/* CSS Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #d32f2f;
    --primary-dark: #b71c1c;
    --secondary-color: #f44336;
    --accent-color: #ff9800;
    --background-color: #fafafa;
    --surface-color: #ffffff;
    --text-primary: #212121;
    --text-secondary: #757575;
    --text-light: #ffffff;
    --border-color: #e0e0e0;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-light: 0 1px 3px rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', '微软雅黑', sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    font-size: 16px;
}

/* App Container */
#app {
    max-width: 500px;
    margin: 0 auto;
    background-color: var(--surface-color);
    min-height: 100vh;
    box-shadow: var(--shadow);
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--text-light);
    padding: 1rem;
    box-shadow: var(--shadow);
}

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

.app-title {
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: 0.5px;
}

.header-controls {
    display: flex;
    gap: 0.5rem;
}

/* Buttons */
.btn {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: var(--border-radius);
    font-family: inherit;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.btn-primary {
    background-color: var(--accent-color);
    color: var(--text-light);
}

.btn-primary:hover {
    background-color: #e65100;
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: rgba(255, 255, 255, 0.2);
    color: var(--text-light);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

.btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.3);
}

/* Navigation */
.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    background-color: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
}

.nav-btn {
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--primary-color);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    transition: var(--transition);
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.nav-btn:hover {
    background-color: var(--background-color);
    transform: scale(1.1);
}

.nav-date {
    text-align: center;
    flex: 1;
}

.month-year {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

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

/* Date Picker */
.date-picker-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 0.5rem;
}

.date-picker {
    padding: 0.25rem 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-family: inherit;
    font-size: 0.8rem;
    background-color: var(--surface-color);
    color: var(--text-primary);
    transition: var(--transition);
    width: 130px;
}

.date-picker:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(211, 47, 47, 0.1);
}

.goto-btn {
    padding: 0.25rem 0.75rem;
    background-color: var(--primary-color);
    color: var(--text-light);
    border: none;
    border-radius: 4px;
    font-family: inherit;
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

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

.goto-btn:active {
    transform: translateY(0);
}

/* Calendar */
.calendar-container {
    padding: 1rem;
}

.weekdays {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 1px;
    margin-bottom: 1rem;
}

.weekday {
    text-align: center;
    padding: 0.75rem 0;
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.calendar-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 1px;
    background-color: var(--border-color);
    border-radius: var(--border-radius);
    overflow: hidden;
}

.calendar-day {
    background-color: var(--surface-color);
    padding: 0.75rem 0.5rem;
    min-height: 80px;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.calendar-day:hover {
    background-color: var(--background-color);
    transform: scale(1.02);
}

.calendar-day.other-month {
    opacity: 0.3;
}

.calendar-day.today {
    background-color: var(--primary-color);
    color: var(--text-light);
}

.calendar-day.today:hover {
    background-color: var(--primary-dark);
}

.solar-date {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.lunar-date-small {
    font-size: 0.7rem;
    color: var(--text-secondary);
    text-align: center;
    line-height: 1.2;
}

.calendar-day.today .lunar-date-small {
    color: rgba(255, 255, 255, 0.8);
}

.festival-indicator {
    position: absolute;
    top: 4px;
    right: 4px;
    width: 8px;
    height: 8px;
    background-color: var(--accent-color);
    border-radius: 50%;
}

.solar-term-indicator {
    position: absolute;
    top: 4px;
    left: 4px;
    width: 8px;
    height: 8px;
    background-color: #4caf50;
    border-radius: 50%;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 1rem;
}

.modal-content {
    background-color: var(--surface-color);
    border-radius: var(--border-radius);
    max-width: 400px;
    width: 100%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.modal-title {
    font-size: 1.2rem;
    font-weight: 600;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 0.25rem;
    border-radius: 50%;
    transition: var(--transition);
}

.close-btn:hover {
    background-color: var(--background-color);
    color: var(--text-primary);
}

.modal-body {
    padding: 1rem;
}

.lunar-info, .zodiac-info, .festivals-info, .solar-term-info {
    margin-bottom: 1rem;
    padding: 0.75rem;
    background-color: var(--background-color);
    border-radius: var(--border-radius);
}

.lunar-info h4, .zodiac-info h4, .festivals-info h4, .solar-term-info h4 {
    margin-bottom: 0.5rem;
    color: var(--primary-color);
    font-weight: 600;
}

/* Help Modal Styles */
.help-section {
    margin-bottom: 1.5rem;
    padding: 0.75rem;
    background-color: var(--background-color);
    border-radius: var(--border-radius);
}

.help-section h4 {
    margin-bottom: 0.75rem;
    color: var(--primary-color);
    font-weight: 600;
    font-size: 1rem;
}

.help-section ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.help-section li {
    padding: 0.25rem 0;
    font-size: 0.9rem;
    line-height: 1.4;
}

.help-section strong {
    background-color: var(--primary-color);
    color: var(--text-light);
    padding: 0.1rem 0.3rem;
    border-radius: 3px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* Offline Indicator */
.offline-indicator {
    position: fixed;
    bottom: 1rem;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--text-secondary);
    color: var(--text-light);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.8rem;
    z-index: 1001;
}

/* Date Navigation Feedback */
.date-navigation-feedback {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) translateY(-20px);
    background-color: var(--primary-color);
    color: var(--text-light);
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    font-weight: 500;
    box-shadow: var(--shadow);
    z-index: 1002;
    opacity: 0;
    transition: all 0.3s ease;
    pointer-events: none;
}

.date-navigation-feedback.error {
    background-color: #f44336;
}

/* Responsive Design */
@media (max-width: 480px) {
    .header {
        padding: 0.75rem;
    }
    
    .app-title {
        font-size: 1.25rem;
    }
    
    .nav {
        padding: 0.75rem;
    }
    
    .calendar-container {
        padding: 0.75rem;
    }
    
    .calendar-day {
        min-height: 70px;
        padding: 0.5rem 0.25rem;
    }
    
    .solar-date {
        font-size: 0.9rem;
    }
    
    .lunar-date-small {
        font-size: 0.65rem;
    }
    
    .date-picker-container {
        flex-direction: column;
        gap: 0.25rem;
        margin-top: 0.25rem;
    }
    
    .date-picker {
        width: 120px;
        font-size: 0.75rem;
    }
    
    .goto-btn {
        font-size: 0.75rem;
        padding: 0.2rem 0.5rem;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .version-info,
    .copyright {
        font-size: 0.7rem;
    }
}

@media (min-width: 501px) {
    #app {
        margin-top: 2rem;
        margin-bottom: 2rem;
        border-radius: var(--border-radius);
        min-height: calc(100vh - 4rem);
    }
}

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

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 500px;
    margin: 0 auto;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.version-info {
    font-family: 'Courier New', monospace;
    background-color: transparent;
    color: var(--text-secondary);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 400;
    opacity: 0.6;
}

.copyright {
    font-size: 0.75rem;
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
    :root {
        --background-color: #121212;
        --surface-color: #1e1e1e;
        --text-primary: #e0e0e0;
        --text-secondary: #9e9e9e;
        --border-color: #333333;
    }
    
    .calendar-day {
        border: 1px solid var(--border-color);
    }
    
    .calendar-day:hover {
        background-color: #2a2a2a;
    }
}

/* Print styles */
@media print {
    .header-controls,
    .offline-indicator,
    .footer,
    .modal {
        display: none !important;
    }
    
    #app {
        box-shadow: none;
        max-width: none;
    }
    
    .calendar-day {
        min-height: 60px;
        font-size: 0.8rem;
    }
}