/* ===================================
   CSS Variables & Base Styles
   =================================== */
:root {
    /* Colors - Coral/Teal Theme to match 小犀助手 screenshots */
    --primary: #E87878;
    --primary-light: #F09090;
    --primary-dark: #D05858;
    --accent: #3EBEBB;
    --accent-light: #5DCFCC;
    --gradient: linear-gradient(135deg, #F8D7D7 0%, #E8F4F8 100%);
    --gradient-primary: linear-gradient(135deg, #E87878 0%, #F09090 100%);

    --text-primary: #1F2937;
    --text-secondary: #6B7280;
    --text-light: #9CA3AF;

    --bg-primary: #FFFFFF;
    --bg-secondary: #FDF8F8;
    --bg-tertiary: #F8E8E8;
    --bg-teal: #E8F4F4;

    --border: #F3E0E0;

    /* Spacing */
    --section-padding: 120px;
    --container-width: 1200px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Shadows */
    --shadow-sm: 0 1px 2px 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);
    --shadow-phone: 0 25px 50px -12px rgba(0, 0, 0, 0.15);

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-phone: 32px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--text-primary);
    background: var(--bg-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 24px;
}

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

a {
    text-decoration: none;
    color: inherit;
}

/* ===================================
   Navigation
   =================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid transparent;
    transition: var(--transition-normal);
}

.navbar.scrolled {
    border-bottom-color: var(--border);
}

.nav-container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 600;
    font-size: 18px;
    color: var(--text-primary);
}

.logo-image {
    height: 36px;
    width: auto;
    object-fit: contain;
    border-radius: 8px;
}

div.nav-logo {
    cursor: default;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-links a {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: var(--transition-fast);
}

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

.nav-cta {
    padding: 10px 20px;
    background: var(--gradient-primary);
    color: white !important;
    border-radius: var(--radius-sm);
    font-weight: 500;
    border: none;
}

.nav-cta:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

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

.mobile-menu {
    display: none;
    position: fixed;
    top: 65px;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    padding: 24px;
    flex-direction: column;
    gap: 16px;
    border-bottom: 1px solid var(--border);
    z-index: 999;
}

.mobile-menu.active {
    display: flex;
}

.mobile-menu a {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-secondary);
    padding: 12px 0;
}

.mobile-cta {
    text-align: center;
    padding: 14px 24px !important;
    background: var(--gradient-primary);
    color: white !important;
    border-radius: var(--radius-sm);
    border: none;
}

/* ===================================
   Buttons
   =================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    font-size: 16px;
    font-weight: 500;
    border-radius: var(--radius-sm);
    transition: var(--transition-normal);
    cursor: pointer;
    border: none;
}

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

.btn-primary:hover {
    opacity: 0.9;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

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

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

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

.btn-large {
    padding: 18px 36px;
    font-size: 17px;
}

/* ===================================
   Hero Section
   =================================== */
.hero {
    min-height: 100vh;
    padding: 140px 24px 80px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    background: linear-gradient(180deg, #FDF5F5 0%, #F0F8F8 50%, #FFFFFF 100%);
    overflow: hidden;
}

.hero-content {
    max-width: 800px;
    margin-bottom: 60px;
}

.hero-title {
    font-size: clamp(40px, 8vw, 64px);
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 24px;
    background: linear-gradient(135deg, #E87878 0%, #3EBEBB 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(18px, 3vw, 22px);
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 40px;
}

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

.hero-image {
    width: 100%;
    max-width: 400px;
    position: relative;
}

/* Phone showcase for hero */
.phone-showcase {
    position: relative;
    display: flex;
    justify-content: center;
}

.phone-frame-hero {
    width: 280px;
    background: #475569;
    border-radius: var(--radius-phone);
    padding: 12px;
    box-shadow: var(--shadow-phone);
}

.phone-frame-hero img {
    border-radius: calc(var(--radius-phone) - 8px);
    width: 100%;
}

/* ===================================
   Features Overview
   =================================== */
.features {
    padding: var(--section-padding) 0;
    background: var(--bg-primary);
}

.section-title {
    font-size: clamp(32px, 5vw, 48px);
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
}

.section-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    text-align: center;
    max-width: 600px;
    margin: 0 auto 60px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.feature-card {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 40px 32px;
    text-align: center;
    transition: var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    width: 72px;
    height: 72px;
    margin: 0 auto 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}

.feature-icon.fee-icon {
    background: linear-gradient(135deg, rgba(232, 120, 120, 0.15) 0%, rgba(240, 144, 144, 0.15) 100%);
}

.feature-icon.interest-icon {
    background: linear-gradient(135deg, rgba(62, 190, 187, 0.15) 0%, rgba(93, 207, 204, 0.15) 100%);
}

.feature-icon.date-icon {
    background: linear-gradient(135deg, rgba(232, 120, 120, 0.15) 0%, rgba(62, 190, 187, 0.15) 100%);
}

.feature-icon svg {
    width: 40px;
    height: 40px;
    color: var(--primary);
}

.feature-icon.interest-icon svg {
    color: var(--accent);
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
}

.feature-card p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ===================================
   Feature Detail Sections
   =================================== */
.feature-detail {
    padding: var(--section-padding) 0;
    background: var(--bg-primary);
}

.feature-detail.alt {
    background: linear-gradient(180deg, #F8FCFC 0%, #FFFFFF 100%);
}

.detail-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

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

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

.feature-tag {
    display: inline-block;
    padding: 8px 16px;
    background: linear-gradient(135deg, rgba(232, 120, 120, 0.15) 0%, rgba(62, 190, 187, 0.15) 100%);
    color: var(--primary);
    font-size: 14px;
    font-weight: 500;
    border-radius: 20px;
    margin-bottom: 20px;
}

.detail-text h2 {
    font-size: clamp(28px, 4vw, 40px);
    font-weight: 700;
    margin-bottom: 20px;
}

.feature-desc {
    font-size: 18px;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 32px;
}

.feature-list {
    list-style: none;
}

.feature-list li {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 0;
    font-size: 16px;
    color: var(--text-primary);
}

.feature-list svg {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
    color: var(--accent);
}

/* ===================================
   Screenshot Layouts
   =================================== */

/* Stack of 3 screenshots (fee section) */
.screenshots-stack-3 {
    position: relative;
    height: 520px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.screenshots-stack-3 .screenshot-item {
    position: absolute;
    width: 220px;
    border-radius: var(--radius-phone);
    overflow: hidden;
    box-shadow: var(--shadow-phone);
    background: #475569;
    padding: 8px;
    transition: var(--transition-normal);
}

.screenshots-stack-3 .screenshot-item img {
    border-radius: calc(var(--radius-phone) - 4px);
    width: 100%;
}

.screenshots-stack-3 .screenshot-back-2 {
    transform: translateX(-80px) rotate(-8deg) scale(0.9);
    z-index: 1;
    opacity: 0.7;
}

.screenshots-stack-3 .screenshot-back-1 {
    transform: translateX(80px) rotate(8deg) scale(0.9);
    z-index: 2;
    opacity: 0.85;
}

.screenshots-stack-3 .screenshot-front {
    transform: translateX(0) rotate(0deg) scale(1);
    z-index: 3;
}

.screenshots-stack-3:hover .screenshot-back-2 {
    transform: translateX(-100px) rotate(-10deg) scale(0.88);
}

.screenshots-stack-3:hover .screenshot-back-1 {
    transform: translateX(100px) rotate(10deg) scale(0.88);
}

/* Stack of 4 screenshots (interest section) */
.screenshots-stack-4 {
    position: relative;
    height: 560px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.screenshots-stack-4 .screenshot-item {
    position: absolute;
    width: 200px;
    border-radius: var(--radius-phone);
    overflow: hidden;
    box-shadow: var(--shadow-phone);
    background: #475569;
    padding: 8px;
    transition: var(--transition-normal);
}

.screenshots-stack-4 .screenshot-item img {
    border-radius: calc(var(--radius-phone) - 4px);
    width: 100%;
}

.screenshots-stack-4 .screenshot-pos-1 {
    transform: translateX(-120px) translateY(-30px) rotate(-12deg) scale(0.85);
    z-index: 1;
    opacity: 0.6;
}

.screenshots-stack-4 .screenshot-pos-2 {
    transform: translateX(-40px) translateY(30px) rotate(-4deg) scale(0.92);
    z-index: 2;
    opacity: 0.8;
}

.screenshots-stack-4 .screenshot-pos-3 {
    transform: translateX(40px) translateY(-30px) rotate(4deg) scale(0.92);
    z-index: 3;
    opacity: 0.9;
}

.screenshots-stack-4 .screenshot-pos-4 {
    transform: translateX(100px) translateY(20px) rotate(8deg) scale(1);
    z-index: 4;
}

.screenshots-stack-4:hover .screenshot-pos-1 {
    transform: translateX(-140px) translateY(-40px) rotate(-14deg) scale(0.83);
}

.screenshots-stack-4:hover .screenshot-pos-4 {
    transform: translateX(120px) translateY(30px) rotate(10deg) scale(1.02);
}

/* Side by side 2 screenshots (date section) */
.screenshots-stack-2 {
    position: relative;
    height: 480px;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
}

.screenshots-stack-2 .screenshot-item {
    width: 200px;
    border-radius: var(--radius-phone);
    overflow: hidden;
    box-shadow: var(--shadow-phone);
    background: #475569;
    padding: 8px;
    transition: var(--transition-normal);
}

.screenshots-stack-2 .screenshot-item img {
    border-radius: calc(var(--radius-phone) - 4px);
    width: 100%;
}

.screenshots-stack-2 .screenshot-left {
    transform: rotate(-5deg) translateY(20px);
}

.screenshots-stack-2 .screenshot-right {
    transform: rotate(5deg) translateY(-20px);
}

.screenshots-stack-2:hover .screenshot-left {
    transform: rotate(-8deg) translateY(30px) scale(1.02);
}

.screenshots-stack-2:hover .screenshot-right {
    transform: rotate(8deg) translateY(-30px) scale(1.02);
}

/* ===================================
   CTA Section
   =================================== */
.cta-section {
    padding: var(--section-padding) 0;
    background: linear-gradient(135deg, #E87878 0%, #3EBEBB 100%);
}

.cta-content {
    text-align: center;
    color: white;
}

.cta-content h2 {
    font-size: clamp(32px, 5vw, 48px);
    font-weight: 700;
    margin-bottom: 16px;
}

.cta-content p {
    font-size: 18px;
    opacity: 0.9;
    margin-bottom: 40px;
}

.cta-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

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

.cta-section .btn-outline {
    border-color: white;
    color: white;
}

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

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

.footer-content {
    display: flex;
    justify-content: space-between;
    gap: 60px;
    padding-bottom: 60px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 16px;
}

.footer-logo .logo-icon {
    color: white;
}

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

.footer-links {
    display: flex;
    gap: 80px;
}

.footer-column h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.footer-column a {
    display: block;
    font-size: 14px;
    color: var(--text-light);
    padding: 8px 0;
    transition: var(--transition-fast);
}

.footer-column a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
}

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

/* ===================================
   Animations
   =================================== */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    animation: fadeIn 0.8s ease forwards;
}

.delay-1 {
    animation-delay: 0.2s;
}

.delay-2 {
    animation-delay: 0.4s;
}

.delay-3 {
    animation-delay: 0.6s;
}

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

.scroll-reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.scroll-reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

.scroll-reveal.delay-1 {
    transition-delay: 0.1s;
}

.scroll-reveal.delay-2 {
    transition-delay: 0.2s;
}

.scroll-reveal.delay-3 {
    transition-delay: 0.3s;
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 1024px) {
    :root {
        --section-padding: 80px;
    }

    .features-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 24px;
    }

    .detail-content {
        gap: 60px;
    }

    .screenshots-stack-3 .screenshot-item {
        width: 180px;
    }

    .screenshots-stack-4 .screenshot-item {
        width: 160px;
    }

    .screenshots-stack-2 .screenshot-item {
        width: 170px;
    }
}

@media (max-width: 768px) {
    :root {
        --section-padding: 60px;
    }

    .nav-links {
        display: none;
    }

    .nav-toggle {
        display: flex;
    }

    .hero {
        padding: 120px 24px 60px;
    }

    .hero-content {
        margin-bottom: 40px;
    }

    .phone-frame-hero {
        width: 240px;
    }

    .features-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .feature-card {
        padding: 32px 24px;
    }

    .detail-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

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

    .detail-image {
        order: -1;
    }

    /* Mobile screenshot layouts */
    .screenshots-stack-3 {
        height: 420px;
    }

    .screenshots-stack-3 .screenshot-item {
        width: 160px;
    }

    .screenshots-stack-3 .screenshot-back-2 {
        transform: translateX(-50px) rotate(-6deg) scale(0.88);
    }

    .screenshots-stack-3 .screenshot-back-1 {
        transform: translateX(50px) rotate(6deg) scale(0.88);
    }

    .screenshots-stack-4 {
        height: 450px;
    }

    .screenshots-stack-4 .screenshot-item {
        width: 140px;
    }

    .screenshots-stack-4 .screenshot-pos-1 {
        transform: translateX(-90px) translateY(-20px) rotate(-10deg) scale(0.8);
    }

    .screenshots-stack-4 .screenshot-pos-2 {
        transform: translateX(-30px) translateY(20px) rotate(-3deg) scale(0.88);
    }

    .screenshots-stack-4 .screenshot-pos-3 {
        transform: translateX(30px) translateY(-20px) rotate(3deg) scale(0.88);
    }

    .screenshots-stack-4 .screenshot-pos-4 {
        transform: translateX(80px) translateY(15px) rotate(6deg) scale(0.95);
    }

    .screenshots-stack-2 {
        height: 400px;
        gap: 10px;
    }

    .screenshots-stack-2 .screenshot-item {
        width: 150px;
    }

    .footer-content {
        flex-direction: column;
        gap: 40px;
    }

    .footer-links {
        gap: 40px;
    }
}

@media (max-width: 480px) {
    .hero-cta {
        flex-direction: column;
        width: 100%;
    }

    .hero-cta .btn {
        width: 100%;
    }

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

    .cta-buttons .btn {
        width: 100%;
    }

    .screenshots-stack-3 {
        height: 380px;
    }

    .screenshots-stack-3 .screenshot-item {
        width: 140px;
    }

    .screenshots-stack-4 {
        height: 400px;
    }

    .screenshots-stack-4 .screenshot-item {
        width: 120px;
    }

    .screenshots-stack-2 .screenshot-item {
        width: 130px;
    }
}

/* ===================================
   QR Code Modal
   =================================== */
.qr-modal {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.qr-modal.active {
    opacity: 1;
    visibility: visible;
}

.qr-modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

.qr-modal-content {
    position: relative;
    background: white;
    border-radius: var(--radius-xl);
    padding: 48px;
    max-width: 400px;
    width: 100%;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    transform: scale(0.9) translateY(20px);
    transition: transform 0.3s ease;
}

.qr-modal.active .qr-modal-content {
    transform: scale(1) translateY(0);
}

.qr-modal-close {
    position: absolute;
    top: 16px;
    right: 16px;
    width: 40px;
    height: 40px;
    border: none;
    background: var(--bg-tertiary);
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
}

.qr-modal-close:hover {
    background: var(--border);
    transform: rotate(90deg);
}

.qr-modal-close svg {
    width: 20px;
    height: 20px;
    color: var(--text-secondary);
}

.qr-modal-body {
    text-align: center;
}

.qr-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 20px;
    color: var(--primary);
}

.qr-icon svg {
    width: 100%;
    height: 100%;
}

.qr-modal-body h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 8px;
    background: linear-gradient(135deg, #E87878 0%, #3EBEBB 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.qr-modal-body>p {
    font-size: 15px;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.qr-image {
    width: 220px;
    height: 220px;
    margin: 0 auto 24px;
    padding: 12px;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    border: 2px solid var(--border);
    overflow: hidden;
}

.qr-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: var(--radius-sm);
}

.qr-tips {
    display: flex;
    justify-content: center;
    gap: 24px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
}

.qr-tips span {
    font-size: 14px;
    color: var(--text-secondary);
}

/* Button reset for nav-cta */
button.nav-cta,
button.mobile-cta {
    font-family: inherit;
    cursor: pointer;
}

@media (max-width: 480px) {
    .qr-modal-content {
        padding: 32px 24px;
    }

    .qr-image {
        width: 180px;
        height: 180px;
    }

    .qr-tips {
        flex-direction: column;
        gap: 8px;
    }
}