:root {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --border-color: #334155;
    --input-bg: #334155;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    margin: 0;
    padding: 0;
    min-height: 100vh;
    display: flex;
    justify-content: center;
}

.app-container {
    width: 100%;
    max-width: 1200px;
    padding: 20px;
    display: flex;
    flex-direction: column;
    height: 100vh;
    box-sizing: border-box;
}

.main-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    margin-bottom: 40px;
    border-bottom: 1px solid var(--border-color);
}

.logo {
    font-size: 1.5rem;
    font-weight: 600;
    background: linear-gradient(to right, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    margin-left: 20px;
    transition: color 0.2s;
}

.nav-link:hover {
    color: var(--text-primary);
}

/* Forms & Cards */
.card {
    background-color: var(--card-bg);
    border-radius: 16px;
    padding: 40px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-secondary);
}

input[type="text"],
input[type="password"] {
    width: 100%;
    padding: 12px;
    background-color: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 1rem;
    box-sizing: border-box;
}

input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

.btn {
    background-color: var(--accent-color);
    color: white;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.2s;
    width: 100%;
}

.btn:hover {
    background-color: var(--accent-hover);
}

/* Persona Selection */
.persona-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.persona-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 30px;
    cursor: pointer;
    transition: transform 0.2s, border-color 0.2s;
    text-align: center;
}

.persona-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent-color);
}

.persona-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.persona-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 10px;
}

.persona-desc {
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Chat Interface */
.chat-container {
    display: flex;
    flex-direction: column;
    height: calc(100vh - 180px);
    /* Adjust based on header */
    background-color: var(--card-bg);
    border-radius: 16px;
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.chat-messages {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.message {
    max-width: 80%;
    padding: 15px;
    border-radius: 12px;
    line-height: 1.5;
}

.message.user {
    align-self: flex-end;
    background-color: var(--accent-color);
    color: white;
    border-bottom-right-radius: 4px;
}

.message.assistant {
    align-self: flex-start;
    background-color: var(--input-bg);
    color: var(--text-primary);
    border-bottom-left-radius: 4px;
}

.chat-input-area {
    padding: 20px;
    background-color: rgba(30, 41, 59, 0.5);
    border-top: 1px solid var(--border-color);
    display: flex;
    gap: 10px;
}

.chat-input-area input {
    flex: 1;
}

.chat-input-area button {
    width: auto;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-color);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}