:root {
    /* Safe color defaults - can be refined if UI assets are inspected more closely */
    --primary-color: #5E5CE6;
    /* iOS Indigo-like */
    --primary-hover: #4744D4;
    --bg-color: #F2F2F7;
    /* iOS System Gray 6 (Light) */
    --card-bg: rgba(255, 255, 255, 0.8);
    --text-color: #1C1C1E;
    --text-secondary: #8E8E93;
    --border-color: rgba(60, 60, 67, 0.1);
    --nav-bg: rgba(255, 255, 255, 0.85);

    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.08);

    --transition-speed: 0.3s;
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

[data-theme="dark"] {
    --bg-color: #000000;
    --card-bg: rgba(28, 28, 30, 0.8);
    --text-color: #FFFFFF;
    --text-secondary: #98989D;
    --border-color: rgba(84, 84, 88, 0.4);
    --nav-bg: rgba(28, 28, 30, 0.85);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color var(--transition-speed), color var(--transition-speed);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

/* Header */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 64px;
    background: var(--nav-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: background-color var(--transition-speed), border-color var(--transition-speed);
}

.header-content {
    max-width: 1000px;
    margin: 0 auto;
    height: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 24px;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-color);
}

.logo-container img {
    height: 32px;
    width: 32px;
    border-radius: 8px;
}

.logo-text {
    font-weight: 700;
    font-size: 20px;
    letter-spacing: -0.5px;
}

.controls {
    display: flex;
    gap: 16px;
    align-items: center;
}

.btn-icon {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-color);
    font-size: 16px;
    padding: 8px;
    border-radius: 8px;
    transition: background-color 0.2s;
    font-weight: 500;
}

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

/* Main Content */
main {
    padding-top: 80px;
    /* Header height + spacing */
    max-width: 1000px;
    margin: 0 auto;
    padding-left: 24px;
    padding-right: 24px;
    padding-bottom: 60px;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 80px 0;
    animation: fadeIn 0.8s ease-out;
}

.hero h1 {
    font-size: 48px;
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -1px;
    background: linear-gradient(135deg, var(--text-color) 0%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 20px;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 40px;
}

.download-btn {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    padding: 14px 32px;
    border-radius: 99px;
    font-weight: 600;
    text-decoration: none;
    transition: transform 0.2s, background-color 0.2s, box-shadow 0.2s;
    box-shadow: var(--shadow-md);
}

.download-btn:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 12px 30px rgba(94, 92, 230, 0.4);
}

/* Features Grid */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    margin-top: 60px;
}

.feature-card {
    background: var(--card-bg);
    padding: 32px;
    border-radius: 20px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: transform 0.3s, box-shadow 0.3s;
    backdrop-filter: blur(10px);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    font-size: 32px;
    margin-bottom: 16px;
    color: var(--primary-color);
}

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

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

/* Footer */
footer {
    text-align: center;
    padding: 40px 0;
    color: var(--text-secondary);
    font-size: 14px;
    border-top: 1px solid var(--border-color);
    margin-top: 80px;
}

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

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

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 36px;
    }

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

    header {
        padding: 0 16px;
    }

    main {
        padding-left: 16px;
        padding-right: 16px;
    }
}