:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface-2: #1c2229;
  --border: #2a313c;
  --text: #e6edf3;
  --text-dim: #8b949e;
  --accent: #58a6ff;
  --accent-dim: #1f6feb33;
  --danger: #f85149;
  --success: #3fb950;

  --node: #83cd29;
  --aspnet: #9b6ef3;
  --django: #1f8b4c;
  --spring: #6db33f;

  --font-ui: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --font-mono: "SF Mono", "Consolas", "Liberation Mono", Menlo, monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-ui);
  min-height: 100vh;
}

body {
  background-image:
    radial-gradient(circle at 15% 0%, rgba(88,166,255,0.06), transparent 40%),
    radial-gradient(circle at 85% 15%, rgba(131,205,41,0.04), transparent 35%);
}

.app {
  max-width: 720px;
  margin: 0 auto;
  padding: 32px 20px 60px;
}

/* ---------- Topbar ---------- */
.topbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-mark {
  font-size: 22px;
  color: var(--accent);
}

.brand h1 {
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0;
}

.stack-switcher {
  display: flex;
  gap: 6px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 4px;
}

.stack-tab {
  display: flex;
  align-items: center;
  gap: 6px;
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-family: var(--font-ui);
  font-size: 12.5px;
  font-weight: 500;
  padding: 7px 10px;
  border-radius: 7px;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
}

.stack-tab:not(.is-locked):hover {
  background: var(--surface-2);
  color: var(--text);
}

.stack-tab.is-active {
  background: var(--accent-dim);
  color: var(--accent);
}

.stack-tab.is-locked {
  cursor: not-allowed;
  opacity: 0.45;
}

.stack-tab em {
  font-style: normal;
  font-size: 10px;
  color: var(--text-dim);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 4px;
  margin-left: 2px;
}

.dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  flex-shrink: 0;
}
.dot-node { background: var(--node); }
.dot-aspnet { background: var(--aspnet); }
.dot-django { background: var(--django); }
.dot-spring { background: var(--spring); }

/* ---------- Connection bar ---------- */
.connection-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12.5px;
  color: var(--text-dim);
  border: 1px solid var(--border);
  background: var(--surface);
  border-radius: 8px;
  padding: 8px 12px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.connection-bar code {
  font-family: var(--font-mono);
  color: var(--text);
  font-size: 12px;
}

.conn-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--text-dim);
  flex-shrink: 0;
}
.conn-dot.is-ok { background: var(--success); }
.conn-dot.is-down { background: var(--danger); }

.conn-status {
  margin-left: auto;
}

.link-btn {
  background: none;
  border: none;
  color: var(--accent);
  cursor: pointer;
  font-size: 12px;
  padding: 0;
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ---------- Cards ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px;
}

.is-hidden { display: none !important; }

/* Auth */
.tabs {
  display: flex;
  gap: 4px;
  margin-bottom: 18px;
  border-bottom: 1px solid var(--border);
}

.tab-btn {
  background: none;
  border: none;
  color: var(--text-dim);
  font-family: var(--font-ui);
  font-size: 13.5px;
  font-weight: 500;
  padding: 8px 4px;
  margin-right: 18px;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transform: translateY(1px);
}

.tab-btn.is-active {
  color: var(--text);
  border-bottom-color: var(--accent);
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.auth-form label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 12.5px;
  color: var(--text-dim);
}

input[type="text"],
input[type="email"],
input[type="password"] {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 7px;
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 14px;
  padding: 9px 11px;
  outline: none;
  transition: border-color 0.15s ease;
}

input:focus-visible {
  border-color: var(--accent);
}

.primary-btn {
  background: var(--accent);
  border: none;
  color: #04121f;
  font-family: var(--font-ui);
  font-size: 13.5px;
  font-weight: 600;
  padding: 10px 16px;
  border-radius: 7px;
  cursor: pointer;
  align-self: flex-start;
  transition: filter 0.15s ease;
}
.primary-btn:hover { filter: brightness(1.1); }
.primary-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.ghost-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-dim);
  font-size: 12.5px;
  padding: 7px 12px;
  border-radius: 7px;
  cursor: pointer;
}
.ghost-btn:hover { color: var(--text); border-color: var(--text-dim); }

.form-error {
  color: var(--danger);
  font-size: 12.5px;
  margin: 0;
  min-height: 1em;
}

/* Tasks */
.task-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 18px;
}

.eyebrow {
  display: block;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  margin-bottom: 2px;
}

.new-task-form {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}

.new-task-form input[name="title"] { flex: 1 1 160px; }
.new-task-form input[name="description"] { flex: 1 1 160px; }

.task-list {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.task-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px 4px;
  border-top: 1px solid var(--border);
}

.task-check {
  display: flex;
  align-items: center;
  padding-top: 2px;
  cursor: pointer;
}
.task-check input { display: none; }
.checkmark {
  width: 16px;
  height: 16px;
  border: 1.5px solid var(--border);
  border-radius: 4px;
  display: block;
  position: relative;
  transition: all 0.15s ease;
}
.task-check input:checked + .checkmark {
  background: var(--success);
  border-color: var(--success);
}
.task-check input:checked + .checkmark::after {
  content: "";
  position: absolute;
  left: 4px;
  top: 1px;
  width: 4px;
  height: 8px;
  border: solid #04121f;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.task-body {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.task-title-input {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 14px;
  padding: 2px 4px;
  border-radius: 5px;
  width: 100%;
}

.task-item.is-done .task-title-input { color: var(--text-dim); text-decoration: line-through; }

.task-title-input[readonly] {
  cursor: default;
}
.task-title-input:not([readonly]) {
  background: var(--surface-2);
  border-color: var(--border);
}

.task-meta {
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--text-dim);
  opacity: 0.7;
}

.task-actions {
  display: flex;
  gap: 4px;
  flex-shrink: 0;
}

.icon-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-dim);
  font-size: 11.5px;
  padding: 5px 9px;
  border-radius: 6px;
  cursor: pointer;
}
.icon-btn:hover { color: var(--text); border-color: var(--text-dim); }
.task-delete:hover { color: var(--danger); border-color: var(--danger); }
.task-save:hover { color: var(--success); border-color: var(--success); }

.empty-state {
  color: var(--text-dim);
  font-size: 13px;
  text-align: center;
  padding: 24px 0 4px;
}

.footer {
  text-align: center;
  color: var(--text-dim);
  font-size: 12px;
  margin-top: 32px;
}

@media (max-width: 480px) {
  .stack-tab span:not(.dot), .stack-tab em { display: none; }
  .conn-status { margin-left: 0; width: 100%; }
}