:root {
    --primary-color: #6b8e23; /* Olive Drab for a natural feel */
    --secondary-color: #f5f5dc; /* Beige background */
    --accent-color: #8fbc8f; /* Dark Sea Green */
    --text-color: #2f4f4f; /* Dark Slate Gray */
    --white: #ffffff;
    --card-bg: #ffffff;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    --transition: all 0.3s ease;
}

body.dark-mode {
    --primary-color: #9acd32; /* YellowGreen for better visibility */
    --secondary-color: #1a1a1a; /* Dark background */
    --accent-color: #2d4f2d; /* Darker green */
    --text-color: #e0e0e0; /* Light text */
    --white: #2c2c2c;
    --card-bg: #2c2c2c;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

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

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
    background-color: var(--secondary-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Header */
header {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: #ffffff; /* Header text usually stays light for contrast */
    padding: 4rem 1rem;
    text-align: center;
    margin-bottom: 3rem;
    position: relative;
}

.header-content h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.header-content p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* Theme Toggle */
.theme-toggle {
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
}

#theme-btn {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    padding: 0.8rem;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    transition: var(--transition);
    backdrop-filter: blur(5px);
}

#theme-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: rotate(20deg);
}

/* Container */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Step Card */
.step-card {
    background-color: var(--card-bg);
    border-radius: 20px;
    padding: 2rem;
    margin-bottom: 3rem;
    box-shadow: var(--shadow);
    position: relative;
    transition: var(--transition), background-color 0.3s ease;
}

.step-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.12);
}

.badge {
    position: absolute;
    top: -15px;
    left: 2rem;
    background-color: var(--primary-color);
    color: #ffffff;
    padding: 0.5rem 1.5rem;
    border-radius: 30px;
    font-weight: bold;
    font-size: 0.9rem;
    box-shadow: 0 4px 10px rgba(107, 142, 35, 0.3);
}

.content-wrapper {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 2rem;
    align-items: center;
}

@media (max-width: 768px) {
    .content-wrapper {
        grid-template-columns: 1fr;
    }
}

.image-area img {
    width: 100%;
    height: 300px;
    object-fit: cover;
    border-radius: 15px;
}

.text-area h2 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.en-name {
    font-size: 1rem;
    color: #888;
    font-weight: normal;
    font-style: italic;
}

.description {
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
}

.points {
    list-style: none;
    margin-bottom: 2rem;
}

.points li {
    position: relative;
    padding-left: 1.5rem;
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.points li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: bold;
}

.video-link {
    display: inline-block;
    background-color: #ff0000;
    color: #ffffff;
    text-decoration: none;
    padding: 0.8rem 1.5rem;
    border-radius: 10px;
    font-weight: bold;
    transition: var(--transition);
}

.video-link:hover {
    background-color: #cc0000;
    transform: scale(1.05);
}

.video-link i {
    margin-right: 0.5rem;
}

/* Completed State in Dark Mode */
body.dark-mode .step-card.completed {
    background-color: #1e291e;
}

/* Footer */
footer {
    text-align: center;
    padding: 3rem 1rem;
    color: #888;
    font-size: 0.9rem;
}