@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

:root {
  --primary-color: #336dec;
  --primary-light: #93baff;
  --primary-dark: #233a75;
  --secondary-color: #12b886;
  --secondary-light: #51efc1;
  --danger-color: #ff4b4b;
  --warning-color: #f59e0b;
  --surface: #ffffff;
  --surface-alt: #f8faff;
  --surface-card: rgba(255, 255, 255, 0.87);
  --outline: #e7eaf0;

  --text-main: #181826;
  --text-secondary: #556180;
  --shadow-lg: 0 8px 24px rgba(60,60,100,0.11), 0 1.5px 3px rgba(60,60,100,0.05);

  --transition: 0.18s cubic-bezier(.4,0,.2,1);
  --border-radius: 12px;
}

body.dark, .dark {
  --primary-color: #7faaf7;
  --primary-light: #3a75de;
  --primary-dark: #181946;
  --secondary-color: #12b886;
  --secondary-light: #51efc1;
  --danger-color: #ff5f56;
  --surface: #1c1f32;
  --surface-alt: #23263a;
  --surface-card: rgba(38, 43, 71, 0.97);
  --outline: #31395c;

  --text-main: #f3f6fa;
  --text-secondary: #98a4be;
  --shadow-lg: 0 4px 24px rgba(16,25,68,0.26);

  background: linear-gradient(135deg, #23263a 0%, #223661 100%);
  color: var(--text-main);
}


* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  font-family: 'Inter', 'Segoe UI', Arial, sans-serif;
  color: var(--text-main);
  background: linear-gradient(135deg, #e3f0ff 0%, #c2d3fd 100%);
  transition: background 0.6s, color 0.3s;
  min-height: 100vh;
  padding: 1rem;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
.container {
  background: var(--surface-card);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-lg);
  margin: 2rem auto 1rem;
  padding-bottom: 1.2rem;
  max-width: 800px;
  overflow: hidden;
  transition: background 0.5s;
}

/* ===== header and clock ===== */
.header {
  background: linear-gradient(120deg, var(--primary-color) 60%, var(--primary-light) 100%);
  color: #fff;
  padding: 2rem 1rem 1.5rem 1rem;
  text-align: center;
  border-radius: 0 0 var(--border-radius) var(--border-radius);
  position: relative;
  user-select: none;
}
.header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.digital-clock {
  font-size: 1.15rem;
  font-weight: 500;
  background: rgba(255, 255, 255, 0.15);
  padding: 0.7rem 1.5rem;
  border-radius: var(--border-radius);
  min-width: 200px;
  margin: 0 auto;
  max-width: 480px;
  user-select: none;
  box-shadow: 0 0 8px rgba(255,255,255,0.4);
}

/* ===== light dark toggle ===== */
.theme-toggle {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: var(--surface-card);
  color: var(--primary-color);
  border-radius: 50%;
  border: none;
  font-size: 1.5rem;
  width: 2.5rem;
  height: 2.5rem;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
  box-shadow: 0 4px 12px rgba(60, 100, 210, 0.05);
  user-select: none;
}
body.dark .theme-toggle, .dark .theme-toggle {
  background: #23263a;
  color: #ffcd47;
}
.theme-toggle:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* -------Task Input Section ----- */
.task-input-section {
  padding: 1.5rem;
  background: var(--surface-alt);
  border-bottom: 1px solid var(--outline);
}
.task-form {
  display: flex;
  gap: 1rem;
  max-width: 700px;
  margin: 0 auto;
}
.task-input {
  flex: 2;
  padding: 0.75rem 1rem;
  border: 2px solid var(--outline);
  border-radius: var(--border-radius);
  font-size: 1rem;
  background: var(--surface-alt);
  color: var(--text-main);
  transition: border 0.18s, color 0.18s, background 0.18s;
}
.task-input::placeholder {
  color: var(--text-secondary);
}
.task-input:focus {
  border-color: var(--primary-color);
  outline: none;
  background: var(--surface);
}
.category-select {
  flex: 1;
  padding: 0.75rem 1rem;
  border: 2px solid var(--outline);
  border-radius: var(--border-radius);
  font-size: 1rem;
  background: var(--surface-alt);
  color: var(--text-main);
  cursor: pointer;
  transition: border 0.18s, color 0.18s, background 0.18s;
}
.category-select:focus {
  border-color: var(--primary-color);
  outline: none;
  background: var(--surface);
}
.add-btn {
  background: linear-gradient(130deg, var(--primary-color), var(--secondary-color) 90%);
  color: #fff;
  border: none;
  padding: 0.75rem 1.25rem;
  border-radius: var(--border-radius);
  font-weight: 600;
  cursor: pointer;
  transition: filter 0.2s, background 0.18s;
  display: flex;
  align-items: center;
  gap: 0.3rem;
  min-width: 90px;
  justify-content: center;
  box-shadow: 0 1.5px 5px rgba(80, 100, 180, 0.06);
  user-select: none;
}
.add-btn:hover,
.control-btn:hover {
  filter: brightness(1.12);
}
.btn-text {
  user-select: none;
}

/* ===== Task Stats ===== */
.task-stats {
  display: flex;
  justify-content: space-around;
  padding: 1rem 1.2rem;
  background: var(--surface);
  border-bottom: 1px solid var(--outline);
}
.stats-item {
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  user-select: none;
}
.stats-item span:first-child {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--primary-color);
}
.stats-item span:last-child {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
}

/* ===== Task Controls with Filter ===== */
.task-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 2rem;
  background: var(--surface-alt);
  border-bottom: 1px solid var(--outline);
  justify-content: center;
  flex-wrap: wrap;
}
.control-btn {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: var(--border-radius);
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  font-size: 0.9rem;
  user-select: none;
}
.control-btn.secondary {
  background: var(--secondary-color);
  color: white;
  box-shadow: 0 2px 6px rgba(18,184,134,0.5);
}
.control-btn.danger {
  background: var(--danger-color);
  color: white;
  box-shadow: 0 2px 6px rgba(255,75,75,0.5);
}
.category-filter {
  padding: 0.5rem 1rem;
  border-radius: var(--border-radius);
  border: 2px solid var(--outline);
  font-size: 1rem;
  background: var(--surface);
  min-width: 180px;
  cursor: pointer;
  color: var(--text-main);
  user-select: none;
  transition: border 0.18s, color 0.18s, background 0.18s;
}
.category-filter:focus {
  border-color: var(--primary-color);
  outline: none;
}

@media (max-width: 480px) {
  .task-controls {
    flex-direction: column;
    gap: 0.75rem;
    padding: 1rem;
  }
  .category-filter {
    width: 100%;
    min-width: auto;
  }
  .control-btn {
    width: 100%;
    max-width: none;
  }
}

/* ===== Tasks List and Items ===== */
.tasks-section {
  min-height: 220px;
  padding: 1.2rem;
}
.tasks-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  max-height: 450px;
  overflow-y: auto;
  background: var(--surface-alt);
  border-radius: var(--border-radius);
  box-shadow: 0 2.5px 12px rgba(60, 100, 180, 0.06);
  padding-top: 0.4rem;
  padding-bottom: 0.4rem;
  user-select: none;
}
.task-item {
  background: var(--surface-card);
  border: 1.5px solid var(--outline);
  border-radius: var(--border-radius);
  margin-bottom: 0.5rem;
  transition: box-shadow 0.18s, background 0.2s;
  padding: 0.5rem 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  position: relative;
}
.task-item:hover {
  box-shadow: 0 1.5px 16px rgba(100, 170, 255, 0.09);
}
.task-item.completed {
  opacity: 0.7;
  background: var(--surface-alt);
}
.task-checkbox {
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 50%;
  border: 2px solid var(--secondary-color);
  color: #fff;
  background: var(--secondary-color);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition);
  flex-shrink: 0;
  font-size: 1.15rem;
  user-select: none;
}
.task-checkbox.checked {
  background: var(--secondary-color);
  border-color: var(--secondary-color);
  color: #fff;
}
.task-checkbox:hover {
  border-color: var(--secondary-light);
}

.task-text {
  flex: 1;
  font-size: 0.92rem;
  line-height: 1.3;
  cursor: pointer;
  padding: 0.20rem 0;
  border-radius: 4px;
  transition: var(--transition);
  word-break: break-word;
  user-select: text;
}
.task-text.completed {
  text-decoration: line-through;
  color: var(--text-secondary);
}
.task-input-edit {
  flex: 1;
  font-size: 0.93rem;
  padding: 0.35rem 0.5rem;
  border: 2px solid var(--primary-color);
  border-radius: 4px;
  background: var(--surface);
  color: var(--text-main);
  user-select: text;
}
.task-input-edit:focus {
  outline: none;
  border-color: var(--secondary-color);
}

.task-category {
  color: #fff;
  background: linear-gradient(90deg, var(--primary-light), var(--secondary-color) 85%);
  border-radius: 16px;
  margin-left: 0.5rem;
  padding: 0.1rem 0.65rem;
  font-size: 0.74rem;
  letter-spacing: 0.01em;
  box-shadow: 0 1px 6px rgba(60, 128, 220, 0.05);
  user-select: none;
  white-space: nowrap;
}

.task-actions {
  display: flex;
  gap: 0.3rem;
  opacity: 0;
  transition: var(--transition);
}
.task-item:hover .task-actions {
  opacity: 1;
}
.task-btn {
  padding: 0.37rem;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: var(--transition);
  width: 1.75rem;
  height: 1.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.87rem;
  user-select: none;
}
.task-btn.edit {
  background: var(--warning-color);
  color: #fff;
  box-shadow: 0 2px 6px rgba(245, 154, 11, 0.5);
}
.task-btn.delete {
  background: var(--danger-color);
  color: #fff;
  box-shadow: 0 2px 6px rgba(255, 75, 75, 0.5);
}
.task-btn:hover {
  transform: scale(1.09);
}

/* ===== Empty State ===== */
.empty-state {
  text-align: center;
  padding: 2rem 1rem;
  color: var(--text-secondary);
  font-style: italic;
  user-select: none;
}
.empty-state p {
  font-size: 1.075rem;
  margin-bottom: 0.5rem;
}

/* ===== Footer ===== */
.footer {
  text-align: center;
  padding: 1.1rem;
  background: none;
  color: var(--text-secondary);
  border-top: 1.5px solid var(--outline);
  border-radius: 0 0 var(--border-radius) var(--border-radius);
  user-select: none;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  body {
    padding: 0.5rem;
  }
  .header h1 {
    font-size: 2rem;
  }
  .task-form {
    flex-direction: column;
    gap: 0.7rem;
  }
  .add-btn,
  .task-input,
  .category-select {
    width: 100%;
  }
  .container {
    max-width: 98vw;
  }
  .task-stats,
  .task-controls {
    padding-left: 0.3rem;
    padding-right: 0.3rem;
  }
  .tasks-list {
    gap: 0.3rem;
  }
  .task-category {
    margin-left: 0;
    margin-top: 0.15rem;
  }
  .task-actions {
    opacity: 1;
  }
}

@media (max-width: 480px) {
  .header {
    padding: 1rem;
  }
  .task-input-section,
  .tasks-section {
    padding: 1rem 0.3rem;
  }
  .task-stats {
    padding: 0.7rem 0.1rem;
  }
  .task-item {
    flex-wrap: wrap;
    gap: 0.3rem;
  }
  .task-category {
    margin-left: 0;
    margin-top: 0.18rem;
    order: 2;
    width: 100%;
    text-align: left;
  }
  .footer {
    padding: 0.6rem;
  }
}

/* ===== Scrollbar ===== */
.tasks-list::-webkit-scrollbar {
  width: 6px;
}
.tasks-list::-webkit-scrollbar-track {
  background: var(--surface-alt);
  border-radius: 3px;
}
.tasks-list::-webkit-scrollbar-thumb {
  background: var(--outline);
  border-radius: 3px;
}
.tasks-list::-webkit-scrollbar-thumb:hover {
  background: var(--text-secondary);
}