:root {
    /* Light Mode Variables */
    --primary-color: #3f51b5; /* Indigo 500 */
    --primary-dark: #303f9f; /* Indigo 700 */
    --secondary-color: #009688; /* Teal 500 */
    --secondary-dark: #00796b; /* Teal 700 */
    --bg-color: #f5f5f5; /* Grey 100 */
    --surface-color: #ffffff;
    --text-color: #212121; /* Grey 900 */
    --text-secondary: #757575; /* Grey 600 */
    --border-color: #e0e0e0;
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
}

[data-theme="dark"] {
    /* Dark Mode Variables */
    --primary-color: #7986cb; /* Indigo 300 */
    --primary-dark: #5c6bc0; /* Indigo 400 */
    --secondary-color: #4db6ac; /* Teal 300 */
    --secondary-dark: #26a69a; /* Teal 400 */
    --bg-color: #121212;
    --surface-color: #1e1e1e;
    --text-color: #ffffff;
    --text-secondary: #b0bec5;
    --border-color: #333333;
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.3);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.3);
}

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

body {
    font-family: 'Roboto', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navbar */
.navbar {
    background-color: var(--surface-color);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 1rem 0;
    transition: background-color 0.3s ease;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
    letter-spacing: 0.5px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 20px;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.2s;
}

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

/* Theme Toggle */
.icon-button {
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-color);
    transition: background-color 0.2s;
}

.icon-button:hover {
    background-color: rgba(128, 128, 128, 0.1);
}

.sun-icon {
    display: none;
    fill: currentColor;
}

.moon-icon {
    display: block;
    fill: currentColor;
}

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

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

/* Hero Section */
.hero {
    padding: 80px 0;
    text-align: center;
    background: linear-gradient(135deg, var(--surface-color) 0%, var(--bg-color) 100%);
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
}

.cta-group {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

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

.btn-primary:hover {
    background-color: var(--primary-dark);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: transparent;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.btn-secondary:hover {
    background-color: rgba(63, 81, 181, 0.04);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

/* Cards & Sections */
.card {
    background-color: var(--surface-color);
    border-radius: 8px;
    padding: 40px;
    margin: 40px 0;
    box-shadow: var(--shadow-sm);
    transition: background-color 0.3s ease;
}

.card h2 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: var(--text-color);
    border-bottom: 2px solid var(--secondary-color);
    display: inline-block;
    padding-bottom: 0.5rem;
}

.milestone-content {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.milestone-text {
    font-size: 1.1rem;
}

.progress-indicator {
    background-color: var(--bg-color);
    padding: 20px;
    border-radius: 8px;
    text-align: center;
}

.target {
    display: block;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.progress-bar-bg {
    background-color: var(--border-color);
    height: 10px;
    border-radius: 5px;
    overflow: hidden;
    margin-bottom: 10px;
}

.progress-bar-fill {
    background-color: var(--secondary-color);
    height: 100%;
    border-radius: 5px;
    transition: width 1s ease-in-out;
}

.small-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.email-link {
    display: inline-block;
    margin-top: 1rem;
    font-size: 1.2rem;
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 500;
}

.email-link:hover {
    text-decoration: underline;
}

/* Footer */
.footer {
    background-color: var(--surface-color);
    padding: 40px 0;
    text-align: center;
    margin-top: 60px;
    border-top: 1px solid var(--border-color);
}

.footer p {
    color: var(--text-secondary);
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
}

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .subtitle {
        font-size: 1.2rem;
    }

    .cta-group {
        flex-direction: column;
    }

    .nav-links {
        gap: 10px;
    }
    
    .nav-links a {
        font-size: 0.9rem;
    }
}