* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg: #081120;
  --card: rgba(255, 255, 255, 0.06);
  --card-strong: rgba(255, 255, 255, 0.1);
  --text: #ffffff;
  --muted: #cdd8ee;
  --accent: #ffd35a;
  --accent-dark: #101828;
  --border: rgba(255, 255, 255, 0.08);
  --input: rgba(255, 255, 255, 0.05);
  --danger: #ef4444;
  --shadow: 0 16px 32px rgba(0, 0, 0, 0.2);
}

body.light-mode {
  --bg: #f4f7fb;
  --card: rgba(8, 17, 32, 0.05);
  --card-strong: rgba(8, 17, 32, 0.08);
  --text: #0f172a;
  --muted: #475569;
  --accent: #2563eb;
  --accent-dark: #ffffff;
  --border: rgba(15, 23, 42, 0.08);
  --input: rgba(15, 23, 42, 0.04);
  --danger: #dc2626;
  --shadow: 0 14px 28px rgba(15, 23, 42, 0.08);
}

body {
  font-family: "Poppins", sans-serif;
  background: linear-gradient(135deg, var(--bg), #0c2d63);
  color: var(--text);
  min-height: 100vh;
  transition: 0.3s ease;
}

body.light-mode {
  background: linear-gradient(135deg, #eef4ff, #dbeafe);
}

.app-container {
  width: min(1200px, 92%);
  margin: 0 auto;
  padding: 32px 0 50px;
}

.top-bar {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: flex-start;
  margin-bottom: 28px;
}

.small-tag {
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 6px;
}

.top-bar h1 {
  font-size: 2.5rem;
  line-height: 1.2;
  margin-bottom: 8px;
}

.subtitle {
  color: var(--muted);
}

.theme-btn,
#addTaskBtn,
#saveEditBtn,
.secondary-btn,
.danger-btn {
  border: none;
  cursor: pointer;
  font-family: inherit;
  transition: 0.3s ease;
}

.theme-btn {
  background: var(--card);
  color: var(--text);
  padding: 14px 18px;
  border-radius: 14px;
  border: 1px solid var(--border);
}

.theme-btn:hover {
  transform: translateY(-2px);
}

.task-input-section,
.search-filter-bar,
.summary-card,
.task-column,
.modal-content {
  background: var(--card);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
}

.task-input-section {
  padding: 22px;
  border-radius: 22px;
  margin-bottom: 24px;
}

.input-group {
  display: grid;
  grid-template-columns: 1.6fr 1fr auto;
  gap: 14px;
}

input,
select,
textarea {
  width: 100%;
  padding: 15px 16px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--input);
  color: var(--text);
  outline: none;
  font-family: inherit;
  font-size: 1rem;
}

input::placeholder {
  color: var(--muted);
}

select {
  appearance: none;
}

#addTaskBtn,
#saveEditBtn {
  background: var(--accent);
  color: var(--accent-dark);
  padding: 15px 22px;
  border-radius: 14px;
  font-weight: 700;
}

#addTaskBtn:hover,
#saveEditBtn:hover {
  transform: translateY(-2px);
}

.message {
  min-height: 22px;
  margin-top: 10px;
  color: #86efac;
  font-size: 0.95rem;
}

.summary-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-bottom: 24px;
}

.summary-card {
  padding: 24px;
  border-radius: 20px;
  text-align: center;
}

.summary-card h3 {
  font-size: 2rem;
  color: var(--accent);
  margin-bottom: 4px;
}

.summary-card p {
  color: var(--muted);
}

.search-filter-bar {
  padding: 18px;
  border-radius: 20px;
  display: grid;
  grid-template-columns: 1.3fr 0.8fr auto;
  gap: 14px;
  margin-bottom: 24px;
}

.danger-btn {
  background: var(--danger);
  color: #fff;
  padding: 14px 18px;
  border-radius: 14px;
  font-weight: 600;
}

.tasks-wrapper {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.task-column {
  padding: 22px;
  border-radius: 22px;
  min-height: 420px;
}

.task-column h2 {
  margin-bottom: 16px;
  font-size: 1.4rem;
}

.task-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.task-item {
  background: var(--card-strong);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 18px;
  animation: fadeIn 0.3s ease;
}

.task-top {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  align-items: flex-start;
}

.task-title {
  font-size: 1.05rem;
  font-weight: 600;
  word-break: break-word;
}

.task-date {
  margin-top: 8px;
  color: var(--muted);
  font-size: 0.9rem;
}

.task-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 14px;
}

.action-btn {
  border: none;
  padding: 10px 14px;
  border-radius: 12px;
  cursor: pointer;
  font-family: inherit;
  font-weight: 600;
  transition: 0.3s ease;
}

.complete-btn {
  background: #22c55e;
  color: white;
}

.edit-btn {
  background: #3b82f6;
  color: white;
}

.delete-btn {
  background: #ef4444;
  color: white;
}

.undo-btn {
  background: #8b5cf6;
  color: white;
}

.action-btn:hover {
  transform: translateY(-2px);
}

.empty-state {
  color: var(--muted);
  text-align: center;
  padding: 24px 10px;
  border: 1px dashed var(--border);
  border-radius: 16px;
}

/* MODAL */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(2, 6, 23, 0.72);
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
  z-index: 1000;
}

.hidden {
  display: none;
}

.modal-content {
  width: min(500px, 100%);
  padding: 24px;
  border-radius: 22px;
}

.modal-content h2 {
  margin-bottom: 16px;
}

.modal-content input {
  margin-bottom: 14px;
}

.modal-buttons {
  display: flex;
  gap: 12px;
  justify-content: flex-end;
}

.secondary-btn {
  background: rgba(255, 255, 255, 0.12);
  color: var(--text);
  padding: 14px 18px;
  border-radius: 14px;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 900px) {
  .input-group,
  .search-filter-bar,
  .summary-cards,
  .tasks-wrapper {
    grid-template-columns: 1fr;
  }

  .top-bar {
    flex-direction: column;
    align-items: stretch;
  }

  .top-bar h1 {
    font-size: 2rem;
  }
}

@media (max-width: 520px) {
  .app-container {
    width: 94%;
  }

  .task-top {
    flex-direction: column;
  }

  .modal-buttons {
    flex-direction: column;
  }
}