/* ========== 主区域 ========== */
.main-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 100vh;
    min-width: 0;
    background: var(--color-bg);
    position: relative;
}

.chat-header {
    padding: 16px 24px;
    background: var(--color-white);
    border-bottom: 2px solid var(--color-border);
    display: flex;
    align-items: center;
    gap: 12px;
    box-shadow: var(--shadow-sm);
    flex-shrink: 0;
    min-height: 60px;
    flex-wrap: wrap;
}
.chat-header-label {
    font-weight: 700;
    font-size: var(--font-size-lg);
    color: var(--color-text);
    white-space: nowrap;
}
.chat-header-model {
    font-size: var(--font-size-md);
    color: var(--color-primary);
    background: var(--color-primary-light);
    padding: 6px 14px;
    border-radius: 20px;
    font-weight: 600;
    white-space: nowrap;
}

/* 空状态 */
.empty-state {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 16px;
    padding: 40px 24px;
    text-align: center;
    color: var(--color-text-light);
    min-height: 300px;
}
.empty-state-icon {
    font-size: 80px;
    margin-bottom: 8px;
    animation: float 3s ease-in-out infinite;
}
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}
.empty-state-text {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text);
}
.empty-state-sub {
    font-size: var(--font-size-md);
    color: var(--color-text-light);
    line-height: 1.8;
}