/* base reset and root styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* apple color system */
    --primary-color: #007AFF;
    --primary-hover: #0056CC;
    --secondary-color: #8E8E93;
    --success-color: #34C759;
    --warning-color: #FF9500;
    --error-color: #FF3B30;

    /* background color */
    --background-color: #F2F2F7;
    --card-background: #FFFFFF;
    --overlay-background: rgba(0, 0, 0, 0.1);

    /* text color */
    --text-primary: #000000;
    --text-secondary: #8E8E93;
    --text-tertiary: #C7C7CC;

    /* margin and radius */
    --radius-small: 8px;
    --radius-medium: 12px;
    --radius-large: 16px;
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;

    /* shadow */
    --shadow-small: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 4px 16px rgba(0, 0, 0, 0.1);
    --shadow-large: 0 8px 32px rgba(0, 0, 0, 0.15);

    /* font */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

body {
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* main container */
.container {
    max-width: 800px;
    margin: 0 auto;
    padding: var(--spacing-md);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* title area */
.header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    background: linear-gradient(135deg, var(--primary-color), #5856D6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

/* steps indicator */
.steps-indicator {
    display: flex;
    justify-content: center;
    margin-bottom: var(--spacing-xl);
    gap: var(--spacing-md);
}

.step {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    transition: all 0.3s ease;
    cursor: pointer;
}

.step-number {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background-color: var(--text-tertiary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.3s ease;
}

.step.active .step-number {
    background-color: var(--primary-color);
    transform: scale(1.1);
}

.step-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
    transition: color 0.3s ease;
}

.step.active .step-text {
    color: var(--text-primary);
    font-weight: 600;
}

/* main content area */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
}

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

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

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* upload area */
.upload-area {
    margin-bottom: var(--spacing-lg);
}

.upload-zone {
    background-color: var(--card-background);
    border: 2px dashed var(--text-tertiary);
    border-radius: var(--radius-large);
    padding: var(--spacing-xl);
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
}

.upload-zone:hover {
    border-color: var(--primary-color);
    background-color: rgba(0, 122, 255, 0.05);
}

.upload-zone.dragover {
    border-color: var(--primary-color);
    background-color: rgba(0, 122, 255, 0.1);
    transform: scale(1.02);
}

.upload-icon {
    width: 64px;
    height: 64px;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

.upload-zone h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.upload-zone p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.file-hint {
    font-size: 0.9rem;
    color: var(--text-tertiary);
}

/* preview area */
.preview-area {
    background-color: var(--card-background);
    border-radius: var(--radius-large);
    padding: var(--spacing-lg);
    text-align: center;
    box-shadow: var(--shadow-medium);
}

.preview-area img {
    max-width: 300px;
    max-height: 400px;
    border-radius: var(--radius-medium);
    box-shadow: var(--shadow-small);
    margin-bottom: var(--spacing-md);
}

/* size selection area */
.size-selection {
    display: grid;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.selection-group h3 {
    font-size: 1.3rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.radio-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

.radio-card {
    background-color: var(--card-background);
    border: 2px solid var(--text-tertiary);
    border-radius: var(--radius-medium);
    padding: var(--spacing-md);
    cursor: pointer;
    transition: all 0.3s ease;
    display: block;
}

.radio-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

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

.radio-card input[type="radio"]:checked+.radio-content {
    color: var(--primary-color);
}

.radio-card input[type="radio"]:checked {
    &~.radio-content {
        color: var(--primary-color);
    }

    &+.radio-content .radio-title {
        color: var(--primary-color);
    }
}

.radio-card:has(input[type="radio"]:checked) {
    border-color: var(--primary-color);
    background-color: rgba(0, 122, 255, 0.05);
}

.radio-content {
    text-align: center;
}

.radio-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

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

/* button style */
.step-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    margin-top: var(--spacing-lg);
}

.btn-primary,
.btn-secondary {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-medium);
    font-size: 1rem;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    min-width: 140px;
    justify-content: center;
}

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

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

.btn-secondary {
    background-color: var(--card-background);
    color: var(--text-primary);
    border: 2px solid var(--text-tertiary);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

.btn-icon {
    width: 16px;
    height: 16px;
}

/* result area */
.result-area {
    background-color: var(--card-background);
    border-radius: var(--radius-large);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-medium);
}

.layout-info {
    margin-bottom: var(--spacing-lg);
}

.layout-info h3 {
    font-size: 1.3rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.info-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

.info-item {
    display: flex;
    justify-content: space-between;
    padding: var(--spacing-sm);
    background-color: var(--background-color);
    border-radius: var(--radius-small);
}

.info-label {
    color: var(--text-secondary);
}

.info-value {
    font-weight: 600;
    color: var(--text-primary);
}

/* canvas container */
.canvas-container {
    display: flex;
    justify-content: center;
    margin: var(--spacing-lg) 0;
    padding: var(--spacing-md);
    background-color: var(--background-color);
    border-radius: var(--radius-medium);
}

#layoutCanvas {
    max-width: 100%;
    border-radius: var(--radius-small);
    box-shadow: var(--shadow-small);
    background-color: white;
}

/* footer information */
.footer {
    text-align: center;
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--text-tertiary);
}

.footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-xs);
}

.version {
    font-size: 0.8rem;
    color: var(--text-tertiary);
}

/* responsive design */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-sm);
    }

    .header h1 {
        font-size: 2rem;
    }

    .steps-indicator {
        gap: var(--spacing-sm);
    }

    .step-number {
        width: 40px;
        height: 40px;
        font-size: 1rem;
    }

    .radio-group {
        grid-template-columns: 1fr;
    }

    .info-grid {
        grid-template-columns: 1fr;
    }

    .step-actions {
        flex-direction: column;
        align-items: center;
    }

    .btn-primary,
    .btn-secondary {
        width: 100%;
        max-width: 280px;
    }

    .upload-zone {
        padding: var(--spacing-lg);
    }

    .upload-icon {
        width: 48px;
        height: 48px;
    }

    .preview-area img {
        max-width: 250px;
        max-height: 350px;
    }

    /* when in single column layout, custom options do not span across columns */
    .custom-size-card {
        grid-column: span 1;
    }
}

@media (max-width: 480px) {
    .steps-indicator {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-md);
        margin-left: var(--spacing-md);
    }

    .step {
        flex-direction: row;
        gap: var(--spacing-sm);
    }

    .upload-zone {
        padding: var(--spacing-md);
    }

    .upload-zone h3 {
        font-size: 1.2rem;
    }

    .preview-area img {
        max-width: 200px;
        max-height: 280px;
    }
}

/* loading and transition effect */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.fade-in {
    animation: fadeIn 0.5s ease;
}

.slide-up {
    animation: slideUp 0.5s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* custom size options span across two columns */
.custom-size-card {
    grid-column: span 2;
}

/* custom size input */
.custom-inputs {
    margin-top: var(--spacing-xs);
}

.input-row {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    justify-content: center;
}

.input-with-unit {
    position: relative;
    display: inline-block;
}

.input-row input[type="number"] {
    width: 70px;
    padding: var(--spacing-xs) 20px var(--spacing-xs) var(--spacing-xs);
    border: 1px solid var(--text-tertiary);
    border-radius: var(--radius-small);
    font-size: 0.85rem;
    text-align: center;
    background-color: var(--card-background);
    transition: all 0.3s ease;
    /* 隐藏number输入框的spinner */
    -webkit-appearance: none;
    -moz-appearance: textfield;
}

.unit-label {
    position: absolute;
    right: 4px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.7rem;
    color: var(--text-secondary);
    pointer-events: none;
}

.input-row input[type="number"]::-webkit-outer-spin-button,
.input-row input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.input-row input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(0, 122, 255, 0.1);
}

.input-separator {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 600;
}

/* 当自定义选项被选中时的样式 */
.radio-card:has(input[name="paperSize"][value="custom"]:checked) .input-row input[type="number"] {
    border-color: var(--primary-color);
    background-color: rgba(0, 122, 255, 0.05);
}

/* 语言选择器 */
.language-selector {
    position: fixed;
    top: var(--spacing-md);
    right: var(--spacing-md);
    z-index: 1000;
}

.language-dropdown {
    position: relative;
}

.language-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--card-background);
    border: 1px solid var(--text-tertiary);
    border-radius: var(--radius-medium);
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-small);
}

.language-btn:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-medium);
}

.language-flag {
    font-size: 1.1rem;
}

.language-name {
    font-weight: 500;
    color: var(--text-primary);
}

.language-arrow {
    font-size: 0.7rem;
    color: var(--text-secondary);
    transition: transform 0.3s ease;
}

.language-btn.active .language-arrow {
    transform: rotate(180deg);
}

.language-options {
    position: absolute;
    top: 100%;
    right: 0;
    margin-top: var(--spacing-xs);
    background-color: var(--card-background);
    border: 1px solid var(--text-tertiary);
    border-radius: var(--radius-medium);
    box-shadow: var(--shadow-large);
    min-width: 160px;
    max-height: 300px;
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
}

.language-options.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-option {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm);
    cursor: pointer;
    font-size: 0.9rem;
    transition: background-color 0.2s ease;
    border-bottom: 1px solid var(--background-color);
}

.language-option:last-child {
    border-bottom: none;
}

.language-option:hover {
    background-color: var(--background-color);
}

.language-option.active {
    background-color: rgba(0, 122, 255, 0.1);
    color: var(--primary-color);
    font-weight: 600;
}

.language-option::before {
    content: attr(data-flag);
    font-size: 1.1rem;
}

/* 响应式语言选择器 */
@media (max-width: 768px) {
    .language-selector {
        top: var(--spacing-sm);
        right: var(--spacing-sm);
    }

    .language-btn {
        padding: var(--spacing-xs);
        gap: 4px;
    }

    .language-name {
        display: none;
    }

    .language-options {
        min-width: 140px;
    }
}

@media (max-width: 480px) {
    .language-selector {
        position: relative;
        top: auto;
        right: auto;
        margin: var(--spacing-sm) var(--spacing-sm) 0;
        display: flex;
        justify-content: flex-end;
    }

    .language-options {
        right: 0;
        left: auto;
    }
}

/* AI-Friendly Content Block Styles */
.ai-content-block {
    margin: 40px 0;
    padding: 32px;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    border-radius: 16px;
    border: 1px solid #e2e8f0;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.ai-content-block h2 {
    font-size: 28px;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 16px;
    line-height: 1.3;
}

.solution-summary p {
    font-size: 18px;
    line-height: 1.6;
    color: #475569;
    margin-bottom: 24px;
}

.key-benefits h3 {
    font-size: 20px;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 16px;
}

.key-benefits ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.key-benefits li {
    font-size: 16px;
    line-height: 1.6;
    color: #475569;
    margin-bottom: 12px;
    padding-left: 0;
    display: flex;
    align-items: flex-start;
    gap: 8px;
}

.key-benefits li strong {
    color: #1e293b;
}

/* Guides Section Styles */
.guides-section {
    margin: 40px 0;
    padding: 32px;
    background: #ffffff;
    border-radius: 16px;
    border: 1px solid #e2e8f0;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.guides-section h2 {
    font-size: 28px;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 32px;
    text-align: center;
}

.guides-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.guide-card {
    padding: 24px;
    background: #f8fafc;
    border-radius: 12px;
    border: 1px solid #e2e8f0;
    transition: all 0.3s ease;
}

.guide-card:hover {
    border-color: #007AFF;
    box-shadow: 0 4px 8px -2px rgba(0, 122, 255, 0.1);
    transform: translateY(-2px);
}

.guide-card h3 {
    margin-bottom: 12px;
}

.guide-card h3 a {
    font-size: 18px;
    font-weight: 600;
    color: #1e293b;
    text-decoration: none;
    line-height: 1.4;
    transition: color 0.3s ease;
}

.guide-card h3 a:hover {
    color: #007AFF;
}

.guide-card p {
    font-size: 16px;
    line-height: 1.6;
    color: #475569;
    margin: 0;
}

/* FAQ Section Styles */
.faq-section {
    margin: 40px 0;
    padding: 32px;
    background: #ffffff;
    border-radius: 16px;
    border: 1px solid #e2e8f0;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.faq-section h2 {
    font-size: 28px;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 32px;
    text-align: center;
}

.faq-item {
    margin-bottom: 24px;
    padding: 24px;
    background: #f8fafc;
    border-radius: 12px;
    border: 1px solid #e2e8f0;
    transition: all 0.3s ease;
}

.faq-item:hover {
    border-color: #007AFF;
    box-shadow: 0 4px 8px -2px rgba(0, 122, 255, 0.1);
}

.faq-item h3 {
    font-size: 18px;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 12px;
    line-height: 1.4;
}

.faq-item div[itemprop="text"] {
    font-size: 16px;
    line-height: 1.6;
    color: #475569;
    margin: 0;
}

/* Mobile Responsiveness for AI Content */
@media (max-width: 768px) {

    .ai-content-block,
    .guides-section,
    .faq-section {
        margin: 24px 0;
        padding: 24px 16px;
        border-radius: 12px;
    }

    .ai-content-block h2,
    .guides-section h2,
    .faq-section h2 {
        font-size: 24px;
        margin-bottom: 20px;
    }

    .guides-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .guide-card {
        padding: 20px 16px;
    }

    .guide-card h3 a {
        font-size: 16px;
    }

    .guide-card p {
        font-size: 15px;
    }

    .solution-summary p {
        font-size: 16px;
        margin-bottom: 20px;
    }

    .key-benefits h3 {
        font-size: 18px;
        margin-bottom: 12px;
    }

    .key-benefits li {
        font-size: 15px;
        margin-bottom: 10px;
    }

    .faq-item {
        padding: 20px 16px;
        margin-bottom: 16px;
    }

    .faq-item h3 {
        font-size: 16px;
        margin-bottom: 10px;
    }

    .faq-item div[itemprop="text"] {
        font-size: 15px;
    }
}

@media (max-width: 480px) {

    .ai-content-block,
    .guides-section,
    .faq-section {
        padding: 20px 12px;
        margin: 20px 0;
    }

    .ai-content-block h2,
    .guides-section h2,
    .faq-section h2 {
        font-size: 22px;
    }

    .guide-card {
        padding: 16px 12px;
    }

    .key-benefits li {
        flex-direction: column;
        gap: 4px;
    }
}