:root {
  --ink: #1a2a2e;
  --ink-soft: #3d555c;
  --muted: #6b8289;
  --paper: #f3f7f6;
  --paper-elevated: rgba(255, 255, 255, 0.78);
  --line: rgba(26, 42, 46, 0.1);
  --accent: #0d8f7b;
  --accent-deep: #0a6e5f;
  --done: #7a9096;
  --danger: #c45c4a;
  --shadow: 0 18px 50px rgba(20, 48, 52, 0.12);
  --radius: 18px;
  --font: "Outfit", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.45;
}

.bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(900px 520px at 12% -10%, rgba(13, 143, 123, 0.18), transparent 55%),
    radial-gradient(700px 480px at 92% 8%, rgba(196, 140, 74, 0.14), transparent 50%),
    linear-gradient(165deg, #eef5f3 0%, #f7f3ec 48%, #e8f0ef 100%);
}

.bg::after {
  content: "";
  position: absolute;
  inset: 0;
  opacity: 0.35;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120' viewBox='0 0 120 120'%3E%3Cpath fill='none' stroke='%231a2a2e' stroke-opacity='0.04' d='M0 60h120M60 0v120'/%3E%3C/svg%3E");
}

.app {
  width: min(640px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 2.25rem 0 3.5rem;
  animation: rise 0.55s ease-out both;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.brand-mark {
  margin: 0;
  font-size: clamp(2.4rem, 7vw, 3.2rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1;
}

.brand-sub {
  margin: 0.45rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.sync-row {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  margin-top: 0.35rem;
  flex-wrap: wrap;
}

.sync-status {
  margin: 0;
  font-size: 0.8rem;
  color: var(--muted);
  font-family: var(--mono);
}

.sync-status[data-kind="ok"] {
  color: var(--accent-deep);
}

.sync-status[data-kind="pending"] {
  color: var(--ink-soft);
}

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

.btn-sync {
  appearance: none;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.65);
  color: var(--ink-soft);
  font: inherit;
  font-size: 0.78rem;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  cursor: pointer;
}

.btn-sync:hover {
  color: var(--ink);
  border-color: rgba(13, 143, 123, 0.35);
}

.tab-switch,
.mode-switch {
  display: inline-flex;
  padding: 4px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.55);
  border: 1px solid var(--line);
  backdrop-filter: blur(8px);
}

.tab-btn,
.mode-btn {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--ink-soft);
  font: inherit;
  font-weight: 500;
  font-size: 0.92rem;
  padding: 0.45rem 0.95rem;
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}

.tab-btn:hover,
.mode-btn:hover {
  color: var(--ink);
}

.tab-btn[aria-selected="true"],
.mode-btn[aria-selected="true"] {
  background: var(--ink);
  color: #f5faf9;
}

.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.85rem;
  flex-wrap: wrap;
}

.btn-archive {
  appearance: none;
  border: 1px solid rgba(13, 143, 123, 0.35);
  border-radius: 999px;
  background: rgba(13, 143, 123, 0.08);
  color: var(--accent-deep);
  font: inherit;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.5rem 0.95rem;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease, transform 0.15s ease;
}

.btn-archive:hover:not(:disabled) {
  background: rgba(13, 143, 123, 0.16);
  border-color: rgba(13, 143, 123, 0.55);
}

.btn-archive:active:not(:disabled) {
  transform: translateY(1px);
}

.btn-archive:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.panel {
  background: var(--paper-elevated);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(14px);
  padding: 1rem 1.1rem 1.15rem;
  animation: panel-in 0.35s ease both;
}

@keyframes panel-in {
  from {
    opacity: 0.4;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.panel.hidden,
#todos-section.hidden,
#archive-section.hidden {
  display: none;
}

.todo-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-height: 4rem;
}

.todo-item {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: start;
  gap: 0.65rem;
  padding: 0.55rem 0.45rem;
  border-radius: 12px;
  transition: background 0.2s ease;
}

.todo-item:hover {
  background: rgba(13, 143, 123, 0.06);
}

.todo-item.is-done .todo-text {
  color: var(--done);
  text-decoration: line-through;
  text-decoration-thickness: 1.5px;
  text-decoration-color: rgba(122, 144, 150, 0.7);
}

.todo-item.archive-item {
  grid-template-columns: 1fr auto;
}

.todo-item.archive-item .todo-text {
  color: var(--ink);
  text-decoration: none;
}

.check {
  appearance: none;
  width: 1.2rem;
  height: 1.2rem;
  margin-top: 0.2rem;
  border: 2px solid rgba(26, 42, 46, 0.35);
  border-radius: 6px;
  background: #fff;
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: border-color 0.15s ease, background 0.15s ease, transform 0.15s ease;
}

.check:hover {
  border-color: var(--accent);
  transform: scale(1.04);
}

.check:checked {
  background: var(--accent);
  border-color: var(--accent);
}

.check:checked::after {
  content: "";
  width: 0.28rem;
  height: 0.5rem;
  border: solid #fff;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg) translate(-0.5px, -0.5px);
}

.todo-text {
  width: 100%;
  border: 0;
  background: transparent;
  font: inherit;
  font-size: 1.02rem;
  color: var(--ink);
  padding: 0.1rem 0;
  resize: none;
  outline: none;
  min-height: 1.5rem;
  line-height: 1.45;
}

.todo-text:focus {
  background: rgba(255, 255, 255, 0.55);
  border-radius: 8px;
  box-shadow: 0 0 0 2px rgba(13, 143, 123, 0.18);
  padding-inline: 0.35rem;
}

.btn-remove {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 1.15rem;
  line-height: 1;
  padding: 0.15rem 0.35rem;
  border-radius: 8px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s ease, color 0.15s ease, background 0.15s ease;
}

.todo-item:hover .btn-remove,
.todo-item:focus-within .btn-remove {
  opacity: 1;
}

.btn-remove:hover {
  color: var(--danger);
  background: rgba(196, 92, 74, 0.08);
}

.empty {
  margin: 0.75rem 0.35rem 1rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.add-form {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.55rem;
  margin-top: 0.85rem;
  padding-top: 0.85rem;
  border-top: 1px solid var(--line);
}

.add-form input {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.7);
  font: inherit;
  font-size: 0.98rem;
  padding: 0.7rem 0.85rem;
  color: var(--ink);
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.add-form input:focus {
  border-color: rgba(13, 143, 123, 0.45);
  box-shadow: 0 0 0 3px rgba(13, 143, 123, 0.12);
}

.btn-add {
  appearance: none;
  border: 0;
  border-radius: 12px;
  background: var(--accent);
  color: #f4fffc;
  font: inherit;
  font-weight: 600;
  padding: 0.7rem 1rem;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.15s ease;
}

.btn-add:hover {
  background: var(--accent-deep);
}

.btn-add:active {
  transform: translateY(1px);
}

.edit-hint {
  display: block;
  margin: 0.15rem 0.2rem 0.7rem;
  color: var(--muted);
  font-size: 0.88rem;
}

.edit-hint code {
  font-family: var(--mono);
  font-size: 0.82em;
  color: var(--ink-soft);
  background: rgba(26, 42, 46, 0.05);
  padding: 0.1rem 0.3rem;
  border-radius: 4px;
}

.edit-area {
  width: 100%;
  min-height: min(58vh, 420px);
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.72);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 0.92rem;
  line-height: 1.65;
  padding: 0.95rem 1rem;
  resize: vertical;
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.edit-area:focus {
  border-color: rgba(13, 143, 123, 0.45);
  box-shadow: 0 0 0 3px rgba(13, 143, 123, 0.12);
}

.archive-root {
  display: flex;
  flex-direction: column;
  gap: 1.15rem;
  min-height: 4rem;
}

.archive-day {
  border-top: 1px solid var(--line);
  padding-top: 0.85rem;
}

.archive-day:first-child {
  border-top: 0;
  padding-top: 0.15rem;
}

.archive-day-title {
  margin: 0 0.35rem 0.45rem;
  font-size: 0.88rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--ink-soft);
}

.archive-day-title span {
  color: var(--muted);
  font-weight: 500;
  margin-left: 0.35rem;
}

@media (max-width: 520px) {
  .header {
    flex-direction: column;
    align-items: flex-start;
  }

  .add-form {
    grid-template-columns: 1fr;
  }

  .toolbar {
    align-items: stretch;
  }

  .btn-archive {
    width: 100%;
  }
}