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

:root {
    /* Light theme (default) */
    --bg-color: #f5f5f5;
    --container-bg: #ffffff;
    --text-color: #1a1a1a;
    --text-secondary: #666666;
    --button-bg: #ffffff;
    --button-border: #e0e0e0;
    --button-hover: #f8f8f8;
    --shadow: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #ffffff;
    --text-secondary: #b0b0b0;
    --button-bg: #3a3a3a;
    --button-border: #4a4a4a;
    --button-hover: #454545;
    --shadow: rgba(0, 0, 0, 0.3);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 60px 30px 20px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 680px;
    width: 100%;
    position: relative;
}

.profile {
    text-align: center;
    margin-bottom: 40px;
    padding: 32px;
    background: var(--container-bg);
    border-radius: 24px;
    box-shadow: 0 4px 16px var(--shadow);
    transition: all 0.3s ease;
}

.qr-code {
    width: 180px;
    height: 180px;
    margin: 0 auto 24px;
    display: block;
    border-radius: 16px;
    box-shadow: 0 4px 12px var(--shadow);
    transition: all 0.3s ease;
}

.qr-code:hover {
    transform: scale(1.05);
    box-shadow: 0 6px 20px var(--shadow);
}

.profile h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 12px;
    letter-spacing: -0.5px;
}

.bio {
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.5;
    max-width: 400px;
    margin: 0 auto;
}

.links {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.link-button {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 20px 24px;
    background: var(--button-bg);
    border: 2px solid var(--button-border);
    border-radius: 12px;
    text-decoration: none;
    color: var(--text-color);
    font-size: 16px;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 2px 8px var(--shadow);
}

.link-button:hover {
    background: var(--button-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow);
}

.link-button:active {
    transform: translateY(0);
}

.link-button .icon {
    font-size: 24px;
}

.theme-toggle {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: var(--button-bg);
    border: 2px solid var(--button-border);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px var(--shadow);
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 16px var(--shadow);
}

.theme-toggle:active {
    transform: scale(0.95);
}

.price-tag {
    display: block;
    font-size: 0.75rem;
    opacity: 0.7;
    margin-top: 2px;
    font-weight: 400;
}

@media (max-width: 768px) {
    .profile h1 {
        font-size: 20px;
    }
    
    .link-button {
        padding: 16px 20px;
        font-size: 15px;
    }
    
    .theme-toggle {
        width: 48px;
        height: 48px;
        bottom: 10px;
        right: 20px;
    }
}