/* --- CSS Variables for Easy Theming --- */
:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --bg-main: #ffffff;
    --bg-light: #f3f4f6;
    --border-color: #e5e7eb;
    --font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    --transition-speed: 0.3s;
}

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

html {
    scroll-behavior: smooth;
}

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

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: color var(--transition-speed);
}

a:hover {
    color: var(--primary-hover);
}

ul {
    list-style-position: inside;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

.section-padding {
    padding: 80px 0;
}

.section-title {
    font-size: 2rem;
    margin-bottom: 30px;
    border-bottom: 2px solid var(--primary-color);
    display: inline-block;
    padding-bottom: 5px;
}

.bg-light {
    background-color: var(--bg-light);
}

.text-center {
    text-align: center;
}

/* --- Buttons --- */
.btn {
    display: inline-block;
    padding: 10px 20px;
    border-radius: 5px;
    font-weight: bold;
    cursor: pointer;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
    border: none;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    color: #fff;
}

.btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    margin-top: 15px;
}

.btn-outline:hover {
    background-color: var(--primary-color);
    color: #fff;
}

/* --- Navigation --- */
.navbar {
    background-color: var(--bg-main);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1100px;
    margin: 0 auto;
    padding: 15px 20px;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 20px;
}

.nav-links a {
    color: var(--text-main);
    font-weight: 500;
}

.nav-links a:hover {
    color: var(--primary-color);
}

/* --- Hero Section --- */
.hero-section {
    padding: 120px 0 80px;
    text-align: center;
}

.hero-section h1 {
    font-size: 3.5rem;
    margin-bottom: 10px;
}

.hero-section h2 {
    font-size: 1.5rem;
    color: var(--text-muted);
    font-weight: 400;
    margin-bottom: 20px;
}

.social-links {
    margin-top: 30px;
    display: flex;
    justify-content: center;
    gap: 20px;
    align-items: center;
}

/* --- Skills Grid --- */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.skill-category h3 {
    margin-bottom: 15px;
    color: var(--primary-color);
}

.skill-category ul {
    list-style: none;
}

.skill-category li {
    background-color: var(--bg-main);
    padding: 10px;
    margin-bottom: 8px;
    border-radius: 4px;
    border: 1px solid var(--border-color);
}

/* --- Projects Grid --- */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.project-card {
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 25px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: transform var(--transition-speed);
}

.project-card:hover {
    transform: translateY(-5px);
}

.tech-stack {
    font-size: 0.85rem;
    color: var(--primary-color);
    font-weight: bold;
    margin: 10px 0 15px;
}

.project-card ul {
    margin-bottom: 20px;
    color: var(--text-muted);
}

/* --- Experience & Education --- */
.timeline-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 40px;
}

@media (min-width: 768px) {
    .timeline-grid {
        grid-template-columns: 1fr 1fr;
    }
}

.timeline-item {
    background-color: var(--bg-main);
    padding: 20px;
    border-left: 4px solid var(--primary-color);
    margin-bottom: 20px;
    border-radius: 0 8px 8px 0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.timeline-item .date {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 10px;
    font-style: italic;
}

/* --- Footer --- */
.footer {
    background-color: var(--text-main);
    color: #fff;
    padding: 30px 0;
}