:root {
    --font-family: 'Noto Sans KR', sans-serif;
    --primary-color: #5a67d8;
    --primary-color-dark: #434190;
    --background-light: #f7fafc;
    --background-dark: #1a202c;
    --text-light: #1a202c;
    --text-dark: #edf2f7;
    --card-bg-light: #ffffff;
    --card-bg-dark: #2d3748;
    --border-light: #e2e8f0;
    --border-dark: #4a5568;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --button-text-light: #ffffff;
    --button-text-dark: #edf2f7;
}

body {
    font-family: var(--font-family);
    margin: 0;
    transition: background-color 0.3s, color 0.3s;
}

body.light-mode {
    background-color: var(--background-light);
    color: var(--text-light);
}

body.dark-mode {
    background-color: var(--background-dark);
    color: var(--text-dark);
}

.app-container {
    max-width: 700px;
    margin: 0 auto;
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap; /* Allow header items to wrap on smaller screens */
}

header h1 {
    font-size: 2rem;
    font-weight: 700;
    margin: 0;
}

header nav {
    display: flex;
    gap: 10px; /* Space between nav buttons */
    align-items: center;
}

#theme-toggle-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: inherit;
    margin-left: 10px; /* Space from other nav buttons */
}

.nav-btn {
    background-color: transparent;
    border: 1px solid var(--border-light);
    color: inherit;
    padding: 8px 15px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s, border-color 0.2s;
}

.light-mode .nav-btn {
    border-color: var(--border-light);
}

.dark-mode .nav-btn {
    border-color: var(--border-dark);
}

.nav-btn.active {
    background-color: var(--primary-color);
    color: var(--button-text-light);
    border-color: var(--primary-color);
}

.light-mode .nav-btn:hover:not(.active) {
    background-color: var(--border-light);
}

.dark-mode .nav-btn:hover:not(.active) {
    background-color: var(--card-bg-dark);
}


.card {
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 4px 15px var(--shadow-color);
    margin-bottom: 20px;
    transition: background-color 0.3s;
}

.light-mode .card {
    background-color: var(--card-bg-light);
    border: 1px solid var(--border-light);
}

.dark-mode .card {
    background-color: var(--card-bg-dark);
    border: 1px solid var(--border-dark);
}

#input-section h2, #contact-section h2 {
    margin-top: 0;
    font-weight: 500;
}

.input-grid {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 15px;
    align-items: center;
    margin: 20px 0;
}

.input-grid label, .input-group label {
    font-weight: 500;
}

input[type="date"], 
input[type="time"],
input[type="text"],
input[type="email"],
textarea {
    width: 100%;
    padding: 10px;
    border-radius: 8px;
    border: 1px solid;
    font-family: var(--font-family);
    box-sizing: border-box; /* Include padding and border in the element's total width and height */
}

.input-group {
    margin-bottom: 15px;
}

.input-group label {
    display: block;
    margin-bottom: 5px;
}

.light-mode input, .light-mode textarea {
    border-color: var(--border-light);
    background-color: var(--background-light);
    color: var(--text-light);
}

.dark-mode input, .dark-mode textarea {
    border-color: var(--border-dark);
    background-color: var(--card-bg-dark);
    color: var(--text-dark);
}

button {
    font-family: var(--font-family);
    font-size: 1rem;
    font-weight: 500;
    padding: 12px 25px;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.2s;
}

button:hover {
    transform: translateY(-2px);
}

#view-fortune-btn, #submit-contact-btn {
    width: 100%;
    background-color: var(--primary-color);
}

.light-mode #view-fortune-btn, .light-mode #submit-contact-btn {
    color: var(--button-text-light);
}

.dark-mode #view-fortune-btn, .dark-mode #submit-contact-btn {
    color: var(--button-text-dark);
}

#view-fortune-btn:hover, #submit-contact-btn:hover {
    background-color: var(--primary-color-dark);
}

.tab-nav {
    display: flex;
    border-bottom: 2px solid;
    margin-bottom: 20px;
}

.light-mode .tab-nav {
    border-bottom-color: var(--border-light);
}

.dark-mode .tab-nav {
    border-bottom-color: var(--border-dark);
}

.tab-link {
    background: none;
    border: none;
    padding: 10px 15px;
    font-size: 1rem;
    cursor: pointer;
    color: inherit;
    border-bottom: 3px solid transparent;
    margin-bottom: -2px;
}

.tab-link.active {
    font-weight: 700;
    border-bottom-color: var(--primary-color);
}

.tab-content {
    display: none;
    animation: fadeIn 0.5s;
}

.tab-content.active {
    display: block;
}

.tab-content h3 {
    margin-top: 0;
}

#reset-btn {
    margin-top: 20px;
    background-color: #ccc;
    color: #333;
}

#contact-form-status {
    margin-top: 15px;
    text-align: center;
    font-weight: 500;
}

.hidden {
    display: none;
}

.fortune-section.hidden {
    display: none;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@media (max-width: 600px) {
    header {
        flex-direction: column;
        align-items: flex-start;
        gap: 15px;
    }
    header h1 {
        margin-bottom: 10px;
    }
    header nav {
        width: 100%;
        justify-content: space-between;
    }
    .nav-btn {
        flex-grow: 1;
        text-align: center;
    }
    #theme-toggle-btn {
        margin-left: 0;
    }
}