:root {
    /* Light Theme (Default) */
    --bg-color: #ffffff;
    --bg-gradient: radial-gradient(circle at center 10%, #f0f4ff 0%, #ffffff 60%);
    --text-primary: #1f1f1f;
    --text-secondary: #5e5e5e;
    --input-bg: #f3f4f6;
    --input-border: #e5e7eb;
    --user-msg-bg: #f3f4f6;
    --ai-msg-bg: transparent;
    --code-bg: #f6f8fa;
    --code-header: #e1e4e8;
    --title-gradient: linear-gradient(90deg, #4285f4, #9b72cb);
    --transition: 0.3s ease;
}

body.dark-mode {
    /* Dark Theme */
    --bg-color: #0f1115;
    --bg-gradient: radial-gradient(circle at center 10%, #171d2b 0%, #0f1115 60%);
    --text-primary: #e3e3e3;
    --text-secondary: #a0a0a0;
    --input-bg: #1e1f25;
    --input-border: #33343c;
    --user-msg-bg: #2d2d30;
    --ai-msg-bg: transparent;
    --code-bg: #1e1e1e;
    --code-header: #2d2d2d;
    --title-gradient: linear-gradient(90deg, #d3c4ff, #9fb4ff);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    height: 100vh;
    display: flex;
    overflow: hidden;
    transition: background-color var(--transition), color var(--transition);
}

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

/* Top Controls */
.top-controls {
    position: absolute;
    top: 20px;
    width: 100%;
    display: flex;
    justify-content: space-between;
    padding: 0 20px;
    z-index: 100;
}

.icon-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s, color 0.2s;
}

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

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 100%;
    position: relative;
    background: var(--bg-gradient);
    transition: all 0.5s ease, background var(--transition);
}

.main-content.welcome-mode {
    justify-content: center;
}

.chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 60px 20px 20px 20px; 
    display: flex;
    flex-direction: column;
    align-items: center;
    scroll-behavior: smooth;
    width: 100%;
}

.main-content.welcome-mode .chat-container {
    flex: none;
    overflow-y: visible;
    padding-top: 20px;
}

.welcome-screen {
    text-align: center;
    padding: 20px;
    width: 100%;
    max-width: 800px;
}

.welcome-title {
    font-size: 36px;
    font-weight: 400;
    margin-bottom: 20px;
    background: var(--title-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.messages-list {
    width: 100%;
    max-width: 800px;
    display: flex;
    flex-direction: column;
    gap: 30px;
    padding-bottom: 40px;
}

.message {
    display: flex;
    animation: fadeIn 0.3s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.message.user {
    background-color: var(--user-msg-bg);
    align-self: flex-end;
    max-width: 85%;
    border-radius: 20px;
    padding: 12px 20px;
}

.message.ai {
    background-color: var(--ai-msg-bg);
    align-self: flex-start;
    width: 100%;
    padding: 12px 0;
    flex-direction: column;
}

.message-content {
    width: 100%;
    overflow-x: auto;
    font-size: 16px;
}

.message-content p {
    margin-bottom: 15px;
}

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

/* Action Icons */
.message-actions {
    display: flex;
    gap: 8px;
    margin-top: 10px;
    opacity: 1;
}

.icon-action-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 6px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s, color 0.2s;
}

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

/* Markdown Styles & Code Blocks */
.code-block-wrapper {
    background-color: var(--code-bg);
    border-radius: 8px;
    margin: 15px 0;
    overflow: hidden;
    border: 1px solid var(--input-border);
}

.code-block-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 15px;
    background-color: var(--code-header);
    font-size: 12px;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--input-border);
}

.code-lang {
    text-transform: uppercase;
    font-weight: 600;
    letter-spacing: 0.5px;
}

.code-copy-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 12px;
    transition: color 0.2s;
}

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

.message-content pre {
    padding: 15px;
    overflow-x: auto;
    margin: 0;
}

.message-content code {
    font-family: 'Courier New', Courier, monospace;
    font-size: 14px;
}

.message-content :not(pre) > code {
    background-color: var(--code-bg);
    padding: 2px 6px;
    border-radius: 4px;
}

/* Input Area */
.input-container {
    padding: 0 20px 20px 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
}

.chat-form {
    width: 100%;
    max-width: 800px;
}

.input-wrapper {
    display: flex;
    align-items: center;
    background-color: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 30px;
    padding: 10px 20px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    transition: box-shadow var(--transition), border-color var(--transition), background-color var(--transition);
}

textarea {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-family: inherit;
    font-size: 16px;
    resize: none;
    max-height: 200px;
    padding: 8px 0;
    outline: none;
}

textarea::placeholder {
    color: var(--text-secondary);
}

.send-btn {
    background: transparent;
    color: var(--text-secondary);
    border: none;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: color 0.2s;
    margin-left: 10px;
    flex-shrink: 0;
    padding: 5px;
}

.send-btn:hover:not(:disabled) {
    color: var(--text-primary);
}

.send-btn:disabled {
    cursor: not-allowed;
    opacity: 0.3;
}

.disclaimer {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 15px;
    text-align: center;
    max-width: 800px;
}

.cursor-blink {
    display: inline-block;
    width: 8px;
    height: 16px;
    background-color: var(--text-primary);
    animation: blink 1s step-end infinite;
    vertical-align: text-bottom;
    margin-left: 4px;
}

@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0; }
}

@media (max-width: 768px) {
    .message.user {
        max-width: 95%;
    }
    
    .welcome-title {
        font-size: 28px;
    }
}