:root {
    --bg-color: #f0f9ff;
    /* Sky 50 - Very pale blue */
    --text-primary: #1e293b;
    /* Slate 800 - Dark text */
    --text-secondary: #64748b;
    /* Slate 500 - Muted text */
    --accent-primary: #0284c7;
    /* Sky 600 - Darker accent for contrast */
    --accent-secondary: #0ea5e9;
    /* Sky 500 */
    --card-bg: rgba(255, 255, 255, 0.7);
    /* Whitish glass */
    --card-border: rgba(255, 255, 255, 0.8);
    --font-main: 'Inter', 'Noto Sans JP', sans-serif;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-main);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 24px;
    -webkit-font-smoothing: antialiased;
}

/* Background Effects - Subtle modern mesh */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background:
        radial-gradient(circle at 0% 0%, rgba(14, 165, 233, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 100% 100%, rgba(56, 189, 248, 0.15) 0%, transparent 50%);
    z-index: -1;
    pointer-events: none;
}

.container {
    width: 100%;
    max-width: 500px;
    display: flex;
    flex-direction: column;
    gap: 40px;
}

/* Header */
header {
    text-align: center;
    padding: 24px 0 10px;
    animation: fadeInDown 0.8s ease-out;
}

h1 {
    font-size: 2.2rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    /* Gradient text but darker for light mode */
    background: linear-gradient(135deg, #0ea5e9 0%, #2563eb 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.25rem;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin-bottom: 24px;
}

.intro-text {
    text-align: left;
    background: rgba(255, 255, 255, 0.6);
    padding: 20px;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.8);
    color: var(--text-primary);
    font-size: 0.9rem;
    line-height: 1.7;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.intro-text p+p {
    margin-top: 12px;
}

/* Tweet Section */
.tweet-container {
    width: 100%;
    display: flex;
    justify-content: center;
    min-height: 200px;
    animation: fadeIn 1s ease-out 0.2s backwards;
}

/* Twitter widget overrides likely needed? 
   Actually Twitter widget handles light mode by default unless data-theme="dark" is forced.
   We need to change data-theme in HTML.
*/

/* Download Cards */
.download-section {
    display: flex;
    flex-direction: column;
    gap: 16px;
    width: 100%;
    animation: fadeInUp 0.8s ease-out 0.4s backwards;
}

.dl-card {
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 16px;
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    color: var(--text-primary);
    text-decoration: none;
    padding: 20px;
    border-radius: 16px;
    backdrop-filter: blur(12px);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.dl-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
    transform: translateX(-100%);
    transition: transform 0.6s;
}

.dl-card:hover::before {
    transform: translateX(100%);
}

.dl-card:hover,
.dl-card:active {
    transform: translateY(-2px);
    background: rgba(255, 255, 255, 0.9);
    border-color: rgba(14, 165, 233, 0.4);
    box-shadow: 0 10px 15px -3px rgba(14, 165, 233, 0.15);
}

.card-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, rgba(224, 242, 254, 1), rgba(240, 249, 255, 1));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--accent-primary);
    border: 1px solid rgba(14, 165, 233, 0.2);
}

.card-content {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.card-label {
    font-size: 0.7rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.card-title {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
}

.card-desc {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.arrow-icon {
    width: 20px;
    height: 20px;
    color: var(--text-secondary);
    transition: transform 0.3s ease;
}

.dl-card:hover .arrow-icon {
    transform: translateX(4px);
    color: var(--accent-primary);
}

/* Footer */
footer {
    text-align: center;
    color: var(--text-secondary);
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
    /* Softer border for light mode */
    width: 100%;
}

.small-text {
    font-size: 0.75rem;
    opacity: 0.8;
    margin-top: 4px;
}

/* Animations */
.announcement-title {
    display: block;
    width: 100%;
    text-align: center;
    margin-left: auto;
    margin-right: auto;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--accent-primary);
    margin-bottom: 1rem;
    /* More space */
    animation: fadeInDown 0.8s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }

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

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

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