:root {
    --brand-accent: #1E88E5;
    --brand-accent-hover: #1976D2;
    --brand-dark: #1a1a2e;
    --brand-darker: #16162a;
    --brand-surface: #222244;
    --brand-surface-light: #2a2a4e;
    --brand-text: #e8e8f0;
    --brand-text-muted: #9999bb;
    --brand-border: #333366;
    --brand-success: #4caf50;
    --brand-error: #ef5350;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--brand-dark);
    color: var(--brand-text);
    height: 100vh;
    overflow: hidden;
}

.login-container {
    display: flex; align-items: center; justify-content: center; height: 100vh;
    background: linear-gradient(135deg, var(--brand-dark), var(--brand-darker));
}

.login-card {
    background: var(--brand-surface); border-radius: 16px; padding: 48px;
    width: 400px; max-width: 90vw; box-shadow: 0 20px 60px rgba(0,0,0,0.4); text-align: center;
}

.login-card h1 { font-size: 24px; margin-bottom: 8px; color: var(--brand-accent); }
.login-card p { color: var(--brand-text-muted); margin-bottom: 32px; }

.form-group { margin-bottom: 20px; text-align: left; }
.form-group label { display: block; margin-bottom: 6px; font-size: 14px; color: var(--brand-text-muted); }
.form-group input {
    width: 100%; padding: 12px 16px; border: 1px solid var(--brand-border); border-radius: 8px;
    background: var(--brand-darker); color: var(--brand-text); font-size: 16px; outline: none; transition: border-color 0.2s;
}
.form-group input:focus { border-color: var(--brand-accent); }

.btn { display: inline-block; padding: 12px 24px; border: none; border-radius: 8px; font-size: 16px; font-weight: 600; cursor: pointer; transition: all 0.2s; width: 100%; }
.btn-primary { background: var(--brand-accent); color: #fff; }
.btn-primary:hover { background: var(--brand-accent-hover); transform: translateY(-1px); }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }

.error-msg { color: var(--brand-error); font-size: 14px; margin-top: 12px; display: none; }
.success-msg { color: var(--brand-success); font-size: 14px; margin-top: 12px; display: none; }

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

.sidebar {
    width: 280px; background: var(--brand-darker); border-right: 1px solid var(--brand-border);
    display: flex; flex-direction: column; flex-shrink: 0;
}

.sidebar-header { padding: 20px; border-bottom: 1px solid var(--brand-border); display: flex; align-items: center; gap: 12px; }
.sidebar-header h2 { font-size: 16px; color: var(--brand-accent); }
.sidebar-user { padding: 16px 20px; border-bottom: 1px solid var(--brand-border); font-size: 13px; color: var(--brand-text-muted); }
.sidebar-user .name { color: var(--brand-text); font-weight: 600; }
.sidebar-actions { padding: 12px; }

.btn-new-chat {
    width: 100%; padding: 10px; background: var(--brand-accent); color: #fff;
    border: none; border-radius: 8px; font-weight: 600; cursor: pointer; font-size: 14px;
}
.btn-new-chat:hover { opacity: 0.9; }

.conversation-list { flex: 1; overflow-y: auto; padding: 8px 12px; }
.conversation-item { padding: 10px 12px; border-radius: 8px; cursor: pointer; font-size: 13px; color: var(--brand-text-muted); margin-bottom: 4px; transition: background 0.15s; }
.conversation-item:hover { background: var(--brand-surface); }
.conversation-item.active { background: var(--brand-surface); color: var(--brand-text); }

.sidebar-footer { padding: 12px 20px; border-top: 1px solid var(--brand-border); font-size: 12px; color: var(--brand-text-muted); }

.chat-main { flex: 1; display: flex; flex-direction: column; }
.chat-header { padding: 16px 24px; border-bottom: 1px solid var(--brand-border); display: flex; justify-content: space-between; align-items: center; }
.chat-header h3 { font-size: 16px; color: var(--brand-text); }
.chat-messages { flex: 1; overflow-y: auto; padding: 24px; display: flex; flex-direction: column; gap: 16px; }

.message { max-width: 80%; padding: 14px 18px; border-radius: 12px; font-size: 15px; line-height: 1.6; white-space: pre-wrap; word-wrap: break-word; }
.message.user { align-self: flex-end; background: var(--brand-accent); color: #fff; border-bottom-right-radius: 4px; }
.message.assistant { align-self: flex-start; background: var(--brand-surface); border-bottom-left-radius: 4px; }
.message.system { align-self: center; background: transparent; color: var(--brand-text-muted); font-size: 13px; font-style: italic; }

.tool-indicator { display: inline-flex; align-items: center; gap: 6px; padding: 6px 12px; background: var(--brand-surface-light); border-radius: 6px; font-size: 12px; color: var(--brand-text-muted); margin: 4px 0; }
.tool-indicator.success { border-left: 3px solid var(--brand-success); }
.tool-indicator.pending { border-left: 3px solid var(--brand-accent); }

.quick-actions { display: flex; gap: 8px; padding: 12px 24px; flex-wrap: wrap; }
.quick-action { padding: 8px 16px; background: var(--brand-surface); border: 1px solid var(--brand-border); border-radius: 20px; color: var(--brand-text-muted); font-size: 13px; cursor: pointer; transition: all 0.15s; }
.quick-action:hover { border-color: var(--brand-accent); color: var(--brand-accent); }

.chat-input-area { padding: 16px 24px; border-top: 1px solid var(--brand-border); display: flex; gap: 12px; }
.chat-input-area textarea { flex: 1; padding: 12px 16px; border: 1px solid var(--brand-border); border-radius: 12px; background: var(--brand-surface); color: var(--brand-text); font-size: 15px; font-family: inherit; resize: none; outline: none; min-height: 48px; max-height: 150px; }
.chat-input-area textarea:focus { border-color: var(--brand-accent); }

.btn-send { padding: 12px 20px; background: var(--brand-accent); color: #fff; border: none; border-radius: 12px; font-weight: 600; cursor: pointer; align-self: flex-end; }
.btn-send:hover { opacity: 0.9; }
.btn-send:disabled { opacity: 0.4; cursor: not-allowed; }

.cost-badge { font-size: 11px; color: var(--brand-text-muted); padding: 2px 8px; background: var(--brand-surface); border-radius: 4px; }

@media (max-width: 768px) { .sidebar { display: none; } .message { max-width: 95%; } }