/* ─── RESET & BASE ─── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

/* ─── FONTS ─── */
@import url('https://fonts.googleapis.com/css2?family=Space+Mono:wght@400;700&family=Syne:wght@400;600;800&display=swap');

/* ─── VARIABLES ─── */
:root {
    --bg:         #0a0c10;
    --surface:    #111318;
    --surface2:   #181c24;
    --border:     rgba(255,255,255,0.07);
    --accent:     #00e5a0;
    --accent2:    #00b8ff;
    --text:       #e8eaf0;
    --muted:      #5a6070;
    --danger:     #ff4d6d;
    --warn:       #ffb830;
    --radius:     18px;
    --radius-sm:  10px;
    --mono:       'Space Mono', monospace;
    --display:    'Syne', sans-serif;
    --transition: 0.22s cubic-bezier(.4,0,.2,1);
}

/* ─── BODY ─── */
body {
    background-color: var(--bg);
    font-family: var(--display);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
    color: var(--text);
}

/* ─── BACKGROUND EFFECTS ─── */
.bg-grid {
    position: fixed;
    inset: 0;
    background-image:
        linear-gradient(rgba(0,229,160,0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0,229,160,0.03) 1px, transparent 1px);
    background-size: 40px 40px;
    pointer-events: none;
    z-index: 0;
}

.bg-glow {
    position: fixed;
    top: -120px;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 600px;
    background: radial-gradient(ellipse at center,
        rgba(0,229,160,0.10) 0%,
        rgba(0,184,255,0.05) 40%,
        transparent 70%);
    pointer-events: none;
    z-index: 0;
}

/* ─── CARD ─── */
#password-generator {
    position: relative;
    z-index: 1;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px 28px 28px;
    width: 460px;
    box-shadow:
        0 0 0 1px rgba(0,229,160,0.06),
        0 30px 80px rgba(0,0,0,0.6),
        inset 0 1px 0 rgba(255,255,255,0.06);
    animation: cardIn 0.6s cubic-bezier(.16,1,.3,1) both;
}

@keyframes cardIn {
    from { opacity: 0; transform: translateY(24px) scale(0.97); }
    to   { opacity: 1; transform: translateY(0) scale(1); }
}

/* ─── HEADER ─── */
.header {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: 24px;
}

.lock-icon {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    background: linear-gradient(135deg, rgba(0,229,160,0.15), rgba(0,184,255,0.10));
    border: 1px solid rgba(0,229,160,0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent);
    margin-bottom: 12px;
    box-shadow: 0 0 20px rgba(0,229,160,0.12);
}

.header h1 {
    font-family: var(--display);
    font-size: 1.75rem;
    font-weight: 800;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, var(--accent), var(--accent2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
    margin-bottom: 4px;
}

.subtitle {
    font-size: 0.72rem;
    color: var(--muted);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    font-weight: 600;
}

/* ─── PASSWORD OUTPUT ─── */
#password {
    display: grid;
    grid-template-columns: 1fr auto;
    border-radius: var(--radius-sm);
    overflow: hidden;
    border: 1px solid var(--border);
    margin-bottom: 10px;
    background: var(--surface2);
    box-shadow: inset 0 2px 8px rgba(0,0,0,0.3);
}

#result {
    padding: 14px 16px;
    background: transparent;
    color: var(--accent);
    font-family: var(--mono);
    font-size: 1.05rem;
    font-weight: 700;
    border: none;
    outline: none;
    letter-spacing: 0.05em;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    width: 100%;
    transition: color var(--transition);
}

#copy-button {
    display: flex;
    align-items: center;
    gap: 7px;
    background: linear-gradient(135deg, rgba(0,229,160,0.15), rgba(0,184,255,0.10));
    color: var(--accent);
    padding: 14px 18px;
    border: none;
    border-left: 1px solid var(--border);
    cursor: pointer;
    font-family: var(--mono);
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    transition: background var(--transition), color var(--transition);
    white-space: nowrap;
}

#copy-button:hover {
    background: rgba(0,229,160,0.25);
    color: #fff;
}

#copy-button:active {
    background: rgba(0,229,160,0.35);
}

/* ─── STRENGTH BAR ─── */
.strength-bar-wrap {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 22px;
}

.strength-bar {
    flex: 1;
    height: 4px;
    background: var(--surface2);
    border-radius: 100px;
    overflow: hidden;
    border: 1px solid var(--border);
}

.strength-fill {
    height: 100%;
    width: 0%;
    border-radius: 100px;
    background: var(--muted);
    transition: width 0.5s cubic-bezier(.4,0,.2,1), background 0.4s ease;
}

.strength-label {
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--muted);
    font-family: var(--mono);
    min-width: 52px;
    text-align: right;
}

/* ─── LENGTH SECTION ─── */
.length-section {
    margin-bottom: 20px;
}

.length-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 10px;
}

.length-header label {
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--muted);
}

.length-header o {
    font-family: var(--mono);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text);
    min-width: 28px;
    text-align: right;
}

/* ─── RANGE SLIDER ─── */
#password-length {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 4px;
    border-radius: 100px;
    background: linear-gradient(to right, var(--accent) 0%, var(--accent) var(--pct, 0%), var(--surface2) var(--pct, 0%));
    outline: none;
    cursor: pointer;
    border: 1px solid var(--border);
}

#password-length::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--bg);
    border: 2.5px solid var(--accent);
    cursor: pointer;
    box-shadow: 0 0 12px rgba(0,229,160,0.4);
    transition: box-shadow var(--transition), transform var(--transition);
}

#password-length::-webkit-slider-thumb:hover {
    box-shadow: 0 0 20px rgba(0,229,160,0.7);
    transform: scale(1.15);
}

#password-length::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--bg);
    border: 2.5px solid var(--accent);
    cursor: pointer;
    box-shadow: 0 0 12px rgba(0,229,160,0.4);
}

/* ─── OPTIONS GRID ─── */
#options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
    margin-bottom: 22px;
}

#options label {
    position: relative;
    display: block;
    cursor: pointer;
}

#options label input[type="checkbox"] {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.option-content {
    display: flex;
    align-items: center;
    gap: 10px;
    background: var(--surface2);
    border: 1px solid var(--border);
    padding: 12px 14px;
    border-radius: var(--radius-sm);
    transition: background var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.option-icon {
    font-family: var(--mono);
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--muted);
    min-width: 30px;
    transition: color var(--transition);
}

.option-text {
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--muted);
    transition: color var(--transition);
    letter-spacing: 0.02em;
}

/* checked state */
#options label input:checked ~ .option-content {
    background: rgba(0,229,160,0.08);
    border-color: rgba(0,229,160,0.35);
    box-shadow: 0 0 14px rgba(0,229,160,0.08);
}

#options label input:checked ~ .option-content .option-icon {
    color: var(--accent);
}

#options label input:checked ~ .option-content .option-text {
    color: var(--text);
}

#options label:hover .option-content {
    background: rgba(255,255,255,0.04);
    border-color: rgba(255,255,255,0.12);
}

/* ─── GENERATE BUTTON ─── */
#generate-button {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 16px;
    background: linear-gradient(135deg, var(--accent), #00c8ff);
    color: #000;
    border: none;
    border-radius: var(--radius-sm);
    font-family: var(--mono);
    font-size: 0.85rem;
    font-weight: 700;
    letter-spacing: 0.15em;
    cursor: pointer;
    transition: opacity var(--transition), transform var(--transition), box-shadow var(--transition);
    box-shadow: 0 0 28px rgba(0,229,160,0.25), 0 4px 16px rgba(0,0,0,0.3);
    position: relative;
    overflow: hidden;
}

#generate-button::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255,255,255,0.18), transparent);
    opacity: 0;
    transition: opacity var(--transition);
}

#generate-button:hover {
    opacity: 0.92;
    transform: translateY(-2px);
    box-shadow: 0 0 40px rgba(0,229,160,0.4), 0 8px 24px rgba(0,0,0,0.4);
}

#generate-button:hover::before { opacity: 1; }

#generate-button:active {
    transform: translateY(0);
    box-shadow: 0 0 20px rgba(0,229,160,0.2);
}

.btn-arrow {
    font-size: 1rem;
    transition: transform var(--transition);
}

#generate-button:hover .btn-arrow {
    transform: translateX(4px);
}

/* ─── SLIDER GRADIENT UPDATE (JS hook) ─── */
/* Update via JS: el.style.setProperty('--pct', pct+'%') */