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

:root {
    --bg-base: #0d0f1a;
    --bg-card: rgba(255, 255, 255, 0.05);
    --border-glass: rgba(255, 255, 255, 0.1);
    --accent: #7c5cfc;
    --accent-glow: rgba(124, 92, 252, 0.4);
    --accent-hover: #9b7eff;
    --danger: #ff5e7d;
    --success: #3dd68c;
    --text-primary: #eef0ff;
    --text-muted: #8890b0;
    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;
    --transition: 0.25s ease;
}

/* ---------- Reset ---------- */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

/* ---------- Base ---------- */
body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-base);
    background-image:
        radial-gradient(ellipse 80% 50% at 50% -10%, rgba(124, 92, 252, 0.18), transparent),
        radial-gradient(ellipse 60% 40% at 80% 90%, rgba(61, 214, 140, 0.08), transparent);
    min-height: 100vh;
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 24px 16px;
    overflow-x: hidden;
}

/* ---------- Layout wrapper ---------- */
.container,
.todo-input,
.search,
.filters,
section,
footer {
    width: 100%;
    max-width: 560px;
}

/* ---------- Header ---------- */
.container {
    text-align: center;
    margin-bottom: 32px;
}

.container header h1 {
    font-size: clamp(1.8rem, 5vw, 2.6rem);
    font-weight: 700;
    letter-spacing: -0.5px;
    background: linear-gradient(120deg, #c4b5fd, #7c5cfc, #3dd68c);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.container header p {
    margin-top: 6px;
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 300;
    letter-spacing: 0.3px;
}

/* ---------- Glass card ---------- */
.todo-input,
.search,
.filters,
section {
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 16px;
    margin-bottom: 12px;
}

/* ---------- Add Task ---------- */
.todo-input {
    display: flex;
    align-items: center;
    gap: 10px;
}

.todo-input input[type="text"] {
    flex: 1;
    min-width: 0;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    font-size: 0.92rem;
    color: var(--text-primary);
    outline: none;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.todo-input input[type="text"]::placeholder {
    color: var(--text-muted);
}

.todo-input input[type="text"]:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

#addBtn {
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: var(--radius-sm);
    padding: 10px 20px;
    font-size: 0.88rem;
    font-weight: 600;
    cursor: pointer;
    white-space: nowrap;
    flex-shrink: 0;
    transition: background var(--transition), box-shadow var(--transition), transform var(--transition);
}

#addBtn:hover {
    background: var(--accent-hover);
    box-shadow: 0 4px 18px var(--accent-glow);
    transform: translateY(-1px);
}

#addBtn:active {
    transform: translateY(0);
}

/* ---------- Search ---------- */
.search input[type="text"] {
    width: 100%;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    font-size: 0.92rem;
    color: var(--text-primary);
    outline: none;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.search input[type="text"]::placeholder {
    color: var(--text-muted);
}

.search input[type="text"]:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

/* ---------- Filters ---------- */
.filters {
    display: flex;
    gap: 8px;
    padding: 10px 14px;
}

.filter-btn {
    flex: 1;
    min-width: 0;
    background: transparent;
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-sm);
    color: var(--text-muted);
    font-size: 0.85rem;
    font-weight: 500;
    padding: 8px 4px;
    cursor: pointer;
    text-align: center;
    white-space: nowrap;
    text-overflow: ellipsis;
    overflow: hidden;
    transition: all var(--transition);
}

.filter-btn:hover {
    color: var(--text-primary);
    border-color: rgba(255, 255, 255, 0.22);
}

.filter-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
    box-shadow: 0 2px 12px var(--accent-glow);
}

/* ---------- Task List ---------- */
section {
    padding: 8px;
}

#taskList {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 6px;
    min-height: 40px;
}

#taskList li {
    display: flex;
    align-items: center;
    gap: 12px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.07);
    border-radius: var(--radius-sm);
    padding: 12px 14px;
    transition: background var(--transition), transform var(--transition);
}

#taskList li:hover {
    background: rgba(255, 255, 255, 0.08);
    transform: translateX(3px);
}

#taskList li.completed {
    opacity: 0.5;
}

#taskList li.completed span {
    text-decoration: line-through;
    color: var(--text-muted);
}

/* Empty State Message from JS */
#taskList li.empty-msg {
    justify-content: center;
    color: var(--text-muted);
    background: transparent;
    border: 1px dashed var(--border-glass);
    pointer-events: none;
    transform: none !important;
    font-size: 0.88rem;
    padding: 16px;
    text-align: center;
}

/* Checkbox */
#taskList li input[type="checkbox"] {
    appearance: none;
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border: 2px solid var(--border-glass);
    border-radius: 50%;
    flex-shrink: 0;
    cursor: pointer;
    transition: background var(--transition), border-color var(--transition);
    position: relative;
}

#taskList li input[type="checkbox"]:checked {
    background: var(--success);
    border-color: var(--success);
}

#taskList li input[type="checkbox"]:checked::after {
    content: '\2713';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 11px;
    color: #0d0f1a;
    font-weight: 700;
}

/* Task text */
#taskList li span {
    flex: 1;
    font-size: 0.92rem;
    font-weight: 400;
    color: var(--text-primary);
    word-break: break-word;
    overflow-wrap: anywhere;
    transition: color var(--transition);
}

/* Delete button */
#taskList li .delete-btn,
#taskList li button {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 1rem;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 6px;
    flex-shrink: 0;
    transition: color var(--transition), background var(--transition);
}

#taskList li .delete-btn:hover,
#taskList li button:hover {
    color: var(--danger);
    background: rgba(255, 94, 125, 0.12);
}

/* ---------- Footer ---------- */
footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 18px;
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    margin-top: 4px;
    width: 100%;
    max-width: 560px;
}

#taskCounter {
    font-size: 0.82rem;
    color: var(--text-muted);
    font-weight: 500;
    white-space: nowrap;
}

#clearCompleted {
    background: transparent;
    border: 1px solid rgba(255, 94, 125, 0.3);
    border-radius: var(--radius-sm);
    color: var(--danger);
    font-size: 0.82rem;
    font-weight: 500;
    padding: 6px 14px;
    cursor: pointer;
    white-space: nowrap;
    transition: all var(--transition);
}

#clearCompleted:hover {
    background: rgba(255, 94, 125, 0.12);
    border-color: var(--danger);
    box-shadow: 0 2px 10px rgba(255, 94, 125, 0.2);
}

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.12);
    border-radius: 99px;
}

/* ---------- Empty state ---------- */
#taskList:empty::after {
    content: '\2726  No tasks yet. Add one above!';
    display: block;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.88rem;
    padding: 20px 0;
    letter-spacing: 0.3px;
}

/* ---------- Responsive — Tablet (≤600px) ---------- */
@media (max-width: 600px) {
    body {
        padding: 24px 14px 40px;
    }

    .container {
        margin-bottom: 20px;
    }

    .container header h1 {
        font-size: clamp(1.6rem, 6vw, 2.2rem);
    }
}

/* ---------- Responsive — Mobile (≤480px) ---------- */
@media (max-width: 480px) {
    body {
        padding: 16px 12px 30px;
    }

    .todo-input {
        gap: 8px;
        padding: 12px;
    }

    .todo-input input[type="text"] {
        padding: 9px 12px;
        font-size: 0.88rem;
    }

    #addBtn {
        padding: 9px 14px;
        font-size: 0.85rem;
    }

    .search {
        padding: 12px;
    }

    .search input[type="text"] {
        padding: 9px 12px;
        font-size: 0.88rem;
    }

    /* Filters */
    .filters {
        padding: 8px;
        gap: 6px;
    }

    .filter-btn {
        font-size: 0.8rem;
        padding: 7px 4px;
    }

    /* Task rows */
    #taskList li {
        padding: 10px 12px;
        gap: 10px;
    }

    #taskList li span {
        font-size: 0.88rem;
    }

    /* Footer */
    footer {
        padding: 12px 14px;
    }

    #taskCounter {
        font-size: 0.8rem;
    }

    #clearCompleted {
        padding: 6px 10px;
        font-size: 0.78rem;
    }
}

/* ---------- Responsive — Small phones (≤360px) ---------- */
@media (max-width: 360px) {
    body {
        padding: 12px 8px 24px;
    }

    .container header h1 {
        font-size: 1.4rem;
    }

    .container header p {
        font-size: 0.78rem;
    }

    .todo-input {
        padding: 10px;
        gap: 6px;
    }

    #addBtn {
        padding: 8px 10px;
        font-size: 0.8rem;
    }

    .filter-btn {
        font-size: 0.75rem;
        padding: 6px 2px;
    }

    #taskList li {
        padding: 8px 10px;
        gap: 8px;
    }

    #taskList li span {
        font-size: 0.82rem;
    }
}