:root {
  --background: #f5f2ea;
  --surface: #fffdf8;
  --surface-strong: #ffffff;
  --text: #202522;
  --muted: #5f6963;
  --accent: #246b50;
  --accent-dark: #174936;
  --accent-soft: #e2efe8;
  --danger: #a02d22;
  --line: #d8ddd7;
  --shadow: 0 1rem 3rem rgba(35, 53, 44, 0.08);
  font-family: "Segoe UI", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--background);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 90% 5%, rgba(36, 107, 80, 0.14), transparent 28rem),
    var(--background);
}

[hidden] {
  display: none !important;
}

a {
  color: inherit;
}

.site-header,
main,
footer {
  width: min(1080px, calc(100% - 2.5rem));
  margin-inline: auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: 1.5rem;
}

.logo {
  display: grid;
  width: 2.8rem;
  height: 2.8rem;
  place-items: center;
  border-radius: 50%;
  background: var(--accent);
  color: white;
  font-weight: 800;
  text-decoration: none;
}

nav {
  display: flex;
  gap: clamp(1rem, 3vw, 2rem);
}

nav a {
  color: var(--muted);
  text-decoration: none;
}

nav a:hover,
nav a:focus-visible {
  color: var(--accent-dark);
}

.hero {
  min-height: 68vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  padding-block: 4rem;
}

.eyebrow,
.section-number {
  margin: 0 0 1rem;
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 800;
  letter-spacing: 0.16em;
}

h1 {
  max-width: 780px;
  margin: 0;
  font-size: clamp(2.7rem, 8vw, 6.4rem);
  line-height: 1.02;
  letter-spacing: -0.055em;
}

h2,
h3,
p {
  overflow-wrap: anywhere;
}

h2 {
  margin: 0;
  font-size: clamp(1.8rem, 4vw, 3rem);
}

h3 {
  margin: 0;
  font-size: 1.25rem;
}

.intro {
  max-width: 680px;
  margin: 2rem 0;
  color: var(--muted);
  font-size: clamp(1rem, 2vw, 1.2rem);
  line-height: 1.9;
}

button,
.file-button {
  border: 0;
  border-radius: 999px;
  padding: 0.85rem 1.3rem;
  background: var(--accent);
  color: white;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  transition: background 160ms ease, transform 160ms ease;
}

button:hover,
button:focus-visible,
.file-button:hover,
.file-button:focus-visible {
  background: var(--accent-dark);
  transform: translateY(-2px);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
  transform: none;
}

.button-secondary {
  border: 1px solid var(--line);
  background: transparent;
  color: var(--accent-dark);
}

.button-secondary:hover,
.button-secondary:focus-visible {
  background: var(--accent-soft);
}

.button-danger {
  border: 1px solid var(--danger);
  background: transparent;
  color: var(--danger);
}

.button-danger:hover,
.button-danger:focus-visible {
  background: var(--danger);
  color: white;
}

.message {
  min-height: 1.5rem;
  margin-top: 1rem;
  color: var(--accent-dark);
}

.content-section {
  display: grid;
  grid-template-columns: minmax(180px, 0.7fr) 1.3fr;
  gap: 3rem;
  padding-block: 5rem;
  border-top: 1px solid var(--line);
}

.content-section > p,
.skill-list {
  margin: 0;
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.9;
}

.skill-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  padding: 0;
  list-style: none;
}

.skill-list li {
  padding: 1.1rem;
  border: 1px solid var(--line);
  border-radius: 0.8rem;
  background: rgba(255, 253, 248, 0.7);
}

.community-section {
  padding-block: 5rem;
  border-top: 1px solid var(--line);
}

.community-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 2rem;
}

.community-intro {
  max-width: 760px;
  margin: 1.5rem 0 2.5rem auto;
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.8;
}

.connection-state {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.connection-dot {
  width: 0.7rem;
  height: 0.7rem;
  border-radius: 50%;
  background: #b65c50;
  box-shadow: 0 0 0 0.25rem rgba(182, 92, 80, 0.12);
}

.connection-dot.is-connected {
  background: #2e8b62;
  box-shadow: 0 0 0 0.25rem rgba(46, 139, 98, 0.14);
}

.auth-panel {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.25rem;
  max-width: 860px;
  margin-left: auto;
}

.auth-panel > section,
.member-panel,
.chat-shell {
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: rgba(255, 253, 248, 0.88);
  box-shadow: var(--shadow);
}

.auth-panel > section {
  padding: clamp(1.2rem, 3vw, 1.75rem);
}

.account-form {
  display: grid;
  gap: 0.7rem;
  margin-top: 1.25rem;
}

.account-form button {
  justify-self: start;
  margin-top: 0.45rem;
}

label {
  font-weight: 700;
}

input,
select,
textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 0.7rem;
  padding: 0.8rem 0.95rem;
  background: var(--surface-strong);
  color: var(--text);
  font: inherit;
}

textarea {
  resize: vertical;
}

input:focus,
select:focus,
textarea:focus {
  border-color: var(--accent);
  outline: 3px solid rgba(36, 107, 80, 0.15);
}

.field-help {
  margin: 0;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 400;
  line-height: 1.5;
}

.member-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: 860px;
  margin-left: auto;
  padding: 1rem 1.25rem;
}

.member-panel p {
  margin: 0;
}

.role-badge {
  display: inline-block;
  margin-left: 0.45rem;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-dark);
  font-size: 0.78rem;
  font-weight: 700;
}

.role-badge.is-admin {
  background: #f4dfac;
  color: #68450d;
}

.admin-panel {
  max-width: 860px;
  margin: 1.25rem 0 0 auto;
  padding: clamp(1.2rem, 3vw, 1.75rem);
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: rgba(255, 253, 248, 0.88);
  box-shadow: var(--shadow);
}

.admin-panel > header,
.admin-user-row,
.admin-user-identity,
.message-meta {
  display: flex;
  align-items: center;
}

.admin-panel > header {
  justify-content: space-between;
  gap: 1rem;
}

.admin-panel .section-number {
  margin-bottom: 0.35rem;
}

.admin-panel > .field-help {
  margin-top: 0.8rem;
}

.admin-user-list {
  display: grid;
  gap: 0.75rem;
  margin-top: 1.25rem;
}

.admin-user-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(9rem, 0.45fr) auto;
  gap: 0.75rem;
  padding: 0.85rem;
  border: 1px solid var(--line);
  border-radius: 0.8rem;
  background: var(--surface-strong);
}

.admin-user-identity {
  align-items: flex-start;
  flex-direction: column;
  gap: 0.2rem;
  min-width: 0;
}

.admin-user-identity span {
  color: var(--muted);
  font-size: 0.78rem;
}

.admin-user-row button {
  padding: 0.7rem 1rem;
}

.admin-user-actions {
  display: flex;
  gap: 0.5rem;
}

.form-status {
  display: block;
  min-height: 1.5rem;
  max-width: 860px;
  margin: 0.75rem 0 0 auto;
  color: var(--muted);
  font-size: 0.92rem;
}

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

.chat-shell {
  max-width: 860px;
  margin: 1.25rem 0 0 auto;
  overflow: hidden;
}

.message-list {
  display: flex;
  min-height: 22rem;
  max-height: 65vh;
  flex-direction: column;
  gap: 0.85rem;
  overflow-y: auto;
  padding: clamp(1rem, 3vw, 1.5rem);
  background: rgba(226, 239, 232, 0.42);
  scroll-behavior: smooth;
}

.empty-messages {
  margin: auto;
  color: var(--muted);
  text-align: center;
}

.chat-message {
  align-self: flex-start;
  width: fit-content;
  max-width: min(82%, 38rem);
  padding: 0.9rem 1rem;
  border: 1px solid var(--line);
  border-radius: 0.3rem 1rem 1rem;
  background: var(--surface-strong);
}

.chat-message.is-own-message {
  align-self: flex-end;
  border-color: rgba(36, 107, 80, 0.25);
  border-radius: 1rem 0.3rem 1rem 1rem;
  background: var(--accent-soft);
}

.chat-message header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.45rem;
}

.chat-message time {
  color: var(--muted);
  font-size: 0.75rem;
  white-space: nowrap;
}

.message-meta {
  justify-content: flex-end;
  gap: 0.55rem;
}

.message-delete-button {
  padding: 0;
  border-radius: 0;
  background: transparent;
  color: var(--danger);
  font-size: 0.75rem;
  font-weight: 700;
}

.message-delete-button:hover,
.message-delete-button:focus-visible {
  background: transparent;
  color: #721b14;
  text-decoration: underline;
  transform: none;
}

.chat-message p {
  margin: 0;
  line-height: 1.65;
  white-space: pre-wrap;
}

.message-image {
  display: block;
  width: auto;
  max-width: 100%;
  max-height: 26rem;
  margin-top: 0.7rem;
  border-radius: 0.65rem;
  object-fit: contain;
}

.typing-status {
  min-height: 1.5rem;
  margin: 0;
  padding: 0.25rem 1.5rem;
  color: var(--muted);
  font-size: 0.85rem;
}

.message-form {
  display: grid;
  gap: 0.75rem;
  padding: 1rem 1.5rem 1.5rem;
  border-top: 1px solid var(--line);
  background: var(--surface);
}

.message-actions,
.message-actions > div,
.image-preview-panel {
  display: flex;
  align-items: center;
  gap: 0.8rem;
}

.message-actions {
  justify-content: space-between;
}

.file-button {
  display: inline-block;
  padding: 0.7rem 1rem;
  font-size: 0.9rem;
}

.image-preview-panel {
  align-items: flex-start;
  padding: 0.8rem;
  border: 1px dashed var(--line);
  border-radius: 0.8rem;
}

.image-preview-panel img {
  width: 7rem;
  height: 7rem;
  border-radius: 0.6rem;
  object-fit: cover;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.visually-hidden:focus + .field-help {
  outline: 3px solid rgba(36, 107, 80, 0.15);
}

footer {
  padding-block: 2rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 720px) {
  .site-header {
    align-items: flex-start;
  }

  nav {
    flex-direction: column;
    gap: 0.55rem;
    text-align: right;
  }

  .hero {
    min-height: 72vh;
  }

  .content-section,
  .auth-panel {
    grid-template-columns: 1fr;
  }

  .content-section {
    gap: 2rem;
  }

  .skill-list {
    grid-template-columns: 1fr;
  }

  .community-heading,
  .member-panel,
  .message-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .community-intro,
  .auth-panel,
  .member-panel,
  .admin-panel,
  .form-status,
  .chat-shell {
    margin-left: 0;
  }

  .chat-message {
    max-width: 92%;
  }

  .message-actions > div {
    align-items: flex-start;
    flex-direction: column;
  }

  .message-actions > button,
  .account-form button,
  .member-panel button {
    width: 100%;
  }

  .image-preview-panel {
    flex-direction: column;
  }

  .admin-panel > header,
  .admin-user-row {
    align-items: stretch;
  }

  .admin-panel > header {
    flex-direction: column;
  }

  .admin-user-row {
    grid-template-columns: 1fr;
  }

  .admin-panel > header button,
  .admin-user-row button,
  .admin-user-actions {
    width: 100%;
  }

  .admin-user-actions {
    flex-direction: column;
  }
}