-weight: 800;
    letter-spacing: 0.05em;
    background: var(--logo-text-grad);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    transition: var(--transition-smooth);
}

.status-indicator {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    background: rgba(16, 185, 129, 0.08);
    border: 1px solid rgba(16, 185, 129, 0.15);
    padding: 0.25rem 0.6rem;
    border-radius: 99px;
    font-size: 0.75rem;
    font-weight: 500;
    color: #10b981;
    letter-spacing: 0.02em;
    margin-left: 0.5rem;
}

.pulse-dot {
    width: 6px;
    height: 6px;
    background-color: #10b981;
    border-radius: 50%;
    box-shadow: 0 0 8px #10b981;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(0.9); opacity: 0.6; }
    50% { transform: scale(1.15); opacity: 1; box-shadow: 0 0 12px #10b981; }
    100% { transform: scale(0.9); opacity: 0.6; }
}

.header-links {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.icon-link {
    color: var(--text-secondary);
    transition: var(--transition-smooth);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--icon-link-bg);
    border: 1px solid var(--icon-link-border);
    cursor: pointer;
    outline: none;
}

.icon-link:hover {
    color: var(--text-primary);
    background: var(--icon-link-hover-bg);
    border-color: var(--icon-link-hover-border);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

/* Theme Icons Toggle Visibility */
.theme-icon-moon,
.theme-icon-sun {
    width: 20px;
    height: 20px;
    transition: var(--transition-smooth);
}

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

[data-theme="dark"] .theme-icon-sun {
    display: block !important;
}

:root:not([data-theme="dark"]) .theme-icon-moon {
    display: block;
}

:root:not([data-theme="dark"]) .theme-icon-sun {
    display: none !important;
}

/* Hero Section */
.hero-section {
    text-align: center;
    margin-bottom: 5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    line-height: 1.15;
    margin-bottom: 0.75rem;
}

.gradient-text {
    background: linear-gradient(135deg, #2563eb 0%, #7c3aed 50%, #db2777 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

[data-theme="dark"] .gradient-text {
    background: linear-gradient(135deg, #60a5fa 0%, #c084fc 50%, #f472b6 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 300;
    color: var(--text-secondary);
    letter-spacing: 0.15em;
    margin-bottom: 2rem;
    text-transform: uppercase;
}

.about-container {
    max-width: 680px;
    padding: 1.5rem 2rem;
    background: var(--about-bg);
    border: 1px solid var(--about-border);
    border-radius: 16px;
    backdrop-filter: blur(8px);
    transition: background-color 0.4s ease, border-color 0.4s ease;
}

.about-text {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    text-align: justify;
}

/* Projects Grid Layout */
.projects-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 6rem;
    flex-grow: 1;
}

/* Project Card Base */
.project-card {
    position: relative;
    border-radius: 24px;
    background-color: var(--card-bg);
    border: 1px solid var(--card-border);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    overflow: hidden;
    text-decoration: none;
    color: inherit;
    display: flex;
    flex-direction: column;
    transition: var(--transition-smooth);
    z-index: 1;
}

.project-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(800px circle at var(--mouse-x, 0) var(--mouse-y, 0), rgba(255, 255, 255, var(--mouse-glow-opacity)), transparent 40%);
    z-index: -1;
    opacity: 0;
    transition: opacity 0.5s ease;
    pointer-events: none;
}

/* Give a slightly darker hover light to light mode, bright highlight on hover */
:root:not([data-theme="dark"]) .project-card::before {
    background: radial-gradient(800px circle at var(--mouse-x, 0) var(--mouse-y, 0), rgba(99, 102, 241, var(--mouse-glow-opacity)), transparent 45%);
}

.project-card:hover::before {
    opacity: 1;
}

.project-card:hover {
    transform: translateY(-6px);
    border-color: var(--card-border-hover);
    box-shadow: 0 20px 40px rgba(15, 23, 42, 0.06);
}

[data-theme="dark"] .project-card:hover {
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.card-glow {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: 24px;
    opacity: 0;
    transition: opacity 0.5s ease;
    z-index: -2;
    pointer-events: none;
}

.edu-card .card-glow {
    background: radial-gradient(circle at top left, rgba(37, 99, 235, 0.08) 0%, transparent 60%);
}

[data-theme="dark"] .edu-card .card-glow {
    background: radial-gradient(circle at top left, rgba(59, 130, 246, 0.15) 0%, transparent 60%);
}

.pyq-card .card-glow {
    background: radial-gradient(circle at top left, rgba(219, 39, 119, 0.08) 0%, transparent 60%);
}

[data-theme="dark"] .pyq-card .card-glow {
    background: radial-gradient(circle at top left, rgba(236, 72, 153, 0.15) 0%, transparent 60%);
}

.project-card:hover .card-glow {
    opacity: 1;
}

.card-content {
    padding: 2.5rem;
    display: flex;
    flex-direction: column;
    height: 100%;
    z-index: 2;
}

/* Card Header */
.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.card-icon-wrapper {
    width: 54px;
    height: 54px;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--icon-link-bg);
    border: 1px solid var(--icon-link-border);
    transition: var(--transition-smooth);
}

.card-icon {
    width: 26px;
    height: 26px;
    color: var(--text-secondary);
    transition: var(--transition-smooth);
}

.edu-card:hover .card-icon-wrapper {
    background: rgba(37, 99, 235, 0.08);
    border-color: rgba(37, 99, 235, 0.3);
}

[data-theme="dark"] .edu-card:hover .card-icon-wrapper {
    background: rgba(59, 130, 246, 0.1);
    border-color: rgba(59, 130, 246, 0.3);
}

.edu-card:hover .card-icon {
    color: var(--color-edu-primary);
    transform: scale(1.05);
}

.pyq-card:hover .card-icon-wrapper {
    background: rgba(219, 39, 119, 0.08);
    border-color: rgba(219, 39, 119, 0.3);
}

[data-theme="dark"] .pyq-card:hover .card-icon-wrapper {
    background: rgba(236, 72, 153, 0.1);
    border-color: rgba(236, 72, 153, 0.3);
}

.pyq-card:hover .card-icon {
    color: var(--color-pyq-secondary);
    transform: scale(1.05);
}

.card-status-badge {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    background: var(--icon-link-bg);
    border: 1px solid var(--icon-link-border);
    padding: 0.25rem 0.6rem;
    border-radius: 8px;
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--text-secondary);
    letter-spacing: 0.05em;
    transition: var(--transition-smooth);
}

.badge-dot {
    width: 5px;
    height: 5px;
    background-color: var(--text-muted);
    border-radius: 50%;
}

.edu-card:hover .badge-dot {
    background-color: var(--color-edu-primary);
    box-shadow: 0 0 6px var(--color-edu-primary);
}

.pyq-card:hover .badge-dot {
    background-color: var(--color-pyq-secondary);
    box-shadow: 0 0 6px var(--color-pyq-secondary);
}

/* Card Body */
.card-title {
    font-size: 1.45rem;
    font-weight: 700;
    margin-bottom: 1rem;
    letter-spacing: -0.01em;
    color: var(--text-primary);
    transition: var(--transition-smooth);
}

.edu-card:hover .card-title {
    background: var(--edu-grad);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.pyq-card:hover .card-title {
    background: var(--pyq-grad);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.card-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.6;
    margin-bottom: 2rem;
    flex-grow: 1;
    font-weight: 400;
}

[data-theme="dark"] .card-description {
    font-weight: 300;
}

/* Tech Tags */
.tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 2.5rem;
}

.tech-tag {
    font-size: 0.72rem;
    font-weight: 500;
    color: var(--text-secondary);
    background: var(--tech-tag-bg);
    border: 1px solid var(--tech-tag-border);
    padding: 0.25rem 0.6rem;
    border-radius: 6px;
    transition: var(--transition-smooth);
}

.project-card:hover .tech-tag {
    background: var(--tech-tag-hover-bg);
    border-color: var(--tech-tag-hover-border);
    color: var(--text-primary);
}

/* Card Action Link styling */
.card-footer-action {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: auto;
    transition: var(--transition-smooth);
}

.arrow-icon {
    width: 16px;
    height: 16px;
    transition: var(--transition-smooth);
}

.edu-card:hover .card-footer-action {
    color: var(--color-edu-primary);
}

.pyq-card:hover .card-footer-action {
    color: var(--color-pyq-secondary);
}

.project-card:hover .arrow-icon {
    transform: translateX(4px);
}

/* Footer Styling */
.main-footer {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-top: 1px solid var(--footer-border);
    padding-top: 2rem;
    font-size: 0.8rem;
    color: var(--text-muted);
    transition: border-top 0.4s ease;
}

.footer-meta {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.footer-tech {
    background: var(--tech-tag-bg);
    border: 1px solid var(--tech-tag-border);
    padding: 0.25rem 0.6rem;
    border-radius: 4px;
    transition: var(--transition-smooth);
}

/* Media Queries (Responsive Design) */

/* Tablets and below */
@media (max-width: 900px) {
    .projects-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .hero-title {
        font-size: 2.75rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
        letter-spacing: 0.1em;
    }
}

/* Mobile Devices */
@media (max-width: 600px) {
    .app-container {
        padding: 1rem 1rem 3rem 1rem;
    }
    
    .main-header {
        margin-bottom: 2.5rem;
    }
    
    .hero-section {
        margin-bottom: 3.5rem;
    }
    
    .hero-title {
        font-size: 2.25rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
        margin-bottom: 1.5rem;
    }
    
    .about-container {
        padding: 1rem;
    }
    
    .about-text {
        font-size: 0.85rem;
    }
    
    .card-content {
        padding: 1.75rem;
    }
    
    .card-title {
        font-size: 1.25rem;
    }
    
    .card-description {
        font-size: 0.85rem;
        margin-bottom: 1.5rem;
    }
    
    .tech-tags {
        margin-bottom: 1.75rem;
    }
    
    .main-footer {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
}