.site-header {
    background: rgba(30, 58, 95, 0.7);
    backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 2rem;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    gap: 1rem;
}

.logo-link {
    display: flex;
    align-items: center;
    gap: 1rem;
    text-decoration: none;
    transition: transform 0.3s ease;
}

.logo-link:hover {
    transform: translateY(-2px);
}

.logo-link svg {
    flex-shrink: 0;
    filter: drop-shadow(0 4px 12px rgba(37, 99, 235, 0.4));
}

.logo-text {
    display: flex;
    flex-direction: column;
}

.logo-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #ffffff;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

.logo-subtitle {
    font-size: 0.875rem;
    font-weight: 500;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.2;
}

.auth-container {
    display: flex;
    align-items: center;
    margin-left: auto;
}

.login-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 1.25rem 2.5rem;
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 18px;
    font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', system-ui, sans-serif;
    font-size: 1.0625rem;
    font-weight: 600;
    color: #ffffff;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
    height: 40px;
    min-width: 180px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.login-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(255, 255, 255, 0.15);
}

.login-btn:active {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(0);
}

.login-btn:focus-visible {
    outline: 2px solid rgba(255, 255, 255, 0.5);
    outline-offset: 2px;
}

.google-icon {
    flex-shrink: 0;
    width: 18px;
    height: 18px;
}

.login-text {
    font-weight: 600;
    letter-spacing: 0.25px;
    white-space: nowrap;
}

.login-btn.loading {
    pointer-events: none;
    opacity: 0.6;
}

.login-btn.loading .google-icon {
    animation: spin 0.7s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.user-profile-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 4px 12px 4px 4px;
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 20px;
    color: #ffffff;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    height: 40px;
}

.user-profile-btn:hover {
    transform: translateY(-2px);
    background: rgba(255, 255, 255, 0.3);
    box-shadow: 0 8px 24px rgba(255, 255, 255, 0.15);
}

.user-profile-btn:active {
    transform: translateY(0);
}

.user-profile-btn:focus-visible {
    outline: 2px solid rgba(255, 255, 255, 0.5);
    outline-offset: 2px;
}

.user-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    border: 2px solid rgba(255, 255, 255, 0.9);
    object-fit: cover;
    flex-shrink: 0;
}

.user-name {
    font-size: 14px;
    max-width: 120px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

@media (max-width: 768px) {
    .header-inner {
        height: 56px;
    }
    
    .logo-link svg {
        width: 28px;
        height: 28px;
    }
    
    .logo-title {
        font-size: 1.25rem;
    }
    
    .logo-subtitle {
        font-size: 0.75rem;
    }
    
    .login-btn {
        min-width: 160px;
        padding: 1rem 1.5rem;
    }
    
    .user-name {
        max-width: 100px;
    }
}

@media (max-width: 640px) {
    .header-inner {
        height: 52px;
    }
    
    .logo-link {
        gap: 8px;
    }
    
    .logo-link svg {
        width: 24px;
        height: 24px;
    }
    
    .logo-title {
        font-size: 1.125rem;
    }
    
    .logo-subtitle {
        display: none;
    }
    
    .login-btn {
        min-width: auto;
        padding: 1rem 1.25rem;
        gap: 8px;
    }
    
    .login-text {
        display: none;
    }
    
    .google-icon {
        width: 20px;
        height: 20px;
    }
    
    .user-profile-btn {
        padding: 4px 8px 4px 4px;
    }
    
    .user-avatar {
        width: 28px;
        height: 28px;
    }
    
    .user-name {
        display: none;
    }
}

@media (max-width: 480px) {
    .header-container {
        padding: 0 0.75rem;
    }
    
    .header-inner {
        height: 48px;
    }
    
    .login-btn,
    .user-profile-btn {
        height: 36px;
    }
}

@media (prefers-reduced-motion: reduce) {
    .login-btn,
    .user-profile-btn,
    .logo-link {
        transition: none;
    }
    
    .login-btn.loading .google-icon {
        animation: none;
    }
    
    .user-profile-btn:hover {
        transform: none;
    }
}

@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    .google-icon,
    .user-avatar {
        image-rendering: -webkit-optimize-contrast;
        image-rendering: crisp-edges;
    }
}

@media print {
    .site-header {
        position: static;
        box-shadow: none;
        border-bottom: 1px solid rgba(255, 255, 255, 0.5);
    }
    
    .auth-container {
        display: none;
    }
}