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

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 2rem 1rem;
    color: var(--text-primary);
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 3rem;
    animation: fadeInDown 0.6s ease-out;
}

.header h1 {
    color: white;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.header p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.1rem;
}

/* Main Content Grid */
.main-grid {
    display: grid;
    grid-template-columns: 450px 1fr;
    gap: 2rem;
    animation: fadeInUp 0.6s ease-out;
}

@media (max-width: 1024px) {
    .main-grid {
        grid-template-columns: 1fr;
    }
}

/* Card Styles */
.card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: var(--shadow-xl);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 25px 30px -5px rgba(0, 0, 0, 0.15);
}

.card-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.card-title::before {
    content: '';
    display: inline-block;
    width: 4px;
    height: 24px;
    background: linear-gradient(180deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

/* Form Styles */
.form-section {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

/* Daily Activity Cards */
.day-activity-card {
    background: linear-gradient(135deg, #f8fafc, #f1f5f9);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    transition: all 0.3s ease;
}

.day-activity-card:hover {
    border-color: var(--primary-color);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.1);
}

.day-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary-color);
}

.time-period-section {
    margin-bottom: 1.25rem;
}

.time-period-section:last-child {
    margin-bottom: 0;
}

.period-header {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
    padding: 0.5rem;
    background: white;
    border-radius: 6px;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

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

.section-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-hint {
    display: block;
    margin-top: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.date-range-display {
    margin-top: 1rem;
    padding: 1rem;
    background: linear-gradient(135deg, #667eea20, #764ba220);
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
}

.date-range-label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.date-range-text {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--primary-color);
}

.form-label {
    display: block;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

.form-label.required::after {
    content: '*';
    color: var(--danger-color);
    margin-left: 0.25rem;
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 0.95rem;
    transition: all 0.3s ease;
    background: white;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-control:hover {
    border-color: var(--primary-color);
}

/* Radio Group */
.radio-group {
    display: flex;
    gap: 1rem;
}

.radio-option {
    flex: 1;
}

.radio-option input[type="radio"] {
    display: none;
}

.radio-option label {
    display: block;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
}

.radio-option input[type="radio"]:checked + label {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.radio-option label:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

/* Button */
.btn {
    padding: 1rem 2rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    width: 100%;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* Loading Spinner */
.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Result Area */
.result-area {
    min-height: 400px;
    max-height: 80vh;
    overflow-y: auto;
}

.result-area::-webkit-scrollbar {
    width: 8px;
}

.result-area::-webkit-scrollbar-track {
    background: #f1f5f9;
    border-radius: 4px;
}

.result-area::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-secondary);
}

.empty-state-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.empty-state h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

/* Week Tabs */
.week-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
    overflow-x: auto;
    padding-bottom: 0.5rem;
}

.week-tab {
    padding: 0.75rem 1.5rem;
    background: white;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
    font-weight: 500;
}

.week-tab:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

.week-tab.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-color: transparent;
}

.week-tab-day {
    display: block;
    font-size: 0.9rem;
}

.week-tab-date {
    display: block;
    font-size: 0.8rem;
    margin-top: 0.25rem;
    opacity: 0.8;
}

/* Progress Bar */
.progress-container {
    margin-bottom: 2rem;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #e2e8f0;
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    transition: width 0.3s ease;
    border-radius: 4px;
}

.progress-text {
    text-align: center;
    margin-top: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* Lesson Plan Display */
.lesson-plan {
    animation: fadeIn 0.5s ease-out;
}

.lesson-header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 2rem;
    border-radius: 12px;
    margin-bottom: 2rem;
}

.lesson-header h2 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
}

.lesson-meta {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    font-size: 0.95rem;
}

.lesson-meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.lesson-section {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: #f8fafc;
    border-radius: 12px;
    border-left: 4px solid var(--primary-color);
}

.lesson-section h3 {
    color: var(--primary-color);
    font-size: 1.3rem;
    margin-bottom: 1rem;
}

.lesson-section h4 {
    color: var(--text-primary);
    font-size: 1.1rem;
    margin: 1rem 0 0.5rem;
}

.lesson-section p {
    line-height: 1.8;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.lesson-content {
    white-space: pre-wrap;
    line-height: 1.8;
    color: var(--text-primary);
}

/* Action Buttons */
.action-buttons {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
    flex-wrap: wrap;
}

.btn-secondary {
    background: white;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    padding: 0.75rem 1.5rem;
}

.btn-secondary:hover {
    background: var(--primary-color);
    color: white;
}

/* Alert Messages */
.alert {
    padding: 1rem 1.5rem;
    border-radius: 8px;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    animation: slideInDown 0.3s ease-out;
}

.alert-success {
    background: #d1fae5;
    color: #065f46;
    border-left: 4px solid var(--success-color);
}

.alert-error {
    background: #fee2e2;
    color: #991b1b;
    border-left: 4px solid var(--danger-color);
}

.alert-warning {
    background: #fef3c7;
    color: #92400e;
    border-left: 4px solid var(--warning-color);
}

/* Animations */
@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

@keyframes slideInDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive */
@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .card {
        padding: 1.5rem;
    }
    
    .radio-group {
        flex-direction: column;
    }
    
    .lesson-meta {
        grid-template-columns: 1fr;
    }
}