/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 根变量定义 */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #a5b4fc;
    --secondary-color: #f8fafc;
    --accent-color: #10b981;
    --accent-hover: #059669;
    --danger-color: #ef4444;
    --danger-hover: #dc2626;
    --warning-color: #f59e0b;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --border-color: #e5e7eb;
    --border-hover: #d1d5db;
    --background: #ffffff;
    --background-secondary: #f9fafb;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --border-radius: 12px;
    --border-radius-lg: 16px;
    --border-radius-sm: 8px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --animation-bounce: cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* 基础排版 */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
    min-height: 100vh;
    font-weight: 400;
}

/* 容器 */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

/* 头部 */
header {
    text-align: center;
    margin-bottom: 3rem;
    color: white;
    position: relative;
}

header::before {
    content: '';
    position: absolute;
    top: -20px;
    left: 50%;
    transform: translateX(-50%);
    width: 100px;
    height: 4px;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    border-radius: 2px;
}

header h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    text-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    letter-spacing: -0.02em;
}

header p {
    font-size: 1.2rem;
    opacity: 0.95;
    font-weight: 300;
    letter-spacing: 0.01em;
}

/* 主要内容区域 */
main {
    display: grid;
    gap: 2rem;
}

/* 通知系统 */
.notification {
    display: none;
    padding: 1rem 1.25rem;
    border-radius: var(--border-radius);
    font-weight: 500;
    margin-bottom: 1rem;
    animation: slideIn 0.3s ease-out;
}

.notification.show {
    display: block;
}

.notification.success {
    background: #d1fae5;
    color: #065f46;
    border: 1px solid #a7f3d0;
}

.notification.error {
    background: #fee2e2;
    color: #991b1b;
    border: 1px solid #fca5a5;
}

.notification.info {
    background: #dbeafe;
    color: #1e40af;
    border: 1px solid #93c5fd;
}

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

/* 区块样式 */
section {
    background: var(--background);
    border-radius: var(--border-radius-lg);
    padding: 2.5rem;
    box-shadow: var(--shadow-xl);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    position: relative;
    overflow: hidden;
}

section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.5), transparent);
}

section h2 {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2rem;
    position: relative;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

section h2::before {
    content: '';
    width: 4px;
    height: 24px;
    background: linear-gradient(180deg, var(--primary-color), var(--accent-color));
    border-radius: 2px;
}

/* 价格模式切换区域 */
.price-mode-section {
    background: var(--background-secondary);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    border: 2px solid var(--border-color);
    transition: var(--transition);
}

.section-label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: 1rem;
    display: block;
}

.price-mode-toggle {
    display: flex;
    background: var(--background);
    border-radius: var(--border-radius-sm);
    padding: 4px;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.mode-btn {
    flex: 1;
    padding: 0.75rem 1rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.mode-btn.active {
    background: var(--primary-color);
    color: white;
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.mode-btn:hover:not(.active) {
    background: var(--background-secondary);
    color: var(--text-primary);
}

.price-input-group {
    display: none;
    animation: fadeInUp 0.4s var(--animation-bounce);
}

.price-input-group.active {
    display: block;
}

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

/* 表单样式 */
.add-item-form {
    display: grid;
    gap: 2rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.form-group label {
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.95rem;
    letter-spacing: 0.01em;
}

.form-group input,
.form-group textarea {
    padding: 1rem 1.25rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
    background: var(--background);
    color: var(--text-primary);
    resize: vertical;
    min-height: 50px;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
    background: var(--background);
    transform: translateY(-1px);
}

.form-group input:hover:not(:focus),
.form-group textarea:hover:not(:focus) {
    border-color: var(--border-hover);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-muted);
}

.optional-label {
    color: var(--text-muted);
    font-weight: 400;
    font-size: 0.85rem;
}

.price-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
}

.add-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: var(--border-radius);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.add-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

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

.add-btn:hover::before {
    left: 100%;
}

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

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

.add-btn:disabled:hover {
    transform: none;
}

/* 购物清单区域 */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.header-actions {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    gap: 1rem;
}

.list-actions {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.action-btn {
    padding: 0.5rem 1rem;
    border: none;
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s ease, transform 0.1s ease;
}

.action-btn.secondary {
    background: var(--text-secondary);
    color: white;
}

.action-btn.secondary:hover {
    background: #4b5563;
    transform: translateY(-1px);
}

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

.action-btn.danger:hover {
    background: #dc2626;
    transform: translateY(-1px);
}

.total-price {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.25rem;
    background: linear-gradient(135deg, var(--accent-color), #059669);
    color: white;
    border-radius: var(--border-radius);
    font-weight: 500;
    box-shadow: var(--shadow);
}

.total-label {
    font-size: 0.9rem;
}

.total-amount {
    font-size: 1.1rem;
    font-weight: 600;
}

/* 购物清单 */
.shopping-list {
    display: grid;
    gap: 1rem;
}

.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--text-secondary);
    font-style: italic;
}

/* 商品项样式 */
.item {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    padding: 1.5rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--background);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(180deg, var(--primary-color), var(--accent-color));
    opacity: 0;
    transition: var(--transition);
}

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

.item:hover::before {
    opacity: 1;
}

.item-info {
    flex: 1;
    min-width: 0;
}

.item-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 0.75rem;
    gap: 1rem;
}

.item-name {
    font-weight: 600;
    font-size: 1.2rem;
    color: var(--text-primary);
    line-height: 1.3;
    word-break: break-word;
}

.item-price-badge {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.875rem;
    background: var(--background-secondary);
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--border-color);
    flex-shrink: 0;
}

.item-price-badge i {
    font-size: 0.9rem;
}

.price-text {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1rem;
}

.item-meta {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.item-note {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    margin: 0.5rem 0;
    padding: 0.5rem 0.75rem;
    background: var(--background-secondary);
    border-radius: var(--border-radius-sm);
    border-left: 3px solid var(--primary-color);
}

.item-note i {
    margin-top: 0.1rem;
    font-size: 0.8rem;
    flex-shrink: 0;
}

.item-note span {
    font-size: 0.9rem;
    line-height: 1.4;
    color: var(--text-secondary);
    word-break: break-word;
}

.item-actions {
    display: flex;
    gap: 0.75rem;
    align-items: flex-start;
    margin-left: 1rem;
}

.edit-btn, .delete-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1rem;
    border: none;
    border-radius: var(--border-radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

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

.edit-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

.delete-btn:hover {
    background: var(--danger-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* 编辑模式样式 */
.item.editing {
    background: linear-gradient(135deg, #fef3c7, #fbbf24);
    border-color: var(--warning-color);
    box-shadow: var(--shadow-lg);
}

.item.editing::before {
    background: linear-gradient(180deg, var(--warning-color), #f59e0b);
    opacity: 1;
}

.item.editing .item-info {
    display: none;
}

.edit-form {
    display: none;
    flex: 1;
    flex-direction: column;
    gap: 1rem;
    align-items: stretch;
    animation: slideInLeft 0.3s var(--animation-bounce);
}

.item.editing .edit-form {
    display: flex;
}

.edit-form-row {
    display: flex;
    gap: 0.75rem;
    align-items: flex-end;
    flex-wrap: wrap;
}

.edit-form input,
.edit-form textarea {
    flex: 1;
    min-width: 120px;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    font-size: 0.95rem;
    font-family: inherit;
    transition: var(--transition);
    background: var(--background);
    resize: vertical;
}

.edit-form input:focus,
.edit-form textarea:focus {
    outline: none;
    border-color: var(--warning-color);
    box-shadow: 0 0 0 3px rgba(245, 158, 11, 0.1);
}

.edit-form textarea {
    min-height: 60px;
    max-height: 120px;
    flex-basis: 100%;
}

.edit-form .price-inputs {
    display: flex;
    gap: 0.75rem;
    flex: 2;
    min-width: 200px;
}

.edit-form .action-buttons {
    display: flex;
    gap: 0.75rem;
    flex-shrink: 0;
}

.save-btn, .cancel-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    border: none;
    border-radius: var(--border-radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

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

.save-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.cancel-btn {
    background: var(--text-secondary);
    color: white;
}

.cancel-btn:hover {
    background: #4b5563;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
        max-width: 100%;
    }
    
    header h1 {
        font-size: 2.25rem;
    }
    
    header p {
        font-size: 1rem;
    }
    
    section {
        padding: 1.75rem;
        margin-bottom: 1.5rem;
    }
    
    section h2 {
        font-size: 1.5rem;
        margin-bottom: 1.5rem;
    }
    
    .price-group {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .price-mode-toggle {
        flex-direction: column;
        gap: 0.5rem;
        padding: 0.5rem;
    }
    
    .mode-btn {
        width: 100%;
        text-align: center;
    }
    
    .section-header {
        flex-direction: column;
        align-items: stretch;
        gap: 1.5rem;
    }
    
    .header-actions {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }
    
    .list-actions {
        justify-content: stretch;
        order: 2;
        flex-direction: column;
        gap: 0.75rem;
    }
    
    .action-btn {
        width: 100%;
        justify-content: center;
    }
    
    .total-price {
        justify-content: center;
        order: 1;
        flex-wrap: wrap;
        text-align: center;
    }
    
    .item {
        flex-direction: column;
        align-items: stretch;
        gap: 1.25rem;
        padding: 1.25rem;
    }
    
    .item-header {
        flex-direction: column;
        align-items: stretch;
        gap: 0.75rem;
    }
    
    .item-price-badge {
        align-self: flex-start;
    }
    
    .item-actions {
        justify-content: stretch;
        margin-left: 0;
        gap: 0.5rem;
    }
    
    .edit-btn, .delete-btn {
        flex: 1;
        justify-content: center;
    }
    
    .edit-form {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
    }
    
    .edit-form .price-inputs {
        flex-direction: column;
        gap: 0.75rem;
    }
    
    .save-btn, .cancel-btn {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0.75rem;
    }
    
    header {
        margin-bottom: 2rem;
    }
    
    header h1 {
        font-size: 1.875rem;
    }
    
    section {
        padding: 1.25rem;
        border-radius: var(--border-radius);
    }
    
    .add-item-form {
        gap: 1.5rem;
    }
    
    .form-group input {
        padding: 0.875rem 1rem;
        font-size: 1rem;
    }
    
    .add-btn {
        padding: 0.875rem 1.5rem;
        font-size: 1rem;
    }
    
    .item {
        padding: 1rem;
    }
    
    .item-name {
        font-size: 1.1rem;
    }
    
    .notification {
        margin: 0 -0.75rem 1rem -0.75rem;
        border-radius: 0;
    }
}

/* 大屏幕优化 */
@media (min-width: 1200px) {
    .container {
        max-width: 1000px;
        padding: 3rem 2rem;
    }
    
    header h1 {
        font-size: 3.5rem;
    }
    
    header p {
        font-size: 1.3rem;
    }
    
    section {
        padding: 3rem;
    }
    
    .item {
        padding: 2rem;
    }
    
    .item-name {
        font-size: 1.3rem;
    }
}