:root {
  --bg: #f8f9fa;
  --card: #ffffff;
  --primary: #2c7a7b;
  --accent: #68d391;
  --danger: #e53e3e;
  --text: #333;
  --shadow: rgba(0, 0, 0, 0.1);
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #181a1b;
    --card: #242526;
    --text: #f1f1f1;
    --shadow: rgba(0, 0, 0, 0.4);
  }
}

body {
  margin: 0;
  font-family: system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  padding-bottom: 5em;
}

header {
  background: var(--bg);
  color: var(--text);
  text-align: center;
  padding: 1em;
  font-size: 1.8em;
  font-weight: bold;
  box-shadow: 0 1px 8px var(--shadow); /* subtle divider */
}

#task-list {
  max-width: 600px;
  margin: auto;
  padding: 1em;
  display: flex;
  flex-direction: column;
  gap: 1em;
}

.task {
  background: var(--card);
  border-radius: 12px;
  padding: 1em;
  box-shadow: 0 2px 6px var(--shadow);
  transition: transform 0.2s ease, background 0.3s ease;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.task.done {
  background: var(--accent);
  color: black;
}

.task-name {
  font-size: 1.1em;
  flex-grow: 1;
}

.streak {
  font-size: 0.9em;
  margin-left: 0.5em;
}

.progress-bar {
  text-align: center;
  font-size: 1em;
  margin: 1em 0;
}

.fab {
  position: fixed;
  bottom: 1em;
  right: 1em;
  width: 60px;
  height: 60px;
  background: var(--primary);
  color: white;
  font-size: 2em;
  border: none;
  border-radius: 50%;
  box-shadow: 0 4px 8px var(--shadow);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.3s ease;
}
.fab:hover { background: #319795; }

dialog::backdrop { background: rgba(0, 0, 0, 0.4); }

dialog {
  position: relative;
  border: none;
  border-radius: 12px;
  padding: 1.5em;
  width: 90%;
  max-width: 400px;
  background: var(--card);
  box-shadow: 0 8px 16px var(--shadow);
  font-size: 1em;
}

.dialog-buttons {
  display: flex;
  justify-content: space-between;
  gap: 1em;
}
.dialog-buttons button { flex: 1; }

#add-form {
  display: flex;
  flex-direction: column;
  gap: 1em;
}
#add-form input {
  font-size: 1em;
  padding: 0.75em;
  border-radius: 6px;
  border: 1px solid #ccc;
}
#add-form button {
  font-size: 1em;
  padding: 0.75em;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.2s ease;
}
#add-form button:hover { background: #319795; }

#close-dialog {
  position: absolute;
  top: 0.5em;
  right: 0.5em;
  background: none;
  border: none;
  font-size: 1.5em;
  color: var(--text);
  cursor: pointer;
}

/* Shake animation */
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-8px); }
  40%, 80% { transform: translateX(8px); }
}
.shake { animation: shake 0.4s ease; }

/* Toast styles */
#toast {
  position: fixed;
  bottom: 2em;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary);
  color: white;
  padding: 0.8em 1.2em;
  border-radius: 8px;
  font-size: 0.95em;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
  z-index: 1000;
}
#toast.show { opacity: 1; }

.chain-icon { color: #444; transition: color 0.2s ease; }
.task.done .chain-icon { color: white; }

.site-title { font-size: 2rem; font-weight: bold; }

#auth-buttons { position: absolute; right: 1rem; top: 1rem; }
#auth-buttons button {
  background: var(--primary);
  color: #fff;
  border: 0;
  padding: .45rem .8rem;
  border-radius: .45rem;
  font-size: .9rem;
  cursor: pointer;
  transition: filter .15s ease;
}
#auth-buttons button:hover { filter: brightness(0.95); }
#auth-buttons button[disabled] { opacity: .6; cursor: default; }

/* Spinner on buttons */
.btn-loading { position: relative; pointer-events: none; }
.btn-loading::after {
  content: "";
  position: absolute; right: .5rem; top: 50%; width: 14px; height: 14px;
  margin-top: -7px; border-radius: 50%;
  border: 2px solid currentColor; border-top-color: transparent;
  animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Sync indicator (bottom-right toastlet) */
.sync {
  position: fixed; right: 12px; bottom: 12px; z-index: 50;
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--shadow);
  border-radius: 10px;
  padding: .4rem .7rem;
  box-shadow: 0 6px 20px var(--shadow);
  opacity: 1; transform: translateY(0);
  transition: opacity .25s ease, transform .25s ease;
  font-size: .9rem;
}
.sync.hidden { opacity: 0; transform: translateY(8px); pointer-events: none; }

/* Install banner */
.install {
  position: fixed; left: 12px; right: 12px; bottom: 12px; z-index: 60;
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--shadow);
  border-radius: 12px;
  padding: .7rem .9rem;
  box-shadow: 0 10px 30px var(--shadow);
  display: flex; align-items: center; justify-content: space-between; gap: .75rem;
}
.install.hidden { display: none; }
.install .actions { display: flex; gap: .5rem; }
.btn { background: var(--primary); color: #fff; border: 0; padding: .45rem .8rem; border-radius: .45rem; }
.btn-ghost { background: transparent; color: var(--text); border: 1px solid var(--shadow); }