:root {
    --bg: #0f172a;
    --card: #111827;
    --accent: #22c55e;
    --text: #e5e7eb;
    --muted: #9ca3af;
    --danger: #ef4444;
}

* {
    box-sizing: border-box;
    font-family: "Segoe UI", system-ui, sans-serif;
}

body {
    background: linear-gradient(135deg, #020617, #0f172a);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    background: var(--card);
    width: 360px;
    padding: 24px;
    border-radius: 14px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, .4);
}

h1 {
    text-align: center;
    margin-bottom: 18px;
    font-size: 22px;
}

.output {
    display: flex;
    margin-bottom: 12px;
}

.output input {
    flex: 1;
    padding: 10px;
    border: none;
    border-radius: 8px 0 0 8px;
    outline: none;
    font-size: 14px;
}

.output button {
    padding: 0 14px;
    background: var(--accent);
    border: none;
    border-radius: 0 8px 8px 0;
    cursor: pointer;
    font-weight: bold;
}

.row {
    display: flex;
    justify-content: space-between;
    margin: 10px 0;
    font-size: 14px;
}

input[type="range"] {
    width: 100%;
}

.checkboxes label {
    display: flex;
    justify-content: space-between;
    margin: 8px 0;
}

.strength {
    height: 6px;
    border-radius: 5px;
    background: #1f2933;
    overflow: hidden;
    margin-top: 8px;
}

.strength div {
    height: 100%;
    width: 0%;
    transition: 0.4s;
}

.generate {
    width: 100%;
    margin-top: 18px;
    padding: 12px;
    background: var(--accent);
    border: none;
    border-radius: 8px;
    font-size: 15px;
    cursor: pointer;
    font-weight: bold;
}

.error {
    color: var(--danger);
    font-size: 13px;
    margin-top: 8px;
    text-align: center;
}