:root {
    --bg: #f4f8ff;
    --surface: #ffffff;
    --ink: #14213d;
    --muted: #5d6b8a;
    --brand: #0f766e;
    --brand-2: #155e75;
    --danger: #b42318;
    --line: #d8e1f0;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    color: var(--ink);
    background: radial-gradient(circle at top right, #ddf5f3, var(--bg) 40%);
}

.container {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 1rem;
}

.card {
    width: min(100%, 460px);
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 18px;
    padding: 1.25rem;
    box-shadow: 0 20px 40px rgba(20, 33, 61, 0.08);
}

h1 {
    margin: 0 0 .45rem 0;
    font-size: 1.4rem;
}

.muted {
    color: var(--muted);
}

.small {
    font-size: .86rem;
}

.stack {
    display: grid;
    gap: .8rem;
}

input,
textarea,
button {
    width: 100%;
    border: 1px solid var(--line);
    border-radius: 10px;
    font-size: 1rem;
    padding: .7rem .8rem;
}

button {
    border: none;
    background: linear-gradient(120deg, var(--brand), var(--brand-2));
    color: #fff;
    font-weight: 600;
    cursor: pointer;
}

.secondary {
    background: #e7edf8;
    color: var(--ink);
}

.danger {
    width: auto;
    padding: .6rem .8rem;
    background: var(--danger);
}

.hidden {
    display: none;
}

.error {
    color: var(--danger);
    margin: 0;
}

.loader {
    width: 40px;
    height: 40px;
    border-radius: 999px;
    border: 3px solid #c8d2e4;
    border-top-color: var(--brand);
    animation: spin 1s linear infinite;
    margin-inline: auto;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.chat-shell {
    width: min(920px, 100%);
    margin: 1rem auto;
    padding: 1rem;
    display: grid;
    gap: .8rem;
}

.chat-header {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 14px;
    padding: .8rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: .8rem;
}

.chat-log {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 14px;
    min-height: 52vh;
    max-height: 62vh;
    overflow-y: auto;
    padding: .8rem;
    display: grid;
    gap: .6rem;
}

.msg {
    max-width: 76%;
    padding: .6rem .75rem;
    border-radius: 12px;
    word-break: break-word;
}

.incoming {
    background: #e6f0ff;
    justify-self: start;
}

.outgoing {
    background: #cdeeea;
    justify-self: end;
}

.msg img {
    max-width: 100%;
    border-radius: 10px;
    display: block;
}

.chat-form {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 14px;
    padding: .8rem;
    display: grid;
    gap: .65rem;
}

.chat-actions {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: .6rem;
    align-items: center;
}

.chat-actions button {
    width: auto;
    min-width: 100px;
}

@media (max-width: 720px) {
    .chat-shell {
        margin: 0;
        padding: .55rem;
    }

    .chat-log {
        min-height: 58vh;
    }

    .chat-actions {
        grid-template-columns: 1fr;
    }

    .chat-actions button {
        width: 100%;
    }

    .msg {
        max-width: 90%;
    }
}