/* ============================================
   VSTSA-APP 营销网站样式表
   主题色: #5C87F6
   ============================================ */

/* CSS Variables */
:root {
    --primary-color: #5C87F6;
    --primary-dark: #4A6FD4;
    --primary-light: #7A9FF8;
    --primary-bg: #E8F0FE;
    --text-dark: #1F2937;
    --text-gray: #6B7280;
    --text-light: #9CA3AF;
    --bg-white: #FFFFFF;
    --bg-gray: #F9FAFB;
    --bg-gray-dark: #F3F4F6;
    --border-color: #E5E7EB;
    --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);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

ul {
    list-style: none;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header & Navigation */
.header {
    background: var(--bg-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 24px;
    gap: 32px;
}

.nav-brand a {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-img {
    width: 60px;
    height: 60px;
    object-fit: contain;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 32px;
    flex: 1;
    justify-content: center;
}

.nav-menu a {
    color: var(--text-gray);
    font-weight: 500;
    position: relative;
    padding: 8px 0;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--primary-color);
}

.nav-menu a.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary-color);
}

.nav-cta {
    padding: 10px 24px;
    font-size: 14px;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-dark);
    transition: var(--transition);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 16px;
    text-align: center;
    cursor: pointer;
    border: none;
    transition: var(--transition);
}

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

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

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

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

.btn-large {
    padding: 16px 32px;
    font-size: 18px;
}

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, var(--primary-bg) 0%, var(--bg-white) 100%);
}

.hero-split .hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    line-height: 1.2;
    color: var(--text-dark);
    margin-bottom: 16px;
}

.hero-subtitle {
    font-size: 28px;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 24px;
}

.hero-description {
    font-size: 18px;
    line-height: 1.8;
    color: var(--text-gray);
    margin-bottom: 32px;
}

.hero-cta {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hero-image img {
    width: 100%;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
}

/* Sections */
.section {
    padding: 80px 0;
}

.section-alt {
    background: var(--bg-gray);
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-title {
    font-size: 42px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 16px;
}

.section-subtitle {
    font-size: 20px;
    color: var(--text-gray);
}

/* Page Header */
.page-header {
    padding: 120px 0 60px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    text-align: center;
}

.page-header h1 {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 16px;
}

.page-header p {
    font-size: 20px;
    opacity: 0.9;
}

/* Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.feature-card {
    background: var(--bg-white);
    padding: 32px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    width: 64px;
    height: 64px;
    background: var(--primary-bg);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    margin-bottom: 24px;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.feature-card p {
    color: var(--text-gray);
    line-height: 1.6;
}

/* Content Split */
.content-split {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.content-split-reverse {
    direction: rtl;
}

.content-split-reverse > * {
    direction: ltr;
}

.content-image img {
    width: 100%;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.content-text .lead {
    font-size: 20px;
    line-height: 1.8;
    color: var(--text-gray);
    margin-bottom: 24px;
}

.benefits-list {
    margin-top: 32px;
}

.benefits-list li {
    margin-bottom: 24px;
    padding-left: 32px;
    position: relative;
}

.benefits-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: 700;
    font-size: 20px;
}

.benefits-list strong {
    display: block;
    font-size: 18px;
    color: var(--text-dark);
    margin-bottom: 8px;
}

.benefits-list p {
    color: var(--text-gray);
}

/* Calculators Grid */
.calculators-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
}

.calculator-card {
    background: var(--bg-white);
    padding: 40px 32px;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    border: 2px solid transparent;
}

.calculator-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.calculator-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    font-weight: 700;
    margin: 0 auto 24px;
}

.calculator-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.calculator-card p {
    color: var(--text-gray);
    line-height: 1.6;
}

/* Use Cases */
.use-cases {
    display: flex;
    flex-direction: column;
    gap: 48px;
}

.use-case-item {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: center;
}

.use-case-reverse {
    direction: rtl;
}

.use-case-reverse > * {
    direction: ltr;
}

.use-case-image img {
    width: 100%;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.use-case-content h3 {
    font-size: 28px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-dark);
}

.use-case-content p {
    font-size: 18px;
    line-height: 1.8;
    color: var(--text-gray);
}

/* Testimonials */
.testimonials {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

.testimonial-card {
    background: var(--bg-white);
    padding: 32px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.testimonial-content {
    margin-bottom: 24px;
}

.testimonial-content p {
    font-size: 18px;
    line-height: 1.8;
    color: var(--text-gray);
    font-style: italic;
}

.testimonial-author strong {
    display: block;
    font-size: 16px;
    color: var(--text-dark);
    margin-bottom: 4px;
}

.testimonial-author span {
    font-size: 14px;
    color: var(--text-light);
}

/* CTA Section */
.cta-section {
    padding: 80px 0;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    text-align: center;
}

.cta-content h2 {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 16px;
}

.cta-content p {
    font-size: 20px;
    margin-bottom: 32px;
    opacity: 0.9;
}

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

.cta-section .btn-primary:hover {
    background: var(--bg-gray);
    transform: translateY(-2px);
}

/* Footer */
.footer {
    background: var(--text-dark);
    color: white;
    padding: 64px 0 32px;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 64px;
    margin-bottom: 48px;
}

.footer-brand h3 {
    font-size: 24px;
    margin-bottom: 12px;
    color: var(--primary-light);
}

.footer-brand p {
    color: var(--text-light);
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 32px;
}

.footer-column h4 {
    font-size: 18px;
    margin-bottom: 16px;
    color: white;
}

.footer-column ul {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-column a {
    color: var(--text-light);
}

.footer-column a:hover {
    color: var(--primary-light);
}

.footer-bottom {
    padding-top: 32px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    color: var(--text-light);
}

/* Legal Pages */
.legal-content {
    max-width: 800px;
    margin: 0 auto;
}

.legal-intro {
    margin-bottom: 48px;
    padding: 32px;
    background: var(--primary-bg);
    border-radius: var(--radius-lg);
    border-left: 4px solid var(--primary-color);
}

.legal-section {
    margin-bottom: 48px;
}

.legal-section h2 {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 16px;
}

.legal-section h3 {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-dark);
    margin-top: 24px;
    margin-bottom: 12px;
}

.legal-section p {
    font-size: 16px;
    line-height: 1.8;
    color: var(--text-gray);
    margin-bottom: 16px;
}

.legal-section ul {
    margin: 16px 0;
    padding-left: 24px;
    list-style: disc;
}

.legal-section li {
    margin-bottom: 8px;
    color: var(--text-gray);
    line-height: 1.6;
}

.legal-section a {
    color: var(--primary-color);
}

.legal-section a:hover {
    text-decoration: underline;
}

.legal-footer {
    margin-top: 64px;
    padding-top: 32px;
    border-top: 2px solid var(--border-color);
    text-align: center;
    color: var(--text-gray);
}

/* Contact Page */
.contact-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 64px;
}

.contact-form-wrapper {
    background: var(--bg-white);
    padding: 48px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.contact-form-header {
    margin-bottom: 32px;
}

.contact-form-header h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-dark);
}

.contact-form-header p {
    color: var(--text-gray);
}

.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-dark);
}

.required {
    color: #EF4444;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 16px;
    font-family: inherit;
    transition: var(--transition);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px var(--primary-bg);
}

.checkbox-label {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
    width: auto;
    margin-top: 4px;
    cursor: pointer;
}

.checkbox-label a {
    color: var(--primary-color);
}

.checkbox-label a:hover {
    text-decoration: underline;
}

.form-message {
    margin-top: 16px;
    padding: 12px 16px;
    border-radius: var(--radius-md);
    display: none;
}

.form-message.success {
    background: #D1FAE5;
    color: #065F46;
    border: 1px solid #10B981;
    display: block;
}

.form-message.error {
    background: #FEE2E2;
    color: #991B1B;
    border: 1px solid #EF4444;
    display: block;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.contact-info-card {
    background: var(--bg-white);
    padding: 32px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.contact-info-card h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text-dark);
}

.contact-item {
    display: flex;
    gap: 16px;
    margin-bottom: 32px;
}

.contact-item:last-child {
    margin-bottom: 0;
}

.contact-icon {
    width: 48px;
    height: 48px;
    background: var(--primary-bg);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    flex-shrink: 0;
}

.contact-item h4 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-dark);
}

.contact-item p {
    color: var(--text-gray);
    margin-bottom: 4px;
}

.contact-item a {
    color: var(--primary-color);
}

.contact-item a:hover {
    text-decoration: underline;
}

.text-muted {
    color: var(--text-light);
    font-size: 14px;
}

.support-list,
.faq-links {
    list-style: disc;
    padding-left: 24px;
    margin-top: 12px;
}

.support-list li,
.faq-links li {
    margin-bottom: 8px;
    color: var(--text-gray);
    line-height: 1.6;
}

.faq-links a {
    color: var(--primary-color);
}

.faq-links a:hover {
    text-decoration: underline;
}

/* Download Page */
.download-content {
    display: flex;
    flex-direction: column;
    gap: 64px;
}

.download-main {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.download-buttons {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.download-btn {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px 24px;
    border-radius: var(--radius-md);
    background: var(--text-dark);
    color: white;
    transition: var(--transition);
    border: none;
    cursor: pointer;
}

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

.download-btn-apple {
    background: #000000;
}

.download-btn-google {
    background: #000000;
}

.download-btn-label {
    display: block;
    font-size: 12px;
    opacity: 0.8;
}

.download-btn-platform {
    display: block;
    font-size: 20px;
    font-weight: 600;
}

.download-image img {
    width: 100%;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
}

.download-info {
    margin-top: 32px;
}

.info-card {
    background: var(--bg-white);
    padding: 32px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.info-card h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 24px;
    color: var(--text-dark);
}

.requirements {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
}

.requirement-item h4 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.requirement-item ul {
    list-style: disc;
    padding-left: 24px;
}

.requirement-item li {
    margin-bottom: 8px;
    color: var(--text-gray);
    line-height: 1.6;
}

/* Steps */
.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
}

.step-item {
    display: flex;
    gap: 24px;
}

.step-number {
    width: 48px;
    height: 48px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 700;
    flex-shrink: 0;
}

.step-content h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-dark);
}

.step-content p {
    color: var(--text-gray);
    line-height: 1.6;
}

/* Features Reminder */
.features-reminder {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 32px;
}

.feature-reminder-item {
    text-align: center;
    padding: 32px;
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.feature-reminder-item svg {
    color: var(--primary-color);
    margin: 0 auto 16px;
}

.feature-reminder-item h4 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-dark);
}

.feature-reminder-item p {
    color: var(--text-gray);
    font-size: 14px;
}

/* Help Section */
.help-section {
    text-align: center;
    padding: 48px;
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

.help-section h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-dark);
}

.help-section p {
    font-size: 18px;
    color: var(--text-gray);
    margin-bottom: 32px;
}

/* Values Grid */
.values-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
}

.value-card {
    background: var(--bg-white);
    padding: 32px;
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.value-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.value-icon {
    width: 64px;
    height: 64px;
    background: var(--primary-bg);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    margin: 0 auto 24px;
}

.value-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--text-dark);
}

.value-card p {
    color: var(--text-gray);
    line-height: 1.6;
}

/* Timeline */
.timeline {
    position: relative;
    padding-left: 32px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 8px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border-color);
}

.timeline-item {
    position: relative;
    margin-bottom: 48px;
    padding-left: 48px;
}

.timeline-marker {
    position: absolute;
    left: -24px;
    top: 0;
    width: 16px;
    height: 16px;
    background: var(--primary-color);
    border-radius: 50%;
    border: 4px solid var(--bg-white);
    box-shadow: 0 0 0 2px var(--primary-color);
}

.timeline-content h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-dark);
}

.timeline-date {
    font-size: 14px;
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 12px;
}

.timeline-content p {
    color: var(--text-gray);
    line-height: 1.6;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .hero-split .hero-content,
    .content-split,
    .download-main,
    .contact-content {
        grid-template-columns: 1fr;
    }

    .content-split-reverse {
        direction: ltr;
    }

    .use-case-item {
        grid-template-columns: 1fr;
    }

    .use-case-reverse {
        direction: ltr;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: var(--bg-white);
        flex-direction: column;
        padding: 32px;
        box-shadow: var(--shadow-lg);
        transform: translateX(-100%);
        transition: var(--transition);
        z-index: 999;
    }

    .nav-menu.active {
        transform: translateX(0);
    }

    .nav-toggle {
        display: flex;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 22px;
    }

    .section-title {
        font-size: 32px;
    }

    .page-header h1 {
        font-size: 36px;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .contact-form-wrapper {
        padding: 32px 24px;
    }

    .container {
        padding: 0 16px;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 80px 0 60px;
    }

    .section {
        padding: 60px 0;
    }

    .hero-title {
        font-size: 28px;
    }

    .hero-subtitle {
        font-size: 18px;
    }

    .section-title {
        font-size: 28px;
    }

    .btn-large {
        padding: 14px 24px;
        font-size: 16px;
    }
}