/* ============================================
   HABIT TRACKER — CSS
   Theme: Black grid, dark glassmorphism
   Animations: High-level, smooth, satisfying
   ============================================ */

   *, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
  
  :root {
    --bg: #000000;
    --grid-line: rgba(255,255,255,0.05);
    --surface: rgba(0,0,0,0.5);
    --surface-hover: rgba(255,255,255,0.04);
    --border: rgba(255,255,255,0.1);
    --border-hover: rgba(255,255,255,0.2);
    --text: #ffffff;
    --text-secondary: rgba(255,255,255,0.5);
    --text-muted: rgba(255,255,255,0.25);
    --accent: rgba(255,255,255,0.15);
    --completed-bg: rgba(22,101,52,0.7);
    --completed-border: #1a4d2e;
    --completed-hover: rgba(22,101,52,0.9);
    --delete-hover: rgba(220,38,38,0.15);
    --delete-border-hover: rgba(220,38,38,0.4);
    --font: 'Outfit', sans-serif;
    --radius: 12px;
    --shadow: 0 8px 32px rgba(0,0,0,0.6);
  }
  
  /* ---- BODY + GRID ---- */
  
  body {
    background-color: var(--bg);
    background-image:
      linear-gradient(var(--grid-line) 1px, transparent 1px),
      linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
    background-size: 40px 40px;
    display: flex;
    flex-direction: column;
    font-family: var(--font);
    min-height: 100vh;
    padding-bottom: 80px;
    overflow-x: hidden;
  }
  
  /* ---- HEADING ---- */
  
  h1 {
    text-align: center;
    color: var(--text);
    font-family: var(--font);
    font-size: clamp(1.8rem, 4vw, 2.6rem);
    font-weight: 700;
    letter-spacing: -0.03em;
    margin: 48px 0 28px;
    animation: fadeDown 0.6s cubic-bezier(0.22, 1, 0.36, 1) both;
  }
  
  h1::after {
    content: '';
    display: block;
    width: 40px;
    height: 2px;
    background: rgba(255,255,255,0.3);
    margin: 10px auto 0;
    border-radius: 99px;
    animation: growBar 0.8s 0.3s cubic-bezier(0.22, 1, 0.36, 1) both;
  }
  
  @keyframes growBar {
    from { transform: scaleX(0); opacity: 0; }
    to   { transform: scaleX(1); opacity: 1; }
  }
  
  @keyframes fadeDown {
    from { opacity: 0; transform: translateY(-20px); }
    to   { opacity: 1; transform: translateY(0); }
  }
  
  @keyframes fadeUp {
    from { opacity: 0; transform: translateY(20px); }
    to   { opacity: 1; transform: translateY(0); }
  }
  
  @keyframes cardIn {
    from { opacity: 0; transform: translateY(16px) scale(0.98); }
    to   { opacity: 1; transform: translateY(0) scale(1); }
  }
  
  /* ---- INPUT ROW ---- */
  
  .input-row {
    display: flex;
    gap: 6px;
    width: 70%;
    align-self: center;
    animation: fadeDown 0.6s 0.1s cubic-bezier(0.22, 1, 0.36, 1) both;
  }
  
  .input-row > * {
    flex: 1;
  }
  
  input {
    background: var(--surface);
    border: 1px solid var(--border);
    padding: 12px;
    border-radius: var(--radius);
    outline: none;
    font-family: var(--font);
    color: var(--text);
    font-size: 1.2rem;
    transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.15s ease;
  }
  
  input::placeholder {
    color: var(--text-muted);
  }
  
  input:focus {
    border-color: rgba(255,255,255,0.3);
    box-shadow: 0 0 0 3px rgba(255,255,255,0.05);
    transform: translateY(-1px);
  }
  
  /* ---- BUTTONS ---- */
  
  button {
    border: 1px solid var(--border);
    background: rgba(0,0,0,0.8);
    color: var(--text);
    font-family: var(--font);
    font-size: 1rem;
    font-weight: 600;
    padding: 12px;
    outline: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: border-color 0.2s ease, background 0.2s ease,
                transform 0.15s ease, box-shadow 0.2s ease;
    position: relative;
    overflow: hidden;
    white-space: nowrap;
  }
  
  button::after {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at center, rgba(255,255,255,0.1) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 0.25s ease;
    pointer-events: none;
  }
  
  button:hover {
    border-color: var(--border-hover);
    background: rgba(255,255,255,0.06);
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(0,0,0,0.4);
  }
  
  button:hover::after {
    opacity: 1;
  }
  
  button:active {
    transform: scale(0.97) !important;
    box-shadow: none !important;
  }
  
  /* ---- WEEK NAV ---- */
  
  .week-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 70%;
    align-self: center;
    gap: 12px;
    margin: 10px 0 0;
    animation: fadeDown 0.6s 0.15s cubic-bezier(0.22, 1, 0.36, 1) both;
  }
  
  #prevWeekBtn,
  #nextWeekBtn {
    font-size: 0.85rem;
    padding: 9px 16px;
    display: flex;
    align-items: center;
    gap: 7px;
    flex: 0 0 auto;
  }
  
  #weekLabel {
    flex: 1;
    text-align: center;
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-secondary);
    letter-spacing: 0.02em;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }
  
  /* ---- HABITS CONTAINER ---- */
  
  #habitsContainer {
    align-self: center;
    width: 70%;
    margin-top: 20px;
    animation: fadeUp 0.6s 0.2s cubic-bezier(0.22, 1, 0.36, 1) both;
  }
  
  /* ---- HABIT CARD ---- */
  
  .habit-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 12px;
    margin-bottom: 12px;
    font-family: var(--font);
    color: var(--text);
    width: 100%;
    transition: border-color 0.25s ease, box-shadow 0.25s ease, transform 0.25s ease;
    animation: cardIn 0.45s cubic-bezier(0.22, 1, 0.36, 1) both;
  }
  
  .habit-card:hover {
    border-color: var(--border-hover);
    box-shadow: 0 8px 32px rgba(0,0,0,0.5);
    transform: translateY(-2px);
  }
  
  /* Stagger */
  .habit-card:nth-child(1) { animation-delay: 0.00s; }
  .habit-card:nth-child(2) { animation-delay: 0.05s; }
  .habit-card:nth-child(3) { animation-delay: 0.10s; }
  .habit-card:nth-child(4) { animation-delay: 0.15s; }
  .habit-card:nth-child(5) { animation-delay: 0.20s; }
  .habit-card:nth-child(6) { animation-delay: 0.25s; }
  .habit-card:nth-child(7) { animation-delay: 0.30s; }
  .habit-card:nth-child(8) { animation-delay: 0.35s; }
  
  /* ---- HABIT TOP ---- */
  
  .habit-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
  }
  
  .habit-title-group {
    display: flex;
    align-items: center;
    gap: 10px;
  }
  
  .habit-top h3 {
    color: var(--text);
    font-size: 1rem;
    font-weight: 600;
    letter-spacing: -0.01em;
  }
  
  .streak-badge {
    font-size: 0.7rem;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 99px;
    background: rgba(255,255,255,0.07);
    border: 1px solid rgba(255,255,255,0.12);
    color: var(--text-secondary);
    letter-spacing: 0.02em;
    transition: background 0.2s ease, color 0.2s ease;
  }
  
  /* ---- DELETE BUTTON ---- */
  
  .deleteBtn {
    background: transparent;
    border: 1px solid transparent;
    cursor: pointer;
    color: var(--text-muted);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    font-size: 0.8rem;
    padding: 0;
    transition: color 0.2s ease, background 0.2s ease,
                border-color 0.2s ease, transform 0.15s ease;
  }
  
  .deleteBtn:hover {
    color: #f87171;
    background: var(--delete-hover);
    border-color: var(--delete-border-hover);
    transform: rotate(8deg) scale(1.1) !important;
    box-shadow: none !important;
  }
  
  /* ---- DAYS ROW ---- */
  
  .days-row {
    display: flex;
    gap: 10px;
    margin-top: 15px;
  }
  
  /* ---- DAY BOX ---- */
  
  .day-box {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 6px;
    text-align: center;
    flex: 1;
    cursor: pointer;
    transition: background 0.2s ease, border-color 0.2s ease,
                transform 0.18s cubic-bezier(0.34, 1.56, 0.64, 1),
                box-shadow 0.2s ease;
    user-select: none;
  }
  
  .day-box p {
    color: var(--text-secondary);
    font-size: 0.7rem;
    font-weight: 600;
    line-height: 1.4;
  }
  
  .day-box p:last-child {
    color: var(--text);
    font-size: 0.9rem;
    font-weight: 700;
  }
  
  .day-box:hover {
    background: var(--surface-hover);
    border-color: var(--border-hover);
    transform: translateY(-3px) scale(1.04);
    box-shadow: 0 6px 16px rgba(0,0,0,0.5);
  }
  
  .day-box:active {
    transform: scale(0.95) !important;
  }
  
  /* ---- COMPLETED ---- */
  
  .completed {
    background: var(--completed-bg);
    border: 1px solid var(--completed-border);
    animation: completePop 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
  }
  
  .completed p {
    color: rgba(255,255,255,0.7);
  }
  
  .completed p:last-child {
    color: #ffffff;
  }
  
  .completed:hover {
    background: var(--completed-hover);
    border-color: #22683e;
    transform: translateY(-3px) scale(1.04);
    box-shadow: 0 6px 20px rgba(22,101,52,0.4);
  }
  
  @keyframes completePop {
    0%   { transform: scale(0.85); opacity: 0.5; }
    60%  { transform: scale(1.1); }
    100% { transform: scale(1); opacity: 1; }
  }
  
  /* ---- TODAY ---- */
  
  .day-box.today {
    border-color: rgba(255,255,255,0.3);
  }
  
  .day-box.today p:last-child {
    color: #ffffff;
  }
  
  .day-box.today.completed {
    border-color: var(--completed-border);
  }
  
  /* ---- PAST WEEK (read-only) ---- */
  
  .day-box.past-week {
    cursor: default;
  }
  
  .day-box.past-week:hover {
    transform: none;
    box-shadow: none;
    background: var(--surface);
    border-color: var(--border);
  }
  
  .day-box.past-week.completed:hover {
    background: var(--completed-bg);
    border-color: var(--completed-border);
    box-shadow: none;
    transform: none;
  }
  
  /* ---- EMPTY STATE ---- */
  
  .empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-muted);
    animation: fadeUp 0.5s cubic-bezier(0.22, 1, 0.36, 1) both;
  }
  
  .empty-state i {
    font-size: 2.2rem;
    margin-bottom: 14px;
    display: block;
    opacity: 0.3;
  }
  
  .empty-state p {
    font-size: 0.9rem;
    font-weight: 500;
  }
  
  /* ---- SCROLLBAR ---- */
  
  ::-webkit-scrollbar { width: 6px; }
  ::-webkit-scrollbar-track { background: #000; }
  ::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.1); border-radius: 99px; }
  ::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.2); }
  
  /* ---- RESPONSIVE ---- */
  
  @media (max-width: 700px) {
    .input-row,
    .week-nav,
    #habitsContainer {
      width: 92%;
    }
  
    .input-row {
      flex-wrap: wrap;
    }
  
    .input-row > * {
      flex: 1 1 45%;
    }
  
    input {
      flex: 1 1 100% !important;
    }
  
    .week-nav {
      flex-wrap: wrap;
      gap: 8px;
    }
  
    #weekLabel {
      order: -1;
      flex: 1 1 100%;
    }
  
    .days-row {
      gap: 5px;
    }
  
    .day-box {
      padding: 5px 3px;
    }
  
    .day-box p {
      font-size: 0.58rem;
    }
  
    .day-box p:last-child {
      font-size: 0.78rem;
    }
  }