/* ========================================
   无忧水印 - 像素风格样式表
   ======================================== */

/* Import Pixel Font */
@import url('https://fonts.googleapis.com/css2?family=Press+Start+2P&family=Noto+Sans+SC:wght@400;500;700&display=swap');

/* ========================================
   CSS Variables - Design System
   ======================================== */
:root {
    /* Colors */
    --color-primary: #FF6B6B;
    --color-primary-dark: #EE5A52;
    --color-secondary: #4ECDC4;
    --color-accent: #FFE66D;
    --color-success: #51CF66;
    --color-background: #FAFAFA;
    --color-surface: #FFFFFF;
    --color-text: #2C3E50;
    --color-text-light: #7F8C8D;
    --color-border: #E0E0E0;
    --color-shadow: rgba(0, 0, 0, 0.1);

    /* Pixel Shadows */
    --shadow-pixel:
        4px 0 0 var(--color-border),
        -4px 0 0 var(--color-border),
        0 4px 0 var(--color-border),
        0 -4px 0 var(--color-border);

    --shadow-pixel-large:
        6px 0 0 var(--color-border),
        -6px 0 0 var(--color-border),
        0 6px 0 var(--color-border),
        0 -6px 0 var(--color-border),
        6px 6px 0 var(--color-border),
        -6px -6px 0 var(--color-border),
        6px -6px 0 var(--color-border),
        -6px 6px 0 var(--color-border);

    /* Spacing */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    --spacing-2xl: 64px;

    /* Typography */
    --font-pixel: 'Press Start 2P', cursive;
    --font-main: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-main);
    color: var(--color-text);
    background-color: var(--color-background);
    line-height: 1.6;
    -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-fast);
}

ul {
    list-style: none;
}

/* ========================================
   Layout Utilities
   ======================================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.container-narrow {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.section {
    padding: var(--spacing-2xl) 0;
}

/* ========================================
   Typography
   ======================================== */
.pixel-text {
    font-family: var(--font-pixel);
    line-height: 1.6;
    letter-spacing: 2px;
    image-rendering: pixelated;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

/* ========================================
   Header & Navigation
   ======================================== */
.header {
    background: var(--color-surface);
    border-bottom: 4px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 4px 12px var(--color-shadow);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.nav-logo {
    width: 40px;
    height: 40px;
    border: 3px solid var(--color-border);
    border-radius: var(--radius-sm);
    image-rendering: pixelated;
}

.nav-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.nav-link {
    font-weight: 500;
    color: var(--color-text-light);
    transition: var(--transition-fast);
    position: relative;
}

.nav-link:hover {
    color: var(--color-primary);
}

.nav-link.active {
    color: var(--color-primary);
    font-weight: 700;
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--color-primary);
}

/* ========================================
   Buttons
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 12px 24px;
    font-weight: 700;
    font-size: 0.95rem;
    border: 3px solid var(--color-text);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    text-align: center;
    white-space: nowrap;
}

.btn::before {
    content: '';
    position: absolute;
    top: 4px;
    left: 4px;
    width: 100%;
    height: 100%;
    background: var(--color-text);
    border-radius: var(--radius-sm);
    z-index: -1;
    transition: var(--transition-fast);
}

.btn:hover {
    transform: translate(2px, 2px);
}

.btn:hover::before {
    transform: translate(-2px, -2px);
}

.btn:active {
    transform: translate(4px, 4px);
}

.btn:active::before {
    transform: translate(0, 0);
}

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

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

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

.btn-secondary::before {
    background: var(--color-border);
}

.btn-small {
    padding: 8px 16px;
    font-size: 0.875rem;
}

.btn-large {
    padding: 16px 32px;
    font-size: 1.1rem;
}

.btn-glow {
    animation: pulse-glow 2s ease-in-out infinite;
}

@keyframes pulse-glow {
    0%, 100% {
        box-shadow: 0 0 0 0 rgba(255, 107, 107, 0.4);
    }
    50% {
        box-shadow: 0 0 0 12px rgba(255, 107, 107, 0);
    }
}

.btn-icon {
    font-size: 1.2em;
}

/* ========================================
   Badge
   ======================================== */
.badge {
    display: inline-block;
    padding: 6px 12px;
    background: var(--color-accent);
    color: var(--color-text);
    font-weight: 700;
    font-size: 0.875rem;
    border: 3px solid var(--color-text);
    border-radius: var(--radius-sm);
    margin-bottom: var(--spacing-sm);
}

.section-badge {
    display: inline-block;
    padding: 8px 16px;
    background: var(--color-secondary);
    color: white;
    font-weight: 700;
    font-size: 0.95rem;
    border: 3px solid var(--color-text);
    border-radius: var(--radius-sm);
    margin-bottom: var(--spacing-md);
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    padding: var(--spacing-2xl) 0;
    background: linear-gradient(135deg, #FFE6E6 0%, #E6F9F7 100%);
    border-bottom: 4px solid var(--color-border);
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.hero-text {
    animation: fadeInLeft 0.8s ease;
}

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.hero-title {
    font-size: 3.5rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
}

.hero-description {
    font-size: 1.1rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.hero-stats {
    display: flex;
    gap: var(--spacing-lg);
}

.stat-item {
    text-align: center;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin-top: 4px;
}

.hero-image {
    display: flex;
    justify-content: center;
    animation: fadeInRight 0.8s ease;
}

@keyframes fadeInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.phone-mockup {
    position: relative;
    width: 100%;
    max-width: 350px;
    padding: 16px;
    background: white;
    border: 4px solid var(--color-text);
    border-radius: var(--radius-lg);
    box-shadow:
        8px 8px 0 var(--color-border),
        16px 16px 0 var(--color-text);
}

.screenshot {
    width: 100%;
    border-radius: var(--radius-md);
    border: 3px solid var(--color-border);
}

/* ========================================
   Section Styles
   ======================================== */
.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.section-title {
    font-size: 2.5rem;
    color: var(--color-text);
}

.section-subtitle {
    font-size: 1.2rem;
    color: var(--color-text-light);
}

.section-highlight {
    background: var(--color-surface);
    border-top: 4px solid var(--color-border);
    border-bottom: 4px solid var(--color-border);
}

/* ========================================
   Privacy Section
   ======================================== */
.privacy-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
}

.privacy-card {
    padding: var(--spacing-lg);
    background: var(--color-background);
    border: 4px solid var(--color-text);
    border-radius: var(--radius-md);
    text-align: center;
    transition: var(--transition-normal);
    position: relative;
}

.privacy-card::before {
    content: '';
    position: absolute;
    top: 8px;
    left: 8px;
    width: 100%;
    height: 100%;
    background: var(--color-text);
    border-radius: var(--radius-md);
    z-index: -1;
    transition: var(--transition-fast);
}

.privacy-card:hover {
    transform: translate(4px, 4px);
}

.privacy-card:hover::before {
    transform: translate(-4px, -4px);
}

.privacy-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.privacy-title {
    font-size: 1.3rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.privacy-description {
    color: var(--color-text-light);
    line-height: 1.6;
}

/* ========================================
   Features Section
   ======================================== */
.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.feature-card {
    padding: var(--spacing-md);
    background: var(--color-surface);
    border: 3px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: var(--transition-normal);
}

.feature-card:hover {
    border-color: var(--color-primary);
    transform: translateY(-4px);
    box-shadow: 0 8px 16px var(--color-shadow);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
}

.feature-title {
    font-size: 1.2rem;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
}

.feature-description {
    font-size: 0.95rem;
    color: var(--color-text-light);
    line-height: 1.6;
}

/* ========================================
   Use Cases Section
   ======================================== */
.usecases-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-md);
}

.usecase-item {
    padding: var(--spacing-md);
    background: var(--color-background);
    border: 3px solid var(--color-border);
    border-radius: var(--radius-md);
    text-align: center;
    transition: var(--transition-fast);
}

.usecase-item:hover {
    background: var(--color-accent);
    border-color: var(--color-text);
}

.usecase-icon {
    font-size: 2rem;
    margin-bottom: var(--spacing-xs);
}

.usecase-title {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 4px;
}

.usecase-text {
    font-size: 0.9rem;
    color: var(--color-text-light);
}

/* ========================================
   CTA Section
   ======================================== */
.section-cta {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    color: white;
    text-align: center;
    border-top: 4px solid var(--color-text);
    border-bottom: 4px solid var(--color-text);
}

.cta-content {
    max-width: 700px;
    margin: 0 auto;
}

.cta-title {
    font-size: 2.5rem;
    color: white;
    margin-bottom: var(--spacing-sm);
}

.cta-subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-lg);
}

.cta-notes {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
    flex-wrap: wrap;
}

.cta-note {
    font-size: 0.95rem;
    color: rgba(255, 255, 255, 0.8);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--color-text);
    color: white;
    padding: var(--spacing-xl) 0 var(--spacing-md);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr repeat(3, 1fr);
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

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

.footer-logo {
    width: 60px;
    height: 60px;
    border: 3px solid white;
    border-radius: var(--radius-sm);
}

.footer-tagline {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.6;
}

.footer-title {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-sm);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.footer-link {
    color: rgba(255, 255, 255, 0.7);
    transition: var(--transition-fast);
}

.footer-link:hover {
    color: var(--color-accent);
    padding-left: 4px;
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-md);
    border-top: 2px solid rgba(255, 255, 255, 0.2);
}

.footer-copyright {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
    margin-bottom: 4px;
}

.footer-note {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.85rem;
}

/* ========================================
   Privacy Policy Page
   ======================================== */
.policy-section {
    padding: var(--spacing-xl) 0;
}

.policy-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 3px solid var(--color-border);
}

.policy-title {
    font-size: 3rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.policy-meta {
    color: var(--color-text-light);
    font-size: 0.95rem;
    margin-bottom: var(--spacing-md);
}

.policy-highlight {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-accent);
    border: 3px solid var(--color-text);
    border-radius: var(--radius-md);
    font-weight: 500;
    margin-top: var(--spacing-sm);
}

.policy-content {
    line-height: 1.8;
}

.policy-section-item {
    margin-bottom: var(--spacing-xl);
}

.policy-subtitle {
    font-size: 1.8rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-xs);
    border-bottom: 3px solid var(--color-border);
}

.policy-list {
    margin-left: var(--spacing-md);
    margin-top: var(--spacing-sm);
}

.policy-list li {
    margin-bottom: var(--spacing-sm);
    padding-left: var(--spacing-sm);
    position: relative;
}

.policy-list li::before {
    content: '▶';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-size: 0.8em;
}

.permission-item {
    padding: var(--spacing-md);
    background: var(--color-background);
    border: 3px solid var(--color-border);
    border-radius: var(--radius-md);
    margin-top: var(--spacing-md);
}

.permission-title {
    font-size: 1.2rem;
    color: var(--color-secondary);
    margin-bottom: var(--spacing-sm);
}

.policy-footer {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 3px solid var(--color-border);
}

.policy-promise {
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    color: white;
    border: 4px solid var(--color-text);
    border-radius: var(--radius-md);
    text-align: center;
}

.policy-promise h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 1024px) {
    .hero-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .hero-image {
        order: -1;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

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

@media (max-width: 768px) {
    .nav-menu {
        gap: var(--spacing-sm);
    }

    .nav-link {
        font-size: 0.9rem;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .hero-buttons {
        flex-direction: column;
    }

    .hero-stats {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

    .section-title {
        font-size: 1.8rem;
    }

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

    .usecases-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .cta-title {
        font-size: 1.8rem;
    }
}

@media (max-width: 480px) {
    :root {
        font-size: 14px;
    }

    .nav-title {
        font-size: 1rem;
    }

    .nav-logo {
        width: 32px;
        height: 32px;
    }

    .hero-title {
        font-size: 1.5rem;
    }

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

    .btn-large {
        padding: 14px 24px;
        font-size: 1rem;
    }
}

/* ========================================
   Animations & Interactions
   ======================================== */
@keyframes float {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

.phone-mockup {
    animation: float 3s ease-in-out infinite;
}

/* Smooth scroll offset for fixed header */
html {
    scroll-padding-top: 80px;
}

/* Selection styling */
::selection {
    background: var(--color-accent);
    color: var(--color-text);
}

/* Focus styles */
*:focus {
    outline: 3px solid var(--color-primary);
    outline-offset: 2px;
}

/* Loading state */
.loading {
    opacity: 0.6;
    pointer-events: none;
}