:root {
    /* Futuristic Color Palette */
    --bg-dark: #0a0b10;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.125);
    --accent-neon: #00f2ff; /* Cyber Blue */
    --accent-glow: rgba(0, 242, 255, 0.5);
    --text-main: #ffffff;
    --text-dim: #a0a0a0;
    --delete-red: #ff4d4d;
}

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

html {
    font-family: 'Inter', 'Segoe UI', system-ui, sans-serif;
    font-size: 16px;
    color: var(--text-main);
    background-color: var(--bg-dark);
}

body {
    min-height: 100vh;
    padding: 20px;
    /* Animated Gradient Background */
    background: radial-gradient(circle at top right, #1a1b25, #0a0b10);
    background-attachment: fixed;
    display: flex;
    flex-direction: column;
    align-items: center;
    overflow-x: hidden;
}

/* Floating Decorative Orbs for depth */
body::before {
    content: "";
    position: fixed;
    top: 20%;
    left: 10%;
    width: 300px;
    height: 300px;
    background: var(--accent-glow);
    filter: blur(120px);
    border-radius: 50%;
    z-index: -1;
    opacity: 0.3;
}

h1 {
    margin-top: 60px;
    margin-bottom: 30px;
    font-size: 3.5rem;
    font-weight: 900;
    letter-spacing: 6px;
    text-transform: uppercase;
    background: linear-gradient(to bottom, #fff, var(--accent-neon));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 0 10px var(--accent-glow));
}

h1::after {
    content: "";
    width: 100px;
    height: 4px;
    background: var(--accent-neon);
    display: block;
    margin: 10px auto 0;
    border-radius: 2px;
    box-shadow: 0 0 15px var(--accent-neon);
}

.wrapper {
    width: 100%;
    max-width: 600px;
    display: flex;
    flex-direction: column;
    gap: 25px;
    margin-bottom: 120px;
    z-index: 1;
}

/* Progress Bar Styles */
.progress-container {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 10px;
}

.progress-stats {
    display: flex;
    justify-content: space-between;
    margin-bottom: 10px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--accent-neon);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.progress-bar-bg {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    overflow: hidden;
}

#progress-fill {
    width: 0%; /* Managed by JS */
    height: 100%;
    background: linear-gradient(90deg, var(--accent-neon), #bc00ff);
    box-shadow: 0 0 15px var(--accent-glow);
    transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Filter Button Styles */
.filter-container {
    display: flex;
    gap: 10px;
    margin-bottom: 5px;
}

.filter-btn {
    flex: 1;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    padding: 10px;
    border-radius: 12px;
    color: var(--text-dim);
    cursor: pointer;
    font-weight: 700;
    font-size: 0.75rem;
    letter-spacing: 1px;
    transition: all 0.3s ease;
}

.filter-btn:hover {
    background: rgba(255, 255, 255, 0.1);
    color: #fff;
}

.filter-btn.active {
    background: var(--accent-neon);
    color: #000;
    border-color: var(--accent-neon);
    box-shadow: 0 0 15px var(--accent-glow);
}


/* Form Styles */
form {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

#todo-input {
    padding: 18px 25px;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    color: white;
    font-size: 1.1rem;
    transition: all 0.3s ease;
    outline: none;
}

#todo-input:focus {
    border-color: var(--accent-neon);
    box-shadow: 0 0 20px rgba(0, 242, 255, 0.2);
    background: rgba(255, 255, 255, 0.08);
}

#add-button {
    padding: 15px;
    border-radius: 16px;
    border: none;
    background: var(--accent-neon);
    color: #000;
    font-weight: 800;
    font-size: 18px;
    letter-spacing: 1px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--accent-glow);
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
}


/* Ensure the icon scales properly within the button */
#add-button svg {
    pointer-events: none; /* Prevents the icon from blocking hover clicks */
}
#add-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px var(--accent-glow);
    filter: brightness(1.1);
}

/* List Styles */
#todo-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.todo {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 10px 20px;
    display: flex;
    align-items: center;
    transition: transform 0.2s ease, background 0.3s ease;
    animation: fadeIn 0.4s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.todo:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(255, 255, 255, 0.2);
}

.todo #todo-text {
    padding: 15px;
    flex-grow: 1;
    font-weight: 400;
    color: var(--text-main);
    transition: 0.3s ease;
}

/* Custom Checkbox */
.custom-checkbox {
    border: 2px solid var(--accent-neon);
    border-radius: 8px; /* Squared futuristic look */
    height: 24px;
    width: 24px;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: 0.3s;
}

input[type="checkbox"]:checked ~ .custom-checkbox {
    background-color: var(--accent-neon);
    box-shadow: 0 0 10px var(--accent-neon);
}
input[type="checkbox"]:checked ~ .custom-checkbox svg{
    fill: var(--text-dim);
}

input[type="checkbox"]:checked ~ #todo-text {
    text-decoration: line-through;
    color: var(--text-dim);
    opacity: 0.6;
}

input[type="checkbox"]{
    display: none;
}


/* Delete Button */
#delete-button {
    background: none;
    border: none;
    padding: 8px;
    cursor: pointer;
    border-radius: 8px;
    transition: 0.2s;
}

#delete-button svg {
    fill: var(--text-dim);
}

#delete-button:hover {
    background: rgba(255, 77, 77, 0.1);
}

#delete-button:hover svg {
    fill: var(--delete-red);
    filter: drop-shadow(0 0 5px var(--delete-red));
}

/* Footer & Socials */
.footer {
    position: fixed;
    bottom: 0;
    width: 100%;
    padding: 20px;
    background: rgba(10, 11, 16, 0.8);
    backdrop-filter: blur(20px);
    border-top: 1px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    z-index: 1000;
}

.footer p {
    font-size: 0.8rem;
    color: var(--text-dim);
    letter-spacing: 1px;
}

.social-links {
    display: flex;
    gap: 20px;
}

.social-links a svg {
    fill: var(--text-dim);
    transition: 0.3s ease;
}

.social-links a:hover svg {
    fill: var(--accent-neon);
    transform: translateY(-3px);
    filter: drop-shadow(0 0 8px var(--accent-neon));
}

/* Responsiveness */
@media(max-width: 500px) {
    h1 { font-size: 2.2rem; }
    .wrapper { width: 95%; }
    .footer { padding: 15px; }
}