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

body {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: Arial, Helvetica, sans-serif;
    background-color: #f1f5f9;
    color: #0f172a;
}

main {
    width: 100%;
    padding: 20px;
}

.todo-app {
    max-width: 520px;
    margin: 0 auto;
    padding: 28px 22px;
    border-radius: 12px;
    background-color: #ffffff;
    border: 1px solid #dbe2ea;
    box-shadow: 0 8px 18px rgba(15, 23, 42, 0.08);
}

h1 {
    text-align: center;
    margin-bottom: 16px;
    font-size: 34px;
    color: #0f172a;
}

.todo-form {
    display: flex;
    gap: 10px;
    margin-bottom: 16px;
}

.todo-form input {
    flex: 1;
    padding: 11px 12px;
    border-radius: 8px;
    border: 1px solid #cbd5e1;
    background-color: #ffffff;
    color: #0f172a;
    outline: none;
}

.todo-form button {
    border: none;
    border-radius: 8px;
    padding: 11px 16px;
    font-weight: 700;
    cursor: pointer;
    background-color: #2563eb;
    color: #ffffff;
}

.todo-form button:hover {
    background-color: #1d4ed8;
}

#todoList {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.todo-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding: 10px 12px;
    border-radius: 8px;
    border: 1px solid #dbe2ea;
    background-color: #f8fafc;
}

.todo-text {
    flex: 1;
    word-break: break-word;
}

.todo-item.completed .todo-text {
    text-decoration: line-through;
    opacity: 0.55;
    color: #64748b;
}

.todo-actions {
    display: flex;
    gap: 8px;
}

.icon-btn {
    width: 30px;
    height: 30px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 700;
}

.complete-btn {
    background-color: #22c55e;
    color: #052e16;
}

.delete-btn {
    background-color: #ef4444;
    color: #fee2e2;
}