:root {
    /* --- Dark Theme --- */
    --bg-color: #0f172a;
    --header-bg: #1e293b;
    --text-color: #e2e8f0;
    --muted-text: #94a3b8;
    --accent-color: #38bdf8;
    --card-bg: #1e293b;
    --button-bg: #38bdf8;
    --button-hover: #0ea5e9;
}

/* --- Light Theme --- */
[data-theme="light"] {
    --bg-color: #f8fafc;
    --header-bg: #e2e8f0;
    --text-color: #0f172a;
    --muted-text: #334155;
    --accent-color: #0ea5e9;
    --card-bg: #f1f5f9;
    --button-bg: #0ea5e9;
    --button-hover: #0284c7;
}

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

body {
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.4s ease, color 0.4s ease;
}

header {
    background-color: var(--header-bg);
    padding: 1.5rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    transition: background-color 0.4s ease;
}

header h1 {
    color: var(--accent-color);
    font-size: 1.8rem;
}

nav a {
    color: var(--muted-text);
    text-decoration: none;
    margin: 0 1rem;
    font-weight: 500;
    transition: color 0.3s ease;
}

nav a:hover {
    color: var(--accent-color);
}

/* --- Theme Toggle Switch --- */
.theme-toggle {
    display: flex;
    align-items: center;
}

.theme-toggle input {
    display: none;
}

.switch {
    position: relative;
    width: 50px;
    height: 26px;
    background-color: var(--muted-text);
    border-radius: 25px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.switch::before {
    content: "";
    position: absolute;
    top: 3px;
    left: 3px;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background-color: var(--bg-color);
    transition: transform 0.3s ease, background-color 0.3s ease;
}

/* When switch is active */
.theme-toggle input:checked + .switch {
    background-color: var(--accent-color);
}

.theme-toggle input:checked + .switch::before {
    transform: translateX(24px);
}

/* --- Hero Section --- */
.hero {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    height: 80vh;
    background: linear-gradient(135deg, var(--header-bg), var(--bg-color));
    padding: 2rem;
    transition: background 0.4s ease;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--accent-color);
}

.hero p {
    max-width: 600px;
    color: var(--muted-text);
    font-size: 1.1rem;
}

.hero button {
    margin-top: 2rem;
    padding: 0.8rem 2rem;
    border: none;
    border-radius: 5px;
    background-color: var(--button-bg);
    color: var(--bg-color);
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.hero button:hover {
    background-color: var(--button-hover);
}

/* --- Section Styles --- */
section {
    padding: 4rem 2rem;
    max-width: 1000px;
    margin: auto;
    transition: color 0.4s ease, background-color 0.4s ease;
}

section h2 {
    text-align: center;
    color: var(--accent-color);
    margin-bottom: 1.5rem;
    font-size: 2rem;
}

/* --- About --- */
#about p {
    text-align: center;
    color: var(--muted-text);
    max-width: 700px;
    margin: auto;
    font-size: 1.05rem;
}

/* --- Skills --- */
#skills ul {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
    margin-top: 1rem;
}

#skills li {
    background-color: var(--card-bg);
    padding: 0.8rem 1.5rem;
    border-radius: 8px;
    color: var(--accent-color);
    font-weight: 600;
    transition: transform 0.3s ease, background-color 0.3s ease, color 0.3s ease;
}

#skills li:hover {
    background-color: var(--button-bg);
    color: var(--bg-color);
    transform: translateY(-4px);
}

/* --- Projects --- */
.projects-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.project-card {
    background-color: var(--card-bg);
    border-radius: 8px;
    padding: 1.5rem;
    transition: transform 0.3s ease, background-color 0.3s ease, color 0.3s ease;
}

.project-card:hover {
    transform: translateY(-5px);
    background-color: var(--button-bg);
    color: var(--bg-color);
}

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

.project-card p {
    color: var(--muted-text);
}

/* --- Footer --- */
footer {
    background-color: var(--header-bg);
    text-align: center;
    padding: 1rem;
    font-size: 0.9rem;
    color: var(--muted-text);
    transition: background-color 0.4s ease;
}

/* --- Responsive --- */
@media (max-width: 768px) {
    .hero h2 {
        font-size: 2rem;
    }
    nav {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        margin-top: 0.5rem;
    }
}