/* ==========================
   Reset
========================== */

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

html,
body {
    width: 100%;
    height: 100%;
    font-family: Inter, system-ui, sans-serif;
    background: #111827;
    color: #f3f4f6;
}

body {
    overflow: hidden;
}

/* ==========================
   Layout
========================== */

.app {
    display: flex;
    width: 100vw;
    height: 100vh;
}

/* ==========================
   Sidebar
========================== */

.sidebar {
    width: 260px;
    background: #0b1220;
    border-right: 1px solid #1f2937;

    display: flex;
    flex-direction: column;
}

.sidebar-header {
    padding: 16px;
}

.new-chat-btn {
    width: 100%;
    border: none;
    border-radius: 10px;
    background: #1f2937;
    color: white;
    padding: 12px;
    cursor: pointer;
    transition: 0.2s;
}

.new-chat-btn:hover {
    background: #374151;
}

.chat-list {
    flex: 1;
    overflow-y: auto;
    padding: 12px;
}

.sidebar-footer {
    padding: 16px;
    border-top: 1px solid #1f2937;
}

/* ==========================
   Main Area
========================== */

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: #111827;
}

/* ==========================
   Top Bar
========================== */

.topbar {
    height: 64px;
    border-bottom: 1px solid #1f2937;

    display: flex;
    align-items: center;
    justify-content: space-between;

    padding: 0 24px;
}

.model-selector {
    background: #1f2937;
    padding: 10px 14px;
    border-radius: 8px;
    font-size: 14px;
}

.topbar-actions {
    display: flex;
    gap: 12px;
}

/* ==========================
   Chat Area
========================== */

.chat-container {
    flex: 1;
    overflow-y: auto;

    display: flex;
    justify-content: center;
    align-items: center;

    padding: 40px;
}

.welcome-screen {
    text-align: center;
    opacity: 0.75;
}

.welcome-screen h1 {
    font-size: 2rem;
    margin-bottom: 12px;
}

.welcome-screen p {
    color: #9ca3af;
}

/* ==========================
   Input Area
========================== */

.input-area {
    padding: 20px;
    display: flex;
    justify-content: center;

    border-top: 1px solid #1f2937;
}

.input-wrapper {
    width: 100%;
    max-width: 900px;

    display: flex;
    align-items: flex-end;
    gap: 12px;

    background: #1f2937;
    border: 1px solid #374151;
    border-radius: 18px;

    padding: 12px;
}

.input-wrapper textarea {
    flex: 1;

    background: transparent;
    border: none;
    outline: none;

    resize: none;

    color: white;
    font-size: 15px;
    line-height: 1.5;
}

.input-wrapper textarea::placeholder {
    color: #9ca3af;
}

.send-btn {
    width: 40px;
    height: 40px;

    border: none;
    border-radius: 10px;

    background: #3b82f6;
    color: white;

    cursor: pointer;
    font-size: 16px;

    transition: 0.2s;
}

.send-btn:hover {
    background: #2563eb;
}

/* ==========================
   Responsive
========================== */

@media (max-width: 768px) {
    .sidebar {
        width: 72px;
    }

    .topbar {
        padding: 0 16px;
    }

    .input-wrapper {
        max-width: 100%;
    }
}