:root {
    --background: 240 5.9% 97.5%;
    --foreground: 240 10% 3.9%;
    --card: 0 0% 100%;
    --card-foreground: 240 10% 3.9%;
    --popover: 0 0% 100%;
    --popover-foreground: 240 10% 3.9%;
    --primary: 240 5.9% 10%;
    --primary-foreground: 0 0% 98%;
    --secondary: 240 4.8% 95.9%;
    --secondary-foreground: 240 5.9% 10%;
    --muted: 240 4.8% 95.9%;
    --muted-foreground: 240 3.8% 46.1%;
    --accent: 240 4.8% 95.9%;
    --accent-foreground: 240 5.9% 10%;
    --destructive: 0 84.2% 60.2%;
    --destructive-foreground: 0 0% 98%;
    --border: 240 5.9% 90%;
    --input: 240 5.9% 90%;
    --ring: 240 5.9% 10%;
    --radius: 0.5rem;
    --shadow-color: 0 0% 0%;
    --overlay-color: var(--background);
}
.dark-mode {
    --background: 240 10% 3.9%;
    --foreground: 0 0% 98%;
    --card: 240 10% 3.9%;
    --card-foreground: 0 0% 98%;
    --popover: 0 0% 100%;
    --popover-foreground: 240 10% 3.9%;
    --primary: 0 0% 98%;
    --primary-foreground: 240 5.9% 10%;
    --secondary: 240 3.7% 15.9%;
    --secondary-foreground: 0 0% 98%;
    --muted: 240 3.7% 15.9%;
    --muted-foreground: 240 5% 64.9%;
    --accent: 240 3.7% 15.9%;
    --accent-foreground: 0 0% 98%;
    --destructive: 0 62.8% 30.6%;
    --destructive-foreground: 0 0% 98%;
    --border: 240 3.7% 15.9%;
    --input: 240 3.7% 15.9%;
    --ring: 0 0% 98%;
    --shadow-color: 0 0% 100%;
    --overlay-color: var(--background);
}
body {
    font-family: 'Inter', sans-serif;
    line-height: 1.5;
    margin: 0;
    padding: 0;
    background-color: hsl(var(--background));
    color: hsl(var(--foreground));
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}
.header {
    background-color: hsl(var(--card));
    color: hsl(var(--card-foreground));
    padding: 2rem 0;
    text-align: center;
    box-shadow: 0 2px 4px hsl(var(--shadow-color) / 0.04);
    position: relative;
    border-bottom: 1px solid hsl(var(--border));
}
.header h1 {
    margin: 0;
    font-size: 3em;
    letter-spacing: -0.025em;
    font-weight: 700;
}
.header p {
    font-size: 1.1em;
    margin-top: 0.5rem;
    opacity: 0.7;
}
.theme-toggle-button {
    background-color: transparent;
    color: hsl(var(--foreground));
    border: 1px solid hsl(var(--border));
    padding: 0.5rem;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2em;
    position: fixed;
    top: 1.5rem;
    right: 1.5rem;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}
.theme-toggle-button:hover {
    background-color: hsl(var(--muted));
    border-color: hsl(var(--primary));
}
.theme-toggle-button .light-icon {
    display: block;
}
.theme-toggle-button .dark-icon {
    display: none;
}
.dark-mode .theme-toggle-button .light-icon {
    display: none;
}
.dark-mode .theme-toggle-button .dark-icon {
    display: block;
}
.theme-transition-overlay {
    position: fixed;
    width: 100px;
    height: 100px;
    background-color: hsl(var(--overlay-color));
    border-radius: 50%;
    transform: scale(0);
    z-index: 999;
    pointer-events: none;
    opacity: 0;
    visibility: hidden;
}
.avatar {
    width: 120px;
    height: 120px;
    border-radius: var(--radius);
    object-fit: cover;
    border: 2px solid hsl(var(--primary));
    margin-bottom: 1rem;
    box-shadow: 0 4px 10px hsl(var(--shadow-color) / 0.1);
}
.main-content {
    flex: 1;
    padding: 3rem 2rem;
    max-width: 960px;
    margin: 2.5rem auto;
    background-color: hsl(var(--card));
    border-radius: var(--radius);
    box-shadow: 0 5px 15px hsl(var(--shadow-color) / 0.08);
    border: 1px solid hsl(var(--border));
}
.section {
    margin-bottom: 3rem;
    padding-bottom: 2.5rem;
    border-bottom: 1px solid hsl(var(--muted));
}
.section:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}
.section h2 {
    color: hsl(var(--foreground));
    font-size: 2.5em;
    margin-bottom: 1.8rem;
    text-align: center;
    position: relative;
    font-weight: 600;
}
.section h2::after {
    content: '';
    width: 80px;
    height: 4px;
    background-color: hsl(var(--primary));
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    bottom: -15px;
    border-radius: 2px;
}
.section p {
    text-align: left;
    font-size: 1.05em;
    color: hsl(var(--muted-foreground));
    max-width: 800px;
    margin: 0 auto;
}
.tech-stack-category {
    margin-bottom: 2rem;
    padding: 1.5rem;
    border-radius: var(--radius);
    background-color: hsl(var(--secondary));
    box-shadow: 0 1px 3px hsl(var(--shadow-color) / 0.02);
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid hsl(var(--border));
}
.tech-stack-category:hover {
    box-shadow: 0 3px 8px hsl(var(--shadow-color) / 0.05);
    background-color: hsl(var(--secondary) / 0.8);
}
.tech-stack-category h3 {
    color: hsl(var(--foreground));
    font-size: 1.6em;
    margin-bottom: 1rem;
    border-left: 4px solid hsl(var(--primary));
    padding-left: 15px;
    font-weight: 600;
}
.tech-stack-category ul {
    list-style: none;
    padding: 0;
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}
.tech-stack-category li {
    background-color: hsl(var(--muted));
    color: hsl(var(--muted-foreground));
    padding: 10px 18px;
    border-radius: var(--radius);
    font-size: 0.9em;
    transition: background-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: 0 1px 2px hsl(var(--shadow-color) / 0.02);
    border: 1px solid hsl(var(--border));
    font-weight: 500;
    display: flex;
    align-items: center;
}
.tech-icon {
    width: 20px;
    height: 20px;
    margin-right: 8px;
    object-fit: contain;
}
.tech-stack-category li:hover {
    background-color: hsl(var(--muted) / 0.8);
    box-shadow: 0 2px 6px hsl(var(--shadow-color) / 0.15);
}
.footer {
    background-color: hsl(var(--card));
    color: hsl(var(--card-foreground));
    text-align: center;
    padding: 1.8rem 0;
    margin-top: 3rem;
    font-size: 0.9em;
    border-top: 1px solid hsl(var(--border));
}
.section ul {
    list-style: none;
    padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}
.section li {
    background-color: hsl(var(--card));
    color: hsl(var(--card-foreground));
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: 0 2px 5px hsl(var(--shadow-color) / 0.03);
    border: 1px solid hsl(var(--border));
    transition: transform 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
    font-size: 1.05em;
    font-weight: 500;
}
.section li:hover {
    background-color: hsl(var(--card) / 0.8);
    border-color: hsl(var(--primary));
    box-shadow: 0 4px 12px hsl(var(--shadow-color) / 0.2);
}
@media (max-width: 768px) {
    .header {
        padding: 1.5rem 0;
    }
    .header h1 {
        font-size: 2.2em;
    }
    .header p {
        font-size: 1em;
    }
    .theme-toggle-button {
        top: 1rem;
        right: 1rem;
        width: 36px;
        height: 36px;
        font-size: 1em;
    }
    .avatar {
        width: 100px;
        height: 100px;
    }
    .main-content {
        padding: 2rem 1rem;
        margin: 1.5rem auto;
    }
    .section h2 {
        font-size: 2em;
        margin-bottom: 1.5rem;
    }
    .section h2::after {
        bottom: -10px;
    }
    .section p {
        font-size: 1em;
    }
    .tech-stack-category {
        padding: 1rem;
    }
    .tech-stack-category h3 {
        font-size: 1.4em;
    }
    .tech-stack-category ul {
        gap: 8px;
    }
    .tech-stack-category li {
        padding: 8px 15px;
        font-size: 0.85em;
    }
    .tech-icon {
        width: 18px;
        height: 18px;
        margin-right: 6px;
    }
    .section ul {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 15px;
    }
    .section li {
        padding: 1rem;
        font-size: 1em;
    }
}