:root {
    --bg-main: #FAF9F6;
    --bg-sidebar: #F0EDE8;
    --text-primary: #1A1A1A;
    --text-secondary: #6B6B6B;
    --accent: #D97757;
    --accent-hover: #C06648;
    --user-bubble-bg: #EBE8E3;
    --input-bg: #FFFFFF;
    --input-border: #E8E5E0;
    --shadow-soft: 0 2px 8px rgba(0, 0, 0, 0.06);
    --shadow-medium: 0 4px 16px rgba(0, 0, 0, 0.08);
    --border-radius: 14px;
    --border-radius-lg: 16px;
    --font-serif: 'Source Serif 4', Georgia, serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --sidebar-width: 260px;
    --chat-max-width: 720px;
    --transition: all 0.2s ease;
}

[data-theme="dark"] {
    --bg-main: #1A1918;
    --bg-sidebar: #242220;
    --text-primary: #F5F5F4;
    --text-secondary: #A8A8A7;
    --accent: #D97757;
    --accent-hover: #E88564;
    --user-bubble-bg: #2C2B29;
    --input-bg: #242220;
    --input-border: #3A3835;
    --shadow-soft: 0 2px 8px rgba(0, 0, 0, 0.2);
    --shadow-medium: 0 4px 16px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-main);
    color: var(--text-primary);
    line-height: 1.6;
    height: 100vh;
    overflow: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.app-container {
    display: flex;
    height: 100%;
    width: 100%;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background-color: var(--bg-sidebar);
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--input-border);
    flex-shrink: 0;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.sidebar-header {
    padding: 1.25rem;
}

.new-chat-btn {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem 1rem;
    background-color: var(--bg-main);
    border: 1px solid var(--input-border);
    border-radius: var(--border-radius);
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.new-chat-btn:hover {
    background-color: var(--user-bubble-bg);
    border-color: var(--text-secondary);
}

.new-chat-btn svg {
    width: 18px;
    height: 18px;
    flex-shrink: 0;
}

.conversation-history {
    flex: 1;
    overflow-y: auto;
    padding: 0 1.25rem;
}

.history-section {
    margin-bottom: 1.5rem;
}

.history-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}

.history-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.625rem 0.75rem;
    border-radius: 8px;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-primary);
    font-size: 0.9rem;
}

.history-item:hover {
    background-color: var(--user-bubble-bg);
}

.history-item svg {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
    color: var(--text-secondary);
}

.history-item span {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.sidebar-footer {
    padding: 1rem 1.25rem;
    border-top: 1px solid var(--input-border);
}

.model-selector {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
    background-color: var(--bg-main);
    border-radius: var(--border-radius);
    margin-bottom: 0.75rem;
    cursor: pointer;
    transition: var(--transition);
}

.model-selector:hover {
    background-color: var(--user-bubble-bg);
}

.model-label {
    font-size: 0.9rem;
    font-weight: 500;
}

.chevron-down {
    width: 16px;
    height: 16px;
    color: var(--text-secondary);
}

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

.sidebar-icon-btn {
    background: transparent;
    border: none;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 0.625rem;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

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

.sidebar-icon-btn svg {
    width: 20px;
    height: 20px;
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    background-color: var(--bg-main);
    position: relative;
}

#chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 2rem 1rem;
    display: flex;
    justify-content: center;
}

#messages {
    width: 100%;
    max-width: var(--chat-max-width);
    display: flex;
    flex-direction: column;
    gap: 2rem;
    padding-bottom: 2rem;
}

.message {
    display: flex;
    flex-direction: column;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.ai-message {
    align-self: flex-start;
    max-width: 100%;
}

.ai-label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.375rem;
    font-family: var(--font-sans);
}

.user-message {
    align-self: flex-end;
    max-width: 80%;
}

.user-message .message-content {
    background-color: var(--user-bubble-bg);
    padding: 0.875rem 1.25rem;
    border-radius: var(--border-radius-lg);
    color: var(--text-primary);
    font-size: 0.95rem;
}

.message-content {
    white-space: pre-wrap;
    word-break: break-word;
    font-family: var(--font-serif);
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-primary);
}

.user-message .message-content {
    font-family: var(--font-sans);
    line-height: 1.5;
}

.typing {
    display: flex;
    gap: 6px;
    padding: 0.5rem 0;
}

.dot {
    width: 7px;
    height: 7px;
    background: var(--text-secondary);
    border-radius: 50%;
    animation: bounce 1.4s infinite ease-in-out both;
}

.dot:nth-child(1) {
    animation-delay: -0.32s;
}

.dot:nth-child(2) {
    animation-delay: -0.16s;
}

@keyframes bounce {
    0%, 80%, 100% {
        transform: scale(0);
    }
    40% {
        transform: scale(1);
    }
}

/* Input Area */
.input-area {
    padding: 1rem 1rem 1.5rem;
    display: flex;
    justify-content: center;
    background-color: var(--bg-main);
}

.input-wrapper {
    width: 100%;
    max-width: var(--chat-max-width);
    background-color: var(--input-bg);
    border-radius: var(--border-radius-lg);
    padding: 0.75rem 1rem;
    display: flex;
    align-items: flex-end;
    gap: 0.75rem;
    box-shadow: var(--shadow-soft);
    border: 1px solid var(--input-border);
    transition: var(--transition);
}

.input-wrapper:focus-within {
    box-shadow: var(--shadow-medium);
    border-color: var(--accent);
}

#user-input {
    flex: 1;
    border: none;
    background: transparent;
    resize: none;
    outline: none;
    font-size: 0.95rem;
    font-family: var(--font-serif);
    color: var(--text-primary);
    padding: 0.5rem 0;
    max-height: 200px;
    line-height: 1.6;
}

#user-input::placeholder {
    color: var(--text-secondary);
    font-family: var(--font-sans);
}

#send-btn {
    background: var(--accent);
    border: none;
    cursor: pointer;
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
    border-radius: 10px;
    transition: var(--transition);
    margin-bottom: 0.125rem;
}

#send-btn:hover:not(:disabled) {
    background: var(--accent-hover);
    transform: scale(1.05);
}

#send-btn:disabled {
    background: var(--text-secondary);
    opacity: 0.4;
    cursor: default;
    transform: none;
}

#send-btn svg {
    width: 18px;
    height: 18px;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 100;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
}

.modal-content {
    background-color: var(--bg-main);
    padding: 2rem;
    border-radius: var(--border-radius-lg);
    width: 90%;
    max-width: 480px;
    box-shadow: var(--shadow-medium);
    color: var(--text-primary);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.modal-header h2 {
    font-weight: 600;
    font-size: 1.25rem;
    font-family: var(--font-sans);
}

.close-btn {
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    line-height: 1;
    transition: var(--transition);
}

.close-btn:hover {
    color: var(--text-primary);
}

.settings-group {
    margin-bottom: 1.5rem;
}

.settings-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    font-size: 0.9rem;
    font-family: var(--font-sans);
}

.settings-group input[type="password"] {
    width: 100%;
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--input-border);
    background-color: var(--input-bg);
    color: var(--text-primary);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    outline: none;
    transition: var(--transition);
}

.settings-group input[type="password"]:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(217, 119, 87, 0.1);
}

.custom-dropdown {
    position: relative;
    width: 100%;
    user-select: none;
}

.dropdown-selected {
    padding: 0.75rem 1rem;
    background-color: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: var(--border-radius);
    color: var(--text-primary);
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    transition: var(--transition);
    font-family: var(--font-sans);
    font-size: 0.95rem;
}

.dropdown-selected:hover {
    border-color: var(--accent);
}

.dropdown-arrow {
    width: 18px;
    height: 18px;
    stroke: var(--text-secondary);
    transition: transform 0.2s ease;
}

.custom-dropdown.active .dropdown-arrow {
    transform: rotate(180deg);
}

.dropdown-options {
    position: absolute;
    top: calc(100% + 0.5rem);
    left: 0;
    width: 100%;
    background-color: var(--bg-main);
    border: 1px solid var(--input-border);
    border-radius: var(--border-radius);
    overflow: hidden;
    display: none;
    z-index: 10;
    box-shadow: var(--shadow-medium);
}

.custom-dropdown.active .dropdown-options {
    display: block;
}

.dropdown-options .option {
    padding: 0.75rem 1rem;
    cursor: pointer;
    color: var(--text-primary);
    transition: var(--transition);
    font-family: var(--font-sans);
    font-size: 0.95rem;
}

.dropdown-options .option:hover {
    background-color: var(--user-bubble-bg);
}

.dropdown-options .option.selected {
    background-color: rgba(217, 119, 87, 0.15);
    color: var(--accent);
    font-weight: 500;
}

.save-btn {
    width: 100%;
    padding: 0.875rem;
    border-radius: var(--border-radius);
    border: none;
    background: var(--accent);
    color: white;
    font-weight: 600;
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    transition: var(--transition);
}

.save-btn:hover {
    background: var(--accent-hover);
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--text-secondary);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-primary);
}