.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 50;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    height: 70px;
    width: 100%;
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 0 var(--spacing-md);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    text-decoration: none;
    color: inherit;
    transition: transform var(--transition-fast);
}

.logo-icon {
    position: relative;
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.25rem;
    overflow: hidden;
    transition: all var(--transition-base);
}

.logo-icon::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, transparent 30%, rgba(255, 255, 255, 0.1) 50%, transparent 70%);
    transform: translateX(-100%);
    transition: transform 0.6s;
}

.logo:hover .logo-icon::before {
    transform: translateX(100%);
}

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

.logo-title {
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    background: var(--gradient-logo);
    background-size: 300% 100%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    animation: gradientFlow 8s ease infinite;
    transition: all var(--transition-base);
}

.logo-subtitle {
    font-size: 0.75rem;
    color: var(--color-text-tertiary);
    font-weight: 500;
    transition: all var(--transition-base);
}

.theme-switch {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.theme-switch:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--color-border-hover);
    box-shadow: 0 0 15px rgba(255, 255, 255, 0.1);
}

.theme-switch i {
    font-size: 1.25rem;
    transition: transform var(--transition-base);
    z-index: 1;
}

.theme-dark .theme-switch i {
    color: #cbe4f5;
}

.theme-light .theme-switch i {
    color: #f59e0b;
}