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

body {
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
    color: #ffffff;
    background-color: #121212;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header */
.site-header {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    padding: 20px 40px;
    z-index: 10;
    display: flex;
    align-items: center;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: 15px;
}

.logo {
    height: 50px;
    width: auto;
}

.app-name {
    font-size: 1.5rem;
    font-weight: bold;
    color: #fff;
    text-shadow: 0 2px 4px rgba(0,0,0,0.5);
}

/* Main / Hero Section */
.hero-section {
    flex: 1;
    background-image: url('assets/header_haruna_dark.png');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    display: flex;
    align-items: center; /* 垂直居中 */
    position: relative;
}

/* Overlay for better text readability if needed */
.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(to right, rgba(0,0,0,0.8) 0%, rgba(0,0,0,0.3) 50%, rgba(0,0,0,0) 100%);
    z-index: 1;
}

.content-container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px;
    position: relative;
    z-index: 2;
}

.intro-text {
    max-width: 500px;
}

.intro-text h1 {
    font-size: 4rem;
    margin-bottom: 20px;
    text-shadow: 0 4px 6px rgba(0,0,0,0.5);
}

.intro-text p {
    font-size: 1.5rem;
    margin-bottom: 15px;
    line-height: 1.6;
    text-shadow: 0 2px 4px rgba(0,0,0,0.5);
}

.download-buttons {
    margin-top: 40px;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    background-color: #007AFF;
    color: white;
    text-decoration: none;
    border-radius: 25px;
    font-weight: bold;
    transition: background-color 0.3s;
}

.btn:hover {
    background-color: #0056b3;
}

/* Footer */
.site-footer {
    background-color: #000;
    padding: 20px;
    text-align: center;
    font-size: 0.9rem;
    color: #888;
}

.site-footer a {
    color: #888;
    text-decoration: none;
}

.site-footer a:hover {
    text-decoration: underline;
}