:root {
    --primary: #5b4bdb;
    --secondary: #7c3aed;
    --bg: #f5f6fa;
    --card: #ffffff;
    --text: #1f2937;
}

* { 
    box-sizing: border-box; 
    font-family: 'Inter', system-ui, sans-serif; 
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    height: 100vh;
    overflow: hidden;
}

.app {
    display: grid;
    grid-template-columns: 260px 1fr 1fr;
    height: 100vh;
}

/* SIDEBAR */
.sidebar {
    background: linear-gradient(180deg, var(--primary), var(--secondary));
    color: #fff;
    padding: 16px;
    display: flex;
    flex-direction: column;
}

.logo {
    font-weight: bold;
    font-size: 18px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.menu {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.menu button {
    width: 100%;
    padding: 12px;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    background: rgba(255,255,255,0.15);
    color: #fff;
    font-size: 14px;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 8px;
}

.menu button:hover {
    background: rgba(255,255,255,0.25);
    transform: translateY(-2px);
}

/* CHAT */
.chat {
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.chat-box {
    flex: 1;
    background: var(--card);
    border-radius: 10px;
    padding: 16px;
    overflow-y: auto;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.msg {
    margin-bottom: 12px;
    padding: 12px;
    border-radius: 8px;
    line-height: 1.5;
}

.msg.ai {
    background: #eef2ff;
    border-left: 4px solid var(--primary);
}

.msg.user {
    background: #e5e7eb;
    border-right: 4px solid #6b7280;
    text-align: right;
}

.input-area {
    display: flex;
    gap: 8px;
}

input {
    flex: 1;
    padding: 12px;
    border-radius: 8px;
    border: 1px solid #ddd;
    font-size: 14px;
    transition: all 0.2s ease;
}

input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(91, 75, 219, 0.2);
}

button.send {
    padding: 12px 16px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s ease;
}

button.send:hover {
    background: var(--secondary);
    transform: translateY(-1px);
}

/* PREVIEW */
.preview {
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.preview-header button {
    padding: 6px 12px;
    background: var(--card);
    border: 1px solid #ddd;
    border-radius: 6px;
    cursor: pointer;
    font-size: 12px;
    transition: all 0.2s ease;
}

.preview-header button:hover {
    background: #f3f4f6;
}

.preview iframe {
    width: 100%;
    height: calc(100% - 40px);
    border-radius: 10px;
    border: 1px solid #ddd;
    background: white;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

/* Responsive */
@media (max-width: 1024px) {
    .app {
        grid-template-columns: 200px 1fr;
    }
    .preview {
        display: none;
    }
}

@media (max-width: 768px) {
    .app {
        grid-template-columns: 1fr;
        grid-template-rows: auto 1fr;
    }
    .sidebar {
        grid-row: 1;
        grid-column: 1;
        flex-direction: row;
        align-items: center;
        padding: 12px;
    }
    .logo {
        margin-bottom: 0;
        margin-right: 16px;
    }
    .menu {
        flex-direction: row;
        overflow-x: auto;
        padding-bottom: 8px;
    }
    .menu button {
        white-space: nowrap;
    }
    .chat {
        grid-row: 2;
        grid-column: 1;
    }
}