/* Hao 2.0 — a quiet, paper-like interface.
 *
 * Design notes:
 *   - one warm neutral background, white surfaces, hairline borders;
 *   - depth comes from a very soft shadow, never from heavy borders;
 *   - a single ink-blue accent, used sparingly (primary action, links, focus);
 *   - everything tokenised so a future theme only has to touch :root.
 */

:root {
  --bg: #f4f3f0;
  --surface: #ffffff;
  --surface-alt: #fbfaf7;
  --surface-sunk: #f6f5f1;
  --border: #e6e4dd;
  --border-strong: #d5d2c8;
  --text: #1c1c1a;
  --text-soft: #3d3c37;
  --muted: #6f6c64;
  --accent: #1b5a99;
  --accent-hover: #164a7e;
  --accent-soft: #e8f0f9;
  --accent-ink: #ffffff;
  --danger: #a32d2d;
  --danger-hover: #8c2626;
  --danger-soft: #fdf1f1;
  --danger-border: #f1d3d3;

  --radius: 16px;
  --radius-sm: 10px;
  --shadow-card: 0 1px 2px rgba(28, 28, 26, 0.04), 0 18px 36px -24px rgba(28, 28, 26, 0.35);
  --shadow-btn: 0 1px 2px rgba(28, 28, 26, 0.08);
  --ring: 0 0 0 3px var(--accent-soft);

  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, "Helvetica Neue", Arial,
    "PingFang SC", "Microsoft YaHei", sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

::selection {
  background: var(--accent-soft);
}

h1 {
  margin: 0 0 10px;
  font-size: 22px;
  font-weight: 500;
  letter-spacing: -0.015em;
}

h2 {
  margin: 0 0 6px;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: -0.005em;
}

p {
  margin: 0 0 12px;
}

/* ---------- Shell ---------- */

.shell {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100%;
  max-width: 780px;
  margin: 0 auto;
  padding: 28px 16px;
}

.panel {
  display: flex;
  flex-direction: column;
  width: 100%;
  max-width: 520px;
  padding: 34px 34px 30px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
}

.panel[hidden],
.chat[hidden] {
  display: none;
}

.eyebrow {
  margin-bottom: 10px;
  color: var(--muted);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.lede {
  margin-bottom: 24px;
  max-width: 46ch;
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.7;
}

/* ---------- Form controls ---------- */

.field {
  display: block;
  margin-bottom: 16px;
}

.field > span {
  display: block;
  margin-bottom: 7px;
  color: var(--text-soft);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.01em;
}

.field input[type="password"],
.field input[type="text"] {
  max-width: 420px;
}

input[type="password"],
input[type="text"],
textarea {
  width: 100%;
  padding: 11px 13px;
  color: var(--text);
  font-family: inherit;
  font-size: 14px;
  line-height: 1.5;
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}

input::placeholder,
textarea::placeholder {
  color: #a5a29a;
}

input[type="password"]:focus,
input[type="text"]:focus,
textarea:focus {
  background: var(--surface);
  border-color: var(--accent);
  box-shadow: var(--ring);
}

/* ---------- Buttons ---------- */

button {
  font-family: inherit;
  font-size: 14px;
  font-weight: 500;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease,
    transform 0.08s ease, box-shadow 0.15s ease;
}

button.primary {
  padding: 10px 20px;
  color: var(--accent-ink);
  background: var(--accent);
  border: 1px solid var(--accent);
  box-shadow: var(--shadow-btn);
}

button.primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}

button.primary:active {
  transform: translateY(1px);
  box-shadow: none;
}

button.primary:disabled {
  opacity: 0.55;
  cursor: default;
  transform: none;
}

button.ghost {
  padding: 7px 13px;
  color: var(--muted);
  background: transparent;
  border: 1px solid var(--border);
}

button.ghost:hover {
  color: var(--text);
  background: var(--surface-alt);
  border-color: var(--border-strong);
}

a,
button,
input,
textarea,
.file-btn {
  outline: none;
}

a:focus-visible,
button:focus-visible,
.file-btn:focus-within {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.panel .primary {
  align-self: flex-start;
  margin-top: 8px;
}

.warn,
.error {
  margin: 18px 0 0;
  font-size: 12.5px;
  line-height: 1.6;
}

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

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

.link {
  color: var(--accent);
  text-underline-offset: 2px;
}

/* ---------- Chat ---------- */

.chat {
  display: flex;
  flex-direction: column;
  align-self: stretch;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
}

.chat-head {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
}

.brand-dot {
  width: 7px;
  height: 7px;
  background: var(--accent);
  border-radius: 50%;
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.brand {
  font-size: 13.5px;
  font-weight: 500;
  letter-spacing: 0.01em;
}

.spacer {
  flex: 1;
}

.messages {
  flex: 1;
  padding: 20px 20px 8px;
  overflow-y: auto;
  scroll-behavior: smooth;
  scrollbar-width: thin;
  scrollbar-color: var(--border-strong) transparent;
}

.messages::-webkit-scrollbar {
  width: 10px;
}

.messages::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  background-clip: content-box;
  border: 3px solid transparent;
  border-radius: 999px;
}

.messages::-webkit-scrollbar-thumb:hover {
  background: var(--muted);
  background-clip: content-box;
}

/* Empty state: #messages is genuinely empty until the first message lands. */
#messages:empty::before {
  display: block;
  padding: 40px 24px;
  color: #a5a29a;
  font-size: 13px;
  line-height: 1.7;
  text-align: center;
  content: "No messages yet. Anything you send is encrypted in this browser before it leaves.";
}

.msg {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  margin-bottom: 16px;
  animation: msg-in 0.18s ease-out;
}

@keyframes msg-in {
  from {
    opacity: 0;
    transform: translateY(4px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.msg .meta {
  margin-bottom: 4px;
  color: var(--muted);
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.01em;
}

.msg .bubble {
  max-width: 82%;
  padding: 10px 14px;
  overflow-wrap: anywhere;
  white-space: pre-wrap;
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: 14px 14px 14px 5px;
}

.msg .bubble.broken {
  color: var(--muted);
  font-style: italic;
}

.file-link {
  padding: 0;
  color: var(--accent);
  font-size: 14px;
  font-weight: 500;
  text-align: left;
  text-decoration: underline;
  text-underline-offset: 2px;
  background: none;
  border: none;
  word-break: break-all;
}

.file-link:hover {
  color: var(--accent-hover);
}

.file-link:disabled {
  color: var(--muted);
  cursor: default;
  text-decoration: none;
}

.file-size {
  margin-left: 8px;
  color: var(--muted);
  font-size: 12px;
  font-variant-numeric: tabular-nums;
}

.status {
  min-height: 22px;
  margin: 0;
  padding: 0 20px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.8;
}

.status[data-tone="error"] {
  color: var(--danger);
}

.composer {
  padding: 12px 20px 18px;
  border-top: 1px solid var(--border);
}

.composer textarea {
  resize: none;
  min-height: 62px;
  padding: 12px 14px;
  border-radius: 12px;
}

.composer-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 10px;
}

.file-btn {
  display: inline-flex;
  align-items: center;
  padding: 8px 14px;
  color: var(--muted);
  font-size: 13px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}

.file-btn:hover {
  color: var(--text);
  background: var(--surface-alt);
  border-color: var(--border-strong);
}

.composer-actions .primary {
  margin-left: auto;
}

/* ---------- Admin page ---------- */

.shell.admin {
  display: block;
  height: auto;
  min-height: 100%;
  max-width: 600px;
  padding: 40px 20px 64px;
  overflow-y: auto;
}

.shell.admin > h1 {
  margin-bottom: 8px;
}

.shell.admin > .lede {
  max-width: 66ch;
  margin-bottom: 26px;
}

.card {
  padding: 24px;
  margin-bottom: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: 0 1px 2px rgba(28, 28, 26, 0.03);
}

.card.danger {
  background: var(--danger-soft);
  border-color: var(--danger-border);
}

.card.danger .primary {
  background: var(--danger);
  border-color: var(--danger);
}

.card.danger .primary:hover {
  background: var(--danger-hover);
  border-color: var(--danger-hover);
}

.card .primary {
  margin-top: 8px;
}

.hint {
  max-width: 68ch;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.7;
}

code {
  padding: 1px 6px;
  font-family: var(--mono);
  font-size: 12px;
  background: var(--surface-sunk);
  border: 1px solid var(--border);
  border-radius: 5px;
}

.log {
  margin: 0;
  padding: 14px 16px;
  min-height: 96px;
  max-height: 240px;
  overflow: auto;
  color: var(--text-soft);
  font-family: var(--mono);
  font-size: 12px;
  line-height: 1.75;
  white-space: pre-wrap;
  background: var(--surface-sunk);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
}

/* ---------- Small screens ---------- */

@media (max-width: 620px) {
  .shell {
    padding: 0;
  }

  .shell.admin {
    padding: 24px 14px 48px;
  }

  .panel {
    max-width: none;
    margin: 16px;
    padding: 26px 22px;
  }

  .chat {
    border: none;
    border-radius: 0;
    box-shadow: none;
  }

  .chat-head,
  .composer {
    padding-left: 14px;
    padding-right: 14px;
  }

  .messages {
    padding: 16px 14px 6px;
  }

  .status {
    padding: 0 14px;
  }

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

@media (prefers-reduced-motion: reduce) {
  .messages {
    scroll-behavior: auto;
  }

  .msg {
    animation: none;
  }

  button,
  input,
  textarea,
  .file-btn {
    transition: none;
  }
}