/* CSS Variables for Light / Dark Mode */
:root {
    --bg-color: #f8fafc;
    --text-color: #1e293b;
    --card-bg: #ffffff;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --border-color: #e2e8f0;
    --footer-bg: #1e293b;
    --footer-text: #ffffff;
}

[data-theme="dark"] {
    --bg-color: #0f172a;
    --text-color: #f1f5f9;
    --card-bg: #1e293b;
    --accent-color: #60a5fa;
    --accent-hover: #3b82f6;
    --border-color: #334155;
    --footer-bg: #020617;
    --footer-text: #94a3b8;
}

/* Global Reset */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    transition: background-color 0.3s ease, color 0.3s ease;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

/* Header & Navigation */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 5%;
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    font-size: 1.25rem;
    font-weight: bold;
    color: var(--accent-color);
}

nav {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

nav a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
}

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

#theme-toggle {
    background: none;
    border: 1px solid var(--border-color);
    cursor: pointer;
    font-size: 1.1rem;
    padding: 0.3rem 0.6rem;
    border-radius: 50%;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 6rem 1rem;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.highlight {
    color: var(--accent-color);
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* Buttons */
.btn {
    display: inline-block;
    background-color: var(--accent-color);
    color: #ffffff;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: bold;
    border: none;
    cursor: pointer;
}

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

/* Sections & Containers */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

.container h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    text-align: center;
}

/* Skills Grid */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
}

.skill-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    text-align: center;
    border-radius: 8px;
    font-weight: 600;
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
}

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

.project-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 2rem;
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.project-card h3 {
    margin-bottom: 0.5rem;
}

.project-card p {
    margin-bottom: 1.5rem;
    opacity: 0.8;
}

.project-card a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: bold;
}

/* Contact Form */
#contact-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    max-width: 500px;
    margin: 0 auto;
}

#contact-form input,
#contact-form textarea {
    padding: 0.75rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background-color: var(--card-bg);
    color: var(--text-color);
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    background-color: var(--footer-bg);
    color: var(--footer-text);
    margin-top: 4rem;
}