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

:root {
    /* Color Palette */
    --primary-color: #ff6b9d;
    --primary-light: #ffb3d1;
    --primary-dark: #e91e63;
    --secondary-color: #4ecdc4;
    --accent-color: #ffd93d;
    
    /* Neutral Colors */
    --text-primary: #2c3e50;
    --text-secondary: #7f8c8d;
    --text-light: #bdc3c7;
    --background: #ffffff;
    --background-light: #f8f9fa;
    --border-color: #e9ecef;
    --shadow-light: rgba(0, 0, 0, 0.1);
    --shadow-medium: rgba(0, 0, 0, 0.15);
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* App Container */
#app {
    min-height: 100vh;
    position: relative;
}

.app-container {
    max-width: 480px;
    margin: 0 auto;
    padding: var(--spacing-md);
    min-height: 100vh;
    background: linear-gradient(135deg, #ffeef8 0%, #f0f8ff 100%);
}

/* Loading State */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    text-align: center;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: var(--spacing-md);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Header */
.header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-lg) 0;
}

.greeting-text {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    color: var(--primary-dark);
    margin-bottom: var(--spacing-sm);
    line-height: 1.3;
}

.badge-name {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    font-weight: 500;
}

/* Main Content */
.main-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

/* Knowledge Card */
.knowledge-card-section {
    margin-bottom: var(--spacing-lg);
}

.knowledge-card {
    background: var(--background);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    box-shadow: 0 4px 20px var(--shadow-light);
    border: 1px solid var(--border-color);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.knowledge-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px var(--shadow-medium);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
}

.card-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
}

.refresh-btn {
    background: var(--primary-light);
    border: none;
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
}

.refresh-btn:hover {
    background: var(--primary-color);
    transform: rotate(180deg);
}

.refresh-btn:active {
    transform: rotate(180deg) scale(0.95);
}

.refresh-icon {
    font-size: var(--font-size-lg);
}

.card-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.card-image {
    width: 100%;
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: var(--background-light);
    min-height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.card-image img {
    width: 100%;
    height: auto;
    object-fit: cover;
}

.card-content-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.card-content-text {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Thank Wall Section */
.thank-wall-section {
    background: var(--background);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    box-shadow: 0 4px 20px var(--shadow-light);
    border: 1px solid var(--border-color);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
}

.section-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
}

.add-message-btn {
    background: var(--secondary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.add-message-btn:hover {
    background: #45b7aa;
    transform: translateY(-1px);
}

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

/* Message Form */
.message-form {
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background: var(--background-light);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.message-input {
    width: 100%;
    min-height: 80px;
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: var(--font-size-base);
    line-height: 1.5;
    resize: vertical;
    transition: border-color var(--transition-fast);
}

.message-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(255, 107, 157, 0.1);
}

.form-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: var(--spacing-md);
}

.char-count {
    font-size: var(--font-size-sm);
    color: var(--text-light);
}

.form-buttons {
    display: flex;
    gap: var(--spacing-sm);
}

/* Buttons */
.btn {
    padding: var(--spacing-sm) var(--spacing-md);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 36px;
}

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

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

.btn-secondary {
    background: var(--background);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--background-light);
    border-color: var(--text-light);
}

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

/* Messages List */
.messages-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    max-height: 400px;
    overflow-y: auto;
}

.message-item {
    padding: var(--spacing-md);
    background: var(--background-light);
    border-radius: var(--radius-lg);
    border-left: 3px solid var(--accent-color);
    transition: transform var(--transition-fast);
}

.message-item:hover {
    transform: translateX(2px);
}

.message-content {
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
    line-height: 1.6;
}

.message-time {
    font-size: var(--font-size-xs);
    color: var(--text-light);
}

/* Settings */
.settings-trigger {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    width: 50px;
    height: 50px;
    background: var(--primary-color);
    border: none;
    border-radius: 50%;
    font-size: var(--font-size-lg);
    cursor: pointer;
    box-shadow: 0 4px 20px var(--shadow-medium);
    transition: all var(--transition-normal);
    z-index: 100;
}

.settings-trigger:hover {
    background: var(--primary-dark);
    transform: scale(1.1);
}

.settings-modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: var(--spacing-md);
}

.settings-content {
    background: var(--background);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    width: 100%;
    max-width: 400px;
    max-height: 90vh;
    overflow-y: auto;
}

.settings-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
}

.settings-header h2 {
    font-size: var(--font-size-xl);
    color: var(--text-primary);
}

.close-btn {
    background: none;
    border: none;
    font-size: var(--font-size-2xl);
    cursor: pointer;
    color: var(--text-light);
    transition: color var(--transition-fast);
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.settings-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.form-group label {
    font-weight: 500;
    color: var(--text-primary);
}

.form-input {
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: var(--font-size-base);
    transition: border-color var(--transition-fast);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(255, 107, 157, 0.1);
}

.form-hint {
    font-size: var(--font-size-xs);
    color: var(--text-light);
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    font-weight: normal;
}

.checkbox-label input[type="checkbox"] {
    display: none;
}

.checkbox-custom {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    position: relative;
    transition: all var(--transition-fast);
}

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

.checkbox-label input[type="checkbox"]:checked + .checkbox-custom::after {
    content: '✓';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-size: var(--font-size-xs);
    font-weight: bold;
}

/* Error State */
.error-state {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    text-align: center;
    padding: var(--spacing-xl);
}

.error-content h2 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.error-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

/* Responsive Design */
@media (max-width: 480px) {
    .app-container {
        padding: var(--spacing-sm);
    }
    
    .knowledge-card,
    .thank-wall-section {
        padding: var(--spacing-md);
    }
    
    .greeting-text {
        font-size: var(--font-size-xl);
    }
    
    .settings-modal {
        padding: var(--spacing-sm);
    }
    
    .settings-content {
        padding: var(--spacing-lg);
    }
}

@media (max-width: 360px) {
    .card-header {
        flex-direction: column;
        gap: var(--spacing-sm);
        align-items: flex-start;
    }
    
    .section-header {
        flex-direction: column;
        gap: var(--spacing-sm);
        align-items: flex-start;
    }
    
    .form-actions {
        flex-direction: column;
        gap: var(--spacing-sm);
        align-items: stretch;
    }
    
    .form-buttons {
        justify-content: stretch;
    }
    
    .form-buttons .btn {
        flex: 1;
    }
}

/* Touch Improvements */
@media (hover: none) and (pointer: coarse) {
    .btn,
    .refresh-btn,
    .add-message-btn,
    .settings-trigger {
        min-height: 44px;
        min-width: 44px;
    }
    
    .message-item:hover {
        transform: none;
    }
    
    .knowledge-card:hover {
        transform: none;
        box-shadow: 0 4px 20px var(--shadow-light);
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Dark mode support (future enhancement) */
@media (prefers-color-scheme: dark) {
    :root {
        --text-primary: #ffffff;
        --text-secondary: #b0b0b0;
        --text-light: #808080;
        --background: #1a1a1a;
        --background-light: #2a2a2a;
        --border-color: #404040;
        --shadow-light: rgba(255, 255, 255, 0.1);
        --shadow-medium: rgba(255, 255, 255, 0.15);
    }
    
    .app-container {
        background: linear-gradient(135deg, #2a1a2a 0%, #1a2a3a 100%);
    }
}