:root {
    --bg-color: #0f172a;
    --primary-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
    --text-color: #f8fafc;
    --secondary-text: #94a3b8;
    --card-bg: rgba(30, 41, 59, 0.4);
    --border-color: rgba(255, 255, 255, 0.1);
    --hover-color: rgba(99, 102, 241, 0.3);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
}

/* Utilities */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 50px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: var(--primary-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.6);
}

h1, h2, h3 {
    line-height: 1.2;
}

/* Navbar */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    padding: 20px 0;
    backdrop-filter: blur(10px);
    background: rgba(15, 23, 42, 0.8);
    border-bottom: 1px solid var(--border-color);
}

nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 24px;
    font-weight: 800;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    display: flex;
    gap: 30px;
    align-items: center;
}

.nav-links a {
    color: var(--text-color);
    text-decoration: none;
    font-size: 15px;
    opacity: 0.8;
    transition: opacity 0.3s;
}

.nav-links a:hover {
    opacity: 1;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    padding-top: 80px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    width: 600px;
    height: 600px;
    background: var(--primary-gradient);
    filter: blur(120px);
    opacity: 0.15;
    border-radius: 50%;
    z-index: -1;
    animation: pulse 8s infinite alternate;
}

@keyframes pulse {
    0% { transform: scale(1); opacity: 0.15; }
    100% { transform: scale(1.1); opacity: 0.25; }
}

.hero h1 {
    font-size: 4rem;
    font-weight: 800;
    margin-bottom: 24px;
    background: linear-gradient(to right, #fff, #cbd5e1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.25rem;
    color: var(--secondary-text);
    max-width: 600px;
    margin: 0 auto 40px;
}

/* Features Section */
.features {
    padding: 100px 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 60px;
    font-weight: 700;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--card-bg);
    padding: 40px 30px;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    transition: transform 0.3s, border-color 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: rgba(168, 85, 247, 0.5);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
    display: inline-block;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 12px;
    color: #fff;
}

.feature-card p {
    color: var(--secondary-text);
    font-size: 0.95rem;
}

/* Scenarios Section */
.scenarios {
    padding: 100px 0;
    background: linear-gradient(to bottom, var(--bg-color), #020617);
}

.scenario-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 100px;
    gap: 60px;
}

.scenario-item:nth-child(even) {
    flex-direction: row-reverse;
}

.scenario-text {
    flex: 1;
}

.scenario-text h3 {
    font-size: 2rem;
    margin-bottom: 20px;
    color: #fff;
}

.scenario-text p {
    font-size: 1.1rem;
    color: var(--secondary-text);
    margin-bottom: 30px;
}

.scenario-visual {
    flex: 1;
    background: rgba(30, 41, 59, 0.3);
    border-radius: 24px;
    padding: 40px;
    border: 1px solid var(--border-color);
    position: relative;
    box-shadow: 0 20px 40px rgba(0,0,0,0.2);
}

/* Chat UI Simulation */
.chat-message {
    margin-bottom: 20px;
    max-width: 85%;
    padding: 15px 20px;
    border-radius: 18px;
    font-size: 0.95rem;
    line-height: 1.5;
    position: relative;
}

.chat-user {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    margin-left: auto;
    border-bottom-right-radius: 4px;
}

.chat-ai {
    background: rgba(99, 102, 241, 0.2);
    color: #e0e7ff;
    border-top-left-radius: 4px;
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.chat-ai::before {
    content: '🤖';
    position: absolute;
    top: -25px;
    left: 0;
    font-size: 1.2rem;
}

/* Footer */
footer {
    padding: 60px 0;
    text-align: center;
    color: var(--secondary-text);
    border-top: 1px solid var(--border-color);
}

/* Download Dropdown */
.download-wrapper {
    position: relative;
    display: inline-block;
}

.qr-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    background: rgba(30, 41, 59, 0.95);
    backdrop-filter: blur(15px);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    padding: 20px;
    margin-top: 15px;
    width: 340px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
    
    /* Animation Initial State */
    opacity: 0;
    transform: translateY(-20px);
    visibility: hidden;
    transition: all 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.download-wrapper.active .qr-dropdown {
    opacity: 1;
    transform: translateY(0);
    visibility: visible;
}

/* Arrow indicator */
.qr-dropdown::before {
    content: '';
    position: absolute;
    top: -8px;
    right: 40px;
    width: 16px;
    height: 16px;
    background: rgba(30, 41, 59, 0.95);
    transform: rotate(45deg);
    border-top: 1px solid var(--border-color);
    border-left: 1px solid var(--border-color);
}

.qr-codes {
    display: flex;
    justify-content: space-between;
    gap: 20px;
}

.qr-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.qr-box {
    width: 120px;
    height: 120px;
    background: white;
    padding: 8px;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.qr-box img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.qr-item span {
    color: var(--secondary-text);
    font-size: 0.9rem;
    font-weight: 500;
}

/* Hero Button specific adjustment */
.hero .qr-dropdown {
    right: 50%;
    transform: translateX(50%) translateY(-20px);
    top: 110%;
}

.hero .download-wrapper.active .qr-dropdown {
    transform: translateX(50%) translateY(0);
}

.hero .qr-dropdown::before {
    right: 50%;
    transform: translateX(50%) rotate(45deg);
}

/* Responsive */
@media (max-width: 768px) {
    .qr-codes {
        gap: 20px;
    }
    
    .qr-box {
        width: 120px;
        height: 120px;
    }

    .hero h1 {
        font-size: 2.8rem;
    }
    
    .nav-links {
        display: none; /* Simple hiding for mobile for now */
    }

    .scenario-item {
        flex-direction: column;
        text-align: center;
        gap: 30px;
    }

    .scenario-item:nth-child(even) {
        flex-direction: column;
    }

    .chat-message {
        text-align: left;
    }
}