:root {
    --primary-color: #005249; /* Deep Green */
    --secondary-color: #008272; /* Lighter Green */
    
    /* Light Theme (Default) */
    --bg-color: #f0f2f5;
    --font-color: #333;
    --card-bg-color: #ffffff;
    --header-bg-color: var(--primary-color);
    --header-font-color: #ffffff;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --border-color: #ddd;
    --modal-bg-color: #ffffff;
    
    --border-radius: 8px;
    --transition-speed: 0.3s;
}

body[data-theme="dark"] {
    /* Dark Theme */
    --bg-color: #1a1a1a;
    --font-color: #e0e0e0;
    --card-bg-color: #2c2c2c;
    --header-bg-color: #1f1f1f;
    --header-font-color: #e0e0e0;
    --shadow-color: rgba(0, 0, 0, 0.4);
    --border-color: #444;
    --modal-bg-color: #333;
}

body {
    font-family: 'Noto Sans KR', sans-serif;
    margin: 0;
    background-color: var(--bg-color);
    color: var(--font-color);
    line-height: 1.6;
    transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.site-header {
    background-color: var(--header-bg-color);
    color: var(--header-font-color);
    padding: 1rem 0;
    box-shadow: 0 2px 5px var(--shadow-color);
    transition: background-color var(--transition-speed) ease;
}

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

.site-title {
    margin: 0;
    font-size: 2rem;
    font-weight: 700;
}

/* Theme Toggle Button */
.theme-toggle {
    background: none;
    border: 2px solid var(--header-font-color);
    color: var(--header-font-color);
    width: 45px;
    height: 45px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.5rem;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: transform 0.3s ease, background-color 0.3s ease;
    margin-left: auto;
    margin-right: 20px;
}

.theme-toggle:hover {
    transform: scale(1.1) rotate(15deg);
}


/* Buttons */
.button-primary {
    background-color: var(--secondary-color);
    color: #fff;
    border: none;
    padding: 12px 20px;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 700;
    transition: background-color 0.3s ease, transform 0.2s ease;
}

.button-primary:hover {
    background-color: #00645a;
    transform: translateY(-2px);
}

/* Main Content */
#post-container {
    padding-top: 40px;
    padding-bottom: 40px;
}

/* Post Card Web Component */
post-card {
    display: block;
    background-color: var(--card-bg-color);
    border-radius: var(--border-radius);
    box-shadow: 0 4px 15px var(--shadow-color);
    margin-bottom: 30px;
    overflow: hidden;
    transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease, background-color var(--transition-speed) ease;
}

post-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

/* Modal */
.modal-wrapper {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal-content {
    background-color: var(--modal-bg-color);
    padding: 40px;
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 600px;
    position: relative;
    box-shadow: 0 5px 20px rgba(0,0,0,0.3);
    transition: background-color var(--transition-speed) ease;
}

.close-btn {
    position: absolute;
    top: 15px;
    right: 20px;
    font-size: 2rem;
    color: #aaa;
    cursor: pointer;
    transition: color 0.3s ease;
}

.close-btn:hover {
    color: var(--font-color);
}

/* Form */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 700;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--font-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-family: 'Noto Sans KR', sans-serif;
    transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 5px var(--secondary-color);
}

/* Responsive */
@media (max-width: 600px) {
    .site-title {
        font-size: 1.5rem;
    }
    .button-primary {
        padding: 10px 15px;
        font-size: 0.9rem;
    }
    .modal-content {
        padding: 20px;
    }
    .theme-toggle {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }
}