/* ========================================
   CHAT PAGE STYLES
======================================== */

/* Layout */
.chat-page {
    display: flex;
    height: 100vh;
    overflow: hidden;
    background: var(--bg-primary);
}

/* Sidebar */
.chat-sidebar {
    width: 17.5rem;
    background: var(--bg-secondary);
    border-right: 0.0625rem solid var(--border-color);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    transition: transform var(--transition-base), width var(--transition-base);
}

.chat-sidebar.collapsed {
    width: 0;
    transform: translateX(-100%);
}

.sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.25rem;
    border-bottom: 0.0625rem solid var(--border-color);
}

.sidebar-logo {
    display: flex;
    align-items: center;
    gap: 0.625rem;
    text-decoration: none;
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.sidebar-logo-icon {
    width: 2.25rem;
    height: 2.25rem;
    background: var(--gradient-primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
}

.sidebar-toggle {
    width: 2.25rem;
    height: 2.25rem;
    background: var(--bg-tertiary);
    border: 0.0625rem solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.sidebar-toggle:hover {
    color: var(--text-primary);
    border-color: var(--accent-primary);
}

.new-chat-btn {
    margin: 1rem;
    padding: 0.875rem 1.25rem;
    background: var(--gradient-primary);
    border: none;
    border-radius: var(--radius-lg);
    color: white;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.625rem;
    transition: all var(--transition-base);
}

.new-chat-btn:hover {
    transform: translateY(-0.125rem);
    box-shadow: var(--shadow-glow);
}

.sidebar-section {
    padding: 1rem;
    flex: 1;
    overflow-y: auto;
}

.sidebar-section-title {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

/* Subject Selector */
.subject-selector {
    display: flex;
    flex-direction: column;
    gap: 0.375rem;
}

.subject-btn {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 0.875rem;
    background: transparent;
    border: 0.0625rem solid transparent;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-align: left;
}

.subject-btn:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.subject-btn.active {
    background: rgba(245, 158, 11, 0.1);
    border-color: rgba(245, 158, 11, 0.3);
    color: var(--accent-primary);
}

.subject-btn span {
    font-size: 1.2rem;
}

/* Session List */
.session-list {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.session-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.session-item:hover {
    background: var(--bg-tertiary);
}

.session-item.active {
    background: var(--bg-tertiary);
    border: 0.0625rem solid var(--border-color);
}

.session-icon {
    font-size: 1.25rem;
}

.session-info {
    flex: 1;
    min-width: 0;
}

.session-title {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.session-time {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Sidebar Footer */
.sidebar-footer {
    padding: 1rem;
    border-top: 0.0625rem solid var(--border-color);
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-lg);
}

.user-avatar {
    width: 2.5rem;
    height: 2.5rem;
    background: var(--gradient-secondary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    color: white;
    flex-shrink: 0;
}

.user-info {
    flex: 1;
    min-width: 0;
}

.user-name {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
}

.user-grade {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.user-menu-btn {
    width: 2rem;
    height: 2rem;
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
}

.user-menu-btn:hover {
    background: var(--bg-primary);
    color: var(--text-primary);
}

/* Main Chat Area */
.chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

/* Chat Header */
.chat-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.5rem;
    background: var(--bg-secondary);
    border-bottom: 0.0625rem solid var(--border-color);
}

.mobile-menu-btn {
    display: none;
    width: 2.5rem;
    height: 2.5rem;
    background: var(--bg-tertiary);
    border: 0.0625rem solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    cursor: pointer;
    align-items: center;
    justify-content: center;
}

.chat-header-info {
    flex: 1;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.chat-subject-badge {
    display: flex;
    align-items: center;
    gap: 0.625rem;
    padding: 0.5rem 1rem;
    background: var(--bg-tertiary);
    border: 0.0625rem solid var(--border-color);
    border-radius: var(--radius-full);
}

.chat-subject-icon {
    font-size: 1.2rem;
}

.chat-subject-name {
    font-weight: 600;
    color: var(--text-primary);
}

.chat-status {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--accent-success);
}

.status-dot {
    width: 0.5rem;
    height: 0.5rem;
    background: var(--accent-success);
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
}

.chat-header-actions {
    display: flex;
    gap: 0.5rem;
}

.header-action-btn {
    width: 2.5rem;
    height: 2.5rem;
    background: var(--bg-tertiary);
    border: 0.0625rem solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.header-action-btn:hover {
    color: var(--text-primary);
    border-color: var(--accent-primary);
}

/* Chat Messages */
.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* Welcome Message */
.message-welcome {
    text-align: center;
    padding: 3rem 1.5rem;
    max-width: 37.5rem;
    margin: auto;
}

.welcome-icon {
    font-size: 4rem;
    margin-bottom: 1.5rem;
}

.message-welcome h2 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.message-welcome p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 2rem;
}

.suggested-questions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    justify-content: center;
}

.suggested-btn {
    padding: 0.75rem 1.25rem;
    background: var(--bg-card);
    border: 0.0625rem solid var(--border-color);
    border-radius: var(--radius-full);
    color: var(--text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.suggested-btn:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    background: rgba(245, 158, 11, 0.1);
}

/* Messages */
.message {
    display: flex;
    gap: 1rem;
    max-width: 56.25rem;
    animation: messageSlide 0.3s ease;
}

@keyframes messageSlide {
    from { opacity: 0; transform: translateY(0.625rem); }
    to { opacity: 1; transform: translateY(0); }
}

.message.user {
    flex-direction: row-reverse;
    margin-left: auto;
}

.message-avatar {
    width: 2.5rem;
    height: 2.5rem;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.ai-avatar {
    background: var(--gradient-primary);
    color: white;
}

.user-avatar-small {
    background: var(--gradient-secondary);
    color: white;
    font-weight: 600;
    font-size: 0.85rem;
}

.message-content {
    flex: 1;
    min-width: 0;
}

.message-text {
    padding: 1rem 1.25rem;
    border-radius: var(--radius-xl);
    line-height: 1.7;
}

.message.user .message-text {
    background: var(--gradient-primary);
    color: white;
    border-bottom-right-radius: 0.375rem;
}

.message.assistant .message-text {
    background: var(--bg-card);
    border: 0.0625rem solid var(--border-color);
    color: var(--text-primary);
    border-bottom-left-radius: 0.375rem;
}

.message-text p {
    margin-bottom: 0.75rem;
}

.message-text p:last-child {
    margin-bottom: 0;
}

.message-text code {
    font-family: var(--font-mono);
    background: var(--bg-tertiary);
    padding: 0.125rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.9em;
}

.message-text ol, .message-text ul {
    margin: 0.75rem 0;
    padding-left: 1.5rem;
}

.message-text li {
    margin-bottom: 0.5rem;
}

.math-block {
    background: var(--bg-tertiary);
    border: 0.0625rem solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem 1.25rem;
    margin: 1rem 0;
    font-family: var(--font-mono);
    font-size: 1.1rem;
    text-align: center;
    color: var(--accent-primary);
}

.message-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.75rem;
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.message:hover .message-actions {
    opacity: 1;
}

.message-action {
    width: 2rem;
    height: 2rem;
    background: var(--bg-tertiary);
    border: 0.0625rem solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-muted);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.message-action:hover {
    color: var(--accent-primary);
    border-color: var(--accent-primary);
}

.message-time {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
}

.message.user .message-time {
    text-align: right;
}

/* Chat Input */
.chat-input-container {
    padding: 1rem 1.5rem 1.5rem;
    background: var(--bg-secondary);
    border-top: 0.0625rem solid var(--border-color);
}

.chat-input-wrapper {
    display: flex;
    align-items: flex-end;
    gap: 0.75rem;
    background: var(--bg-card);
    border: 0.0625rem solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: 0.75rem 1rem;
    transition: border-color var(--transition-fast);
}

.chat-input-wrapper:focus-within {
    border-color: var(--accent-primary);
}

.input-action-btn {
    width: 2.5rem;
    height: 2.5rem;
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all var(--transition-fast);
}

.input-action-btn:hover {
    color: var(--text-primary);
    background: var(--bg-tertiary);
}

.chat-input {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 1rem;
    line-height: 1.5;
    resize: none;
    max-height: 9.375rem;
    padding: 0.5rem 0;
}

.chat-input:focus {
    outline: none;
}

.chat-input::placeholder {
    color: var(--text-muted);
}

.send-btn {
    width: 2.75rem;
    height: 2.75rem;
    background: var(--gradient-primary);
    border: none;
    border-radius: var(--radius-lg);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all var(--transition-base);
}

.send-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.send-btn:not(:disabled):hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-glow);
}

.chat-input-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0.25rem 0;
}

.input-hint, .char-count {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Typing Indicator */
.typing-indicator {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 0;
}

.typing-dots {
    display: flex;
    gap: 0.25rem;
}

.typing-dots span {
    width: 0.5rem;
    height: 0.5rem;
    background: var(--accent-primary);
    border-radius: 50%;
    animation: typingBounce 1.4s ease-in-out infinite;
}

.typing-dots span:nth-child(2) { animation-delay: 0.2s; }
.typing-dots span:nth-child(3) { animation-delay: 0.4s; }

@keyframes typingBounce {
    0%, 80%, 100% { transform: translateY(0); opacity: 0.4; }
    40% { transform: translateY(-0.5rem); opacity: 1; }
}

/* Responsive */
@media (max-width: 48em) {
    .chat-sidebar {
        position: fixed;
        left: 0;
        top: 0;
        bottom: 0;
        z-index: 100;
        transform: translateX(-100%);
    }

    .chat-sidebar.open {
        transform: translateX(0);
    }

    .mobile-menu-btn {
        display: flex;
    }

    .chat-messages {
        padding: 1rem;
    }

    .chat-input-container {
        padding: 0.75rem 1rem 1rem;
    }

    .message-welcome {
        padding: 2rem 1rem;
    }

    .suggested-questions {
        flex-direction: column;
    }

    .suggested-btn {
        width: 100%;
    }
}