/* Zeta Chat - Minimal Style */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg: #ffffff;
    --bg-secondary: #f7f7f8;
    --bg-sidebar: #171717;
    --text: #0d0d0d;
    --text-secondary: #6b6b6b;
    --text-light: #ececec;
    --border: #e5e5e5;
    --accent: #10a37f;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    height: 100vh;
}

.chat-app {
    display: flex;
    height: 100vh;
}

/* SIDEBAR */
.sidebar {
    width: 260px;
    background: var(--bg-sidebar);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
}

.sidebar-header {
    padding: 12px;
}

.new-chat-btn {
    width: 100%;
    padding: 12px 16px;
    background: transparent;
    border: 1px solid rgba(255,255,255,0.2);
    border-radius: 8px;
    color: var(--text-light);
    font-size: 14px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: background 0.2s;
}

.new-chat-btn:hover {
    background: rgba(255,255,255,0.1);
}

.sidebar-content {
    flex: 1;
    overflow-y: auto;
    padding: 8px 12px;
}

.sidebar-footer {
    padding: 12px;
    border-top: 1px solid rgba(255,255,255,0.1);
}

.sidebar-footer select {
    width: 100%;
    padding: 8px 12px;
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 6px;
    color: var(--text-light);
    font-size: 13px;
    cursor: pointer;
}

/* MAIN */
.main {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--bg);
}

.chat-container {
    flex: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

/* WELCOME */
.welcome {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px;
    text-align: center;
}

.welcome-logo {
    width: 72px;
    height: 72px;
    border-radius: 50%;
    background: var(--bg-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    color: var(--text-secondary);
}

.welcome h1 {
    font-size: 28px;
    font-weight: 500;
    color: var(--text);
}

/* MESSAGES */
.messages {
    max-width: 768px;
    margin: 0 auto;
    padding: 24px;
    width: 100%;
}

.message {
    display: flex;
    gap: 16px;
    padding: 24px 0;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

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

.avatar {
    width: 32px;
    height: 32px;
    border-radius: 4px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 600;
}

.avatar.user {
    background: var(--accent);
    color: white;
}

.avatar.assistant {
    background: var(--bg-sidebar);
    color: white;
}

.message-content {
    flex: 1;
    line-height: 1.6;
    font-size: 15px;
    max-width: 85%;
}

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

.message-content p { margin-bottom: 12px; }
.message-content p:last-child { margin-bottom: 0; }

.message-content strong { font-weight: 600; }
.message-content code {
    background: var(--bg-secondary);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 13px;
}

/* Streaming cursor */
.cursor {
    display: inline-block;
    width: 8px;
    height: 18px;
    background: var(--accent);
    margin-left: 2px;
    animation: blink 0.8s infinite;
    vertical-align: text-bottom;
}

@keyframes blink {
    0%, 50% { opacity: 1; }
    51%, 100% { opacity: 0; }
}

/* INPUT */
.input-area {
    padding: 16px 24px 24px;
    background: var(--bg);
}

.input-wrapper {
    max-width: 768px;
    margin: 0 auto;
    display: flex;
    align-items: flex-end;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 12px 16px;
    gap: 12px;
}

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

#message-input {
    flex: 1;
    border: none;
    background: transparent;
    font-size: 15px;
    resize: none;
    outline: none;
    max-height: 200px;
    line-height: 1.5;
    font-family: inherit;
}

.send-btn {
    width: 32px;
    height: 32px;
    border: none;
    border-radius: 6px;
    background: var(--accent);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: opacity 0.2s;
    flex-shrink: 0;
}

.send-btn:hover { opacity: 0.9; }
.send-btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* RESPONSIVE */
@media (max-width: 768px) {
    .sidebar {
        display: none;
    }
    .messages {
        padding: 16px;
    }
    .input-area {
        padding: 12px 16px 16px;
    }
}