:root {
  --color-navy:   #0B1426;
  --color-blue:   #003DB5;
  --color-accent: #0055FF;

  --color-surface:    #0e1b32;
  --color-surface-2:  #13224099;
  --color-border:     rgba(0, 61, 181, 0.22);
  --color-border-hover: rgba(0, 85, 255, 0.45);

  --color-text:       #dde5f4;
  --color-text-muted: #5e7499;
  --color-text-dim:   #3d5278;

  --color-success:    #22c55e;
  --color-danger:     #f04646;

  --radius-lg: 20px;
  --radius:    12px;
  --radius-sm: 8px;

  --shadow-card: 0 32px 80px rgba(0, 0, 0, 0.55), 0 2px 0 rgba(255,255,255,0.03) inset;
  --shadow-btn:  0 4px 18px rgba(0, 85, 255, 0.4);
  --transition:  all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ── Reset ─────────────────────────────────────────── */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* ── Body / Layout ──────────────────────────────────── */
body {
  background-color: var(--color-navy);
  font-family: 'Inter', sans-serif;
  color: var(--color-text);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 28px 16px;
  background-image:
    radial-gradient(ellipse 60% 50% at 15% 10%, rgba(0, 85, 255, 0.09) 0%, transparent 100%),
    radial-gradient(ellipse 50% 40% at 85% 90%, rgba(0, 61, 181, 0.07) 0%, transparent 100%);
}

.app-wrapper {
  width: 100%;
  max-width: 560px;
}

/* ── Card ───────────────────────────────────────────── */
.card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-card);
  overflow: hidden;
}

/* ── Header ─────────────────────────────────────────── */
.app-header {
  padding: 32px 32px 24px;
  background:
    linear-gradient(135deg, rgba(0, 61, 181, 0.18) 0%, rgba(0, 85, 255, 0.08) 100%);
  border-bottom: 1px solid var(--color-border);
  position: relative;
  overflow: hidden;
}

.app-header::after {
  content: '';
  position: absolute;
  top: -60px;
  right: -60px;
  width: 260px;
  height: 260px;
  background: radial-gradient(circle, rgba(0, 85, 255, 0.12) 0%, transparent 65%);
  pointer-events: none;
}

.header-top {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 22px;
}

.header-icon {
  width: 42px;
  height: 42px;
  background: linear-gradient(135deg, var(--color-blue), var(--color-accent));
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  color: #fff;
  box-shadow: 0 4px 16px rgba(0, 85, 255, 0.45);
  flex-shrink: 0;
}

.app-header h1 {
  font-size: 1.45rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  color: #fff;
}

/* Progress bar */
.progress-section {
  display: flex;
  align-items: center;
  gap: 10px;
}

.progress-label,
.progress-count {
  font-size: 0.74rem;
  font-weight: 500;
  color: var(--color-text-muted);
  white-space: nowrap;
}

.progress-bar-wrap {
  flex: 1;
  height: 4px;
  background: rgba(255, 255, 255, 0.07);
  border-radius: 99px;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--color-blue), var(--color-accent));
  border-radius: 99px;
  transition: width 0.45s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ── Input Section ──────────────────────────────────── */
.input-section {
  padding: 22px 28px;
  border-bottom: 1px solid var(--color-border);
}

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

.todo-input {
  flex: 1;
  background: var(--color-navy);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius);
  padding: 11px 16px;
  color: var(--color-text);
  font-family: inherit;
  font-size: 0.88rem;
  outline: none;
  transition: var(--transition);
}

.todo-input::placeholder {
  color: var(--color-text-dim);
}

.todo-input:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(0, 85, 255, 0.14);
}

.todo-button {
  width: 44px;
  height: 44px;
  background: linear-gradient(135deg, var(--color-blue), var(--color-accent));
  border: none;
  border-radius: var(--radius);
  color: #fff;
  font-size: 0.95rem;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  box-shadow: var(--shadow-btn);
}

.todo-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 85, 255, 0.55);
}

.todo-button:active {
  transform: translateY(0);
}

/* ── Filter Section ─────────────────────────────────── */
.filter-section {
  padding: 14px 28px;
  display: flex;
  gap: 6px;
  border-bottom: 1px solid var(--color-border);
}

.filter-btn {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 6px 14px;
  border-radius: 99px;
  border: 1.5px solid transparent;
  background: transparent;
  color: var(--color-text-muted);
  font-family: inherit;
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.filter-btn:hover {
  color: var(--color-text);
  background: rgba(255, 255, 255, 0.04);
}

.filter-btn.active {
  background: rgba(0, 85, 255, 0.12);
  border-color: rgba(0, 85, 255, 0.35);
  color: #7aabff;
}

.filter-badge {
  background: rgba(255, 255, 255, 0.07);
  color: var(--color-text-muted);
  font-size: 0.68rem;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: 99px;
  min-width: 18px;
  text-align: center;
  transition: var(--transition);
}

.filter-btn.active .filter-badge {
  background: rgba(0, 85, 255, 0.25);
  color: #7aabff;
}

/* ── Todo Container ─────────────────────────────────── */
.todo-container {
  padding: 16px 24px 24px;
  min-height: 160px;
  max-height: 420px;
  overflow-y: auto;
}

.todo-container::-webkit-scrollbar {
  width: 3px;
}
.todo-container::-webkit-scrollbar-track {
  background: transparent;
}
.todo-container::-webkit-scrollbar-thumb {
  background: rgba(0, 61, 181, 0.35);
  border-radius: 99px;
}

.todo-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

/* ── Todo Item ──────────────────────────────────────── */
.todo {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 13px 14px;
  background: rgba(11, 20, 38, 0.7);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: var(--transition);
  animation: slideIn 0.22s ease both;
  position: relative;
}

.todo::before {
  content: '';
  position: absolute;
  left: 0;
  top: 20%;
  bottom: 20%;
  width: 3px;
  background: linear-gradient(180deg, var(--color-blue), var(--color-accent));
  border-radius: 0 3px 3px 0;
  opacity: 0;
  transition: var(--transition);
}

.todo:hover {
  border-color: var(--color-border-hover);
  background: rgba(11, 20, 38, 0.9);
}

.todo:hover::before {
  opacity: 1;
}

.todo.completed {
  opacity: 0.55;
}

.todo-item {
  flex: 1;
  font-size: 0.875rem;
  font-weight: 400;
  color: var(--color-text);
  line-height: 1.45;
  word-break: break-word;
  transition: var(--transition);
}

.todo.completed .todo-item {
  text-decoration: line-through;
  color: var(--color-text-muted);
}

/* ── Action Buttons ─────────────────────────────────── */
.complete-btn,
.trash-btn {
  width: 30px;
  height: 30px;
  border: 1.5px solid transparent;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.72rem;
  transition: var(--transition);
  flex-shrink: 0;
}

.complete-btn {
  background: rgba(34, 197, 94, 0.08);
  border-color: rgba(34, 197, 94, 0.2);
  color: #4ade80;
}

.complete-btn:hover {
  background: rgba(34, 197, 94, 0.18);
  border-color: rgba(34, 197, 94, 0.45);
  transform: scale(1.05);
}

.todo.completed .complete-btn {
  background: rgba(34, 197, 94, 0.15);
  border-color: rgba(34, 197, 94, 0.4);
  color: #4ade80;
}

.trash-btn {
  background: rgba(240, 70, 70, 0.06);
  border-color: rgba(240, 70, 70, 0.12);
  color: var(--color-danger);
  opacity: 0;
  transform: scale(0.85);
}

.todo:hover .trash-btn {
  opacity: 1;
  transform: scale(1);
}

.trash-btn:hover {
  background: rgba(240, 70, 70, 0.18);
  border-color: rgba(240, 70, 70, 0.4);
  transform: scale(1.05);
}

/* ── Empty State ────────────────────────────────────── */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 44px 20px;
  gap: 12px;
  text-align: center;
}

.empty-state i {
  font-size: 2.2rem;
  color: var(--color-text-dim);
}

.empty-state p {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

.empty-state.hidden {
  display: none;
}

/* ── Animations ─────────────────────────────────────── */
@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateY(-6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slideOut {
  to {
    opacity: 0;
    transform: translateX(16px) scale(0.96);
  }
}

/* ── Responsive ─────────────────────────────────────── */
@media (max-width: 480px) {
  body {
    padding: 16px 12px;
    align-items: flex-start;
  }

  .app-header {
    padding: 24px 20px 18px;
  }

  .input-section {
    padding: 16px 20px;
  }

  .filter-section {
    padding: 12px 20px;
  }

  .todo-container {
    padding: 12px 16px 20px;
  }

  .app-header h1 {
    font-size: 1.2rem;
  }
}