/* CSS Variables */
:root {
    --color-bg: #f9fafb;
    --color-text: #222222;
    --color-primary: #16a34a;
    --color-primary-light: #4ade80;
    --color-header-bg: #1e293b;
    --color-header-text: var(--color-primary-light);
    --color-hero-bg-start: #4ade80;
    --color-hero-bg-end: #16a34a;
    --color-info-bg: white;
    --color-info-text: #444;
    --color-footer-bg: #1e293b;
    --color-footer-text: #94a3b8;
    --color-btn-primary-bg: var(--color-primary-light);
    --color-btn-primary-text: var(--color-header-bg);
    --color-btn-primary-hover-bg: #22c55e;
    --color-btn-primary-hover-text: white;
    --color-btn-secondary-border: white;
    --color-btn-secondary-text: white;
    --color-btn-secondary-hover-bg: white;
    --color-btn-secondary-hover-text: var(--color-primary);
    --color-btn-outline-border: var(--color-primary-light);
    --color-btn-outline-text: var(--color-primary-light);
    --color-btn-outline-hover-bg: var(--color-primary-light);
    --color-btn-outline-hover-text: var(--color-header-bg);
}

/* Dark Mode */
body.dark {
    --color-bg: #121212;
    --color-text: #e1e1e1;
    --color-primary: #22c55e;
    --color-primary-light: #4ade80;
    --color-header-bg: #0f172a;
    --color-hero-bg-start: #166534;
    --color-hero-bg-end: #4ade80;
    --color-info-bg: #1e293b;
    --color-info-text: #cbd5e1;
    --color-footer-bg: #0f172a;
    --color-footer-text: #64748b;
}

/* Reset and Base Styles */
*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
        Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Layout */
.container {
    width: 90%;
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

/* Header Styles */
header {
    background-color: var(--color-header-bg);
    padding: 20px 0;
    box-shadow: 0 2px 6px rgb(0 0 0 / 0.1);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-header-text);
    text-decoration: none;
    user-select: none;
    letter-spacing: 1.5px;
    transition: color 0.3s ease;
}

.logo:hover,
.logo:focus {
    color: var(--color-btn-primary-hover-bg);
    outline: none;
}

/* Navigation and Buttons */
nav a {
    font-weight: 600;
    text-decoration: none;
    padding: 10px 22px;
    border-radius: 6px;
    cursor: pointer;
    user-select: none;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.btn-primary {
    background-color: var(--color-btn-primary-bg);
    color: var(--color-btn-primary-text);
    border: none;
}

.btn-primary:hover,
.btn-primary:focus {
    background-color: var(--color-btn-primary-hover-bg);
    color: var(--color-btn-primary-hover-text);
    outline: none;
}

.btn-secondary {
    background-color: transparent;
    border: 2.5px solid var(--color-btn-secondary-border);
    color: var(--color-btn-secondary-text);
    font-weight: 600;
    font-size: 1rem;
    padding: 12px 36px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease, color 0.3s ease;
    display: inline-block;
    text-decoration: none;
}

.btn-secondary:hover,
.btn-secondary:focus {
    background-color: var(--color-btn-secondary-hover-bg);
    color: var(--color-btn-secondary-hover-text);
    outline: none;
}

.btn-outline {
    background: transparent;
    border: 2.5px solid var(--color-btn-outline-border);
    color: var(--color-btn-outline-text);
    font-weight: 700;
    font-size: 1.1rem;
    padding: 8px 18px;
    border-radius: 8px;
    cursor: pointer;
    margin-right: 12px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.btn-outline:hover,
.btn-outline:focus {
    background-color: var(--color-btn-outline-hover-bg);
    color: var(--color-btn-outline-hover-text);
    outline: none;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--color-hero-bg-start) 0%, var(--color-hero-bg-end) 100%);
    color: var(--color-btn-secondary-text);
    padding: 80px 20px;
    border-radius: 12px;
    text-align: center;
    margin: 40px auto 60px;
    max-width: 900px;
    box-shadow: 0 12px 30px rgb(34 197 94 / 0.3);
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    font-weight: 500;
}

/* Info Sections */
.main-content {
    margin-bottom: 80px;
}

.info-section {
    background: var(--color-info-bg);
    color: var(--color-info-text);
    padding: 32px 28px;
    margin-bottom: 36px;
    border-radius: 12px;
    box-shadow: 0 8px 24px rgb(0 0 0 / 0.08);
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.info-section.visible {
    opacity: 1;
    transform: translateY(0);
}

.info-section h2 {
    color: var(--color-primary);
    margin-top: 0;
    margin-bottom: 1rem;
    font-weight: 700;
    font-size: 1.75rem;
}

.info-section p,
.info-section ul {
    font-size: 1.1rem;
    line-height: 1.7;
}

.info-section ul {
    padding-left: 1.4rem;
}

.info-section ul li {
    margin-bottom: 0.8rem;
}

/* Footer */
footer {
    background-color: var(--color-footer-bg);
    padding: 20px 0;
    color: var(--color-footer-text);
    font-size: 0.9rem;
    user-select: none;
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 900px;
    margin: 0 auto;
}

footer nav a {
    color: var(--color-footer-text);
    text-decoration: none;
    margin-left: 24px;
    font-weight: 500;
    transition: color 0.3s ease;
}

footer nav a:hover,
footer nav a:focus {
    color: var(--color-primary-light);
    outline: none;
}

/* Responsive */
@media (max-width: 600px) {
    .header-inner {
        flex-direction: column;
        gap: 12px;
    }

    .footer-inner {
        flex-direction: column;
        gap: 12px;
        text-align: center;
    }

    .hero h1 {
        font-size: 2.25rem;
    }

    .hero .subtitle {
        font-size: 1rem;
    }

    .info-section {
        padding: 24px 20px;
    }
}