:root {
    /* Dark Mode (Default) */
    --bg-color: #0f0f0f;
    --text-color: #ffffff;
    --accent-color: #ffffff;
    --accent-text: #000000;
    --box-bg: #1a1a1a;
    --box-border: #333333;
    --box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
    --secondary-text: #888888;
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;
}

body.light-mode {
    /* Light Mode */
    --bg-color: #ffffff;
    --text-color: #1a1a1a;
    --accent-color: #000000;
    --accent-text: #ffffff;
    --box-bg: #ffffff;
    --box-border: #e5e5e5;
    --box-shadow: 0 4px 20px rgba(0, 0, 0, 0.03);
    --secondary-text: #666666;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-main);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
    box-sizing: border-box;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    text-align: center;
    width: 100%;
    max-width: 500px;
}

/* Top Navigation */
.top-nav {
    position: fixed;
    top: 20px;
    right: 20px;
    display: flex;
    align-items: center;
    gap: 15px;
    z-index: 100;
}

.github-link {
    color: var(--secondary-text);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    transition: color 0.2s ease;
    opacity: 0.8;
}

.github-link:hover {
    color: var(--text-color);
    opacity: 1;
}

/* Toggle Button */
.theme-toggle {
    background: transparent;
    border: 1px solid var(--box-border);
    color: var(--text-color);
    padding: 8px 16px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.theme-toggle:hover {
    background: var(--box-bg);
}

header h1 {
    font-weight: 600;
    font-size: 2rem;
    letter-spacing: -0.03em;
    margin-bottom: 0.5rem;
}

header p {
    color: var(--secondary-text);
    margin-bottom: 2.5rem;
    font-weight: 300;
}

.result-box {
    background: var(--box-bg);
    border: 1px solid var(--box-border);
    border-radius: 16px;
    padding: 3rem 2rem;
    box-shadow: var(--box-shadow);
    margin-bottom: 2rem;
    font-size: 1.25rem;
    line-height: 1.5;
    font-weight: 400;
    min-height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s ease, background 0.3s ease, border-color 0.3s ease;
}

.result-box:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.1);
}

.refresh-btn {
    background-color: var(--accent-color);
    color: var(--accent-text);
    border: none;
    padding: 0.8rem 2rem;
    border-radius: 50px;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: var(--font-main);
}

.refresh-btn:hover {
    transform: scale(1.02);
    opacity: 0.9;
}

.refresh-btn:active {
    transform: scale(0.98);
}

.loader {
    color: var(--secondary-text);
    font-size: 1rem;
    font-style: italic;
}

/* Mobile adjustments */
@media (max-width: 480px) {
    header h1 {
        font-size: 1.75rem;
    }

    .result-box {
        padding: 2rem 1.5rem;
    }

    .top-nav {
        top: 15px;
        right: 15px;
        gap: 10px;
    }

    .github-link span {
        display: none;
    }
}