:root{
  --bg:#ffffff;
  --card:#ffffff;
  --text:#222;
  --accent:#00bcd4;
  --danger:#f44336;
  --success:#4caf50;
  --header-bg:linear-gradient(90deg,#00bcd4,#006064);
  --input-border:#ddd;
}

body.dark{
  --bg:#0b0b0b;
  --card:#111;
  --text:#f5f5f5;
  --accent:#ff2da0;
  --danger:#ff4d6d;
  --success:#3ddc97;
  --header-bg:linear-gradient(90deg,#ff2da0,#8e00ff);
  --input-border:#ff2da0;
}
.title{
  color: #ffff;
}
.subtitle{
  color: #ffff;
}
/* RESET */
*{margin:0;padding:0;box-sizing:border-box;}

body{
  font-family:'Segoe UI',sans-serif;
  background:linear-gradient(135deg,#e0f7fa,#80deea);
  min-height:100vh;
  display:flex;
  justify-content:center;
  align-items:center;
  padding:20px;
  color:var(--text);
  transition:.3s;
}

body.dark{ background:#000; color:var(--text); }

/* APP CARD */
.app-wrapper{ width:100%; max-width:600px; }

.todo-card{
  background:var(--card);
  border-radius:14px;
  box-shadow:0 20px 50px rgba(0,0,0,.4);
  overflow:hidden;
  transition:.3s;
}

/* HEADER */
.todo-header{
  display:flex;
  justify-content:space-between;
  align-items:center;
  background: var(--header-bg);
  padding: 1.5rem 2rem;
  border-radius: 12px 12px 0 0;
  transition: 0.3s;
  position: relative;
}

.header-center{
  display:flex;
  flex-direction: column;
  align-items: center;
  flex:1;
}

.todo-header .title{
  font-size:2rem;
  margin-bottom:0.3rem;
}

.todo-header .subtitle{
  font-size:0.9rem;
  opacity:0.9;
}

#themeToggle{
  background: rgba(255,255,255,0.2);
  border: none;
  color:white;
  font-size:1.2rem;
  padding:6px 12px;
  border-radius:6px;
  cursor:pointer;
  transition: background 0.2s;
}

#themeToggle:hover{ background: rgba(255,255,255,0.4); }

/* FORM */
.todo-form-section{ padding:1.5rem 2rem 0; }

.input-group{ display:flex; gap:10px; }

#taskInput{
  flex:1;
  padding:12px;
  border-radius:6px;
  border:2px solid var(--input-border);
  font-size:1rem;
  transition:0.3s;
  background:transparent;
  color:var(--text);
}

#taskInput:focus{
  border-color:var(--accent);
  outline:none;
  box-shadow:0 0 5px rgba(0,188,212,0.5);
}

body.dark #taskInput:focus{
  box-shadow:0 0 8px rgba(255,45,160,0.6);
}

#taskInput:hover{ border-color:var(--accent); }

/* Form Note */
.form-note {
  font-size: 0.85rem;
  color: #666;
  margin-top: 8px;
  display: block;
  min-height: 18px;
  transition: color .3s;
}

body.dark .form-note{ color: #ccc; }

/* BUTTON */
#taskSubmit{
  background:var(--accent);
  color:white;
  border:none;
  border-radius:6px;
  padding:10px 20px;
  cursor:pointer;
  transition:transform .2s, opacity .2s;
}

#taskSubmit:hover{ opacity:0.9; transform:translateY(-2px); }

/* STATS */
.todo-stats-section{
  padding:1rem 2rem;
  border-top:1px solid #eee;
  border-bottom:1px solid #eee;
  display:flex;
  justify-content:space-between;
  align-items:center;
}

.stats{
  display:flex;
  justify-content:space-between;
  align-items:center;
  width:100%;
}

.stat-item{
  display:flex;
  flex-direction:column;
  align-items:center;
}

.stat-value{
  font-size:1.5rem;
  font-weight:700;
  background: linear-gradient(90deg,#00bcd4,#006064);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  transition:.3s;
}

body.dark .stat-value{
  background: linear-gradient(90deg,#ff2da0,#ff5ecb);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.stat-label{ font-size:.85rem; color:var(--text); }

.btn-clear{
  background:var(--danger);
  color:white;
  border:none;
  border-radius:6px;
  padding:8px 16px;
  cursor:pointer;
  transition:.2s;
}

.btn-clear:hover{ opacity:0.9; }

/* TASK LIST */
.todo-list-section{ padding:1rem 2rem 2rem; }

.task-list{ display:flex; flex-direction:column; gap:12px; padding-top:10px; }

/* TASK ITEM */
.task-item{
  display:flex;
  justify-content:space-between;
  align-items:center;
  padding:14px;
  border-radius:8px;
  transition:.3s;
  border-left:6px solid var(--accent);
  margin-top:10px;
  background: #f1f1f1;
  opacity:0;
  transform: translateY(20px);
  animation: fadeSlide 0.4s forwards;
  box-shadow:0 4px 12px rgba(0,188,212,0.3);
}

body.dark .task-item{
  background:#111;
  box-shadow:0 0 15px rgba(255,45,160,0.6);
}

/* ANIMATION */
@keyframes fadeSlide{
  to{
    opacity:1;
    transform: translateY(0);
  }
}

/* HOVER */
.task-item:hover{
  transform:translateY(-4px);
  transition:.3s;
}

body:not(.dark) .task-item:hover{
  box-shadow:0 8px 20px rgba(0,188,212,0.5);
}

body.dark .task-item:hover{
  box-shadow:0 0 25px rgba(255,45,160,0.8);
}

/* TASK CONTENT */
.task-content{
  flex:1;
  display:flex;
  align-items:center;
  gap:8px;
  word-break:break-word;
}

.task-content.completed{ text-decoration:line-through; opacity:0.6; }

.task-actions{ display:flex; gap:6px; }

.task-btn{
  padding:6px 12px;
  border:none;
  border-radius:4px;
  cursor:pointer;
  font-size:.85rem;
  color:white;
}

.update-btn{ background:var(--success); }
.delete-btn{ background:var(--danger); }

/* FOOTER */
.footer{
  text-align:center;
  padding:1rem;
  font-size:.8rem;
  opacity:.7;
}

/* MODAL */
.modal{
  display:none;
  position:fixed;
  inset:0;
  background:rgba(0,0,0,0.5);
  justify-content:center;
  align-items:center;
  z-index:1000;
}

.modal-content{
  background:var(--card);
  padding:1.5rem 2rem;
  border-radius:8px;
  max-width:400px;
  width:90%;
  color:var(--text);
}

.modal-actions{
  display:flex;
  justify-content:flex-end;
  gap:10px;
  margin-top:1rem;
}

.btn-secondary{
  background:#757575;
  color:white;
  border:none;
  border-radius:4px;
  padding:8px 16px;
  cursor:pointer;
}

.btn-danger{
  background:var(--danger);
  color:white;
  border:none;
  border-radius:4px;
  padding:8px 16px;
  cursor:pointer;
}

.task-content input[type="checkbox"]{
  accent-color: var(--accent);
  width:18px;
  height:18px;
  cursor:pointer;
}
.task-content input[type="checkbox"]{
  accent-color: var(--accent);
  width:16px;
  height:16px;
  cursor:pointer;
}
.task-content.completed span,
.task-content.completed p{
  text-decoration: line-through;
  opacity:0.6;
}


/* RESPONSIVE */
@media(max-width:600px){
  .todo-header{
    flex-direction:column;
    align-items:center;
    gap:10px;
  }
  #themeToggle{ align-self:flex-end; }
  .todo-header h1{ font-size:1.6rem; }
  .input-group{ flex-direction:column; }
  #taskSubmit{ width:100%; }
  .task-item{ flex-direction:column; align-items:flex-start; gap:6px; }
  .task-actions{ align-self:flex-end; }
}