:root {
    --color-primary: #b64fff;
    --color-primary-gradient: linear-gradient(135deg, #b64fff, #8003fd);
    --color-bg: #0A0A0B;
    --color-bg-alt: #18181B;
    --color-text: #F8F9FA;
    --color-text-dim: #94A3B8;
    --color-glass-fill: rgba(18, 18, 20, 0.7);
    --color-glass-stroke: #27272A;
    --radius-xl: 24px;
    --font-main: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

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

body {
    background-color: var(--color-bg);
    background-image:
        linear-gradient(to right, rgba(39, 39, 42, 0.2) 1px, transparent 1px),
        linear-gradient(to bottom, rgba(39, 39, 42, 0.2) 1px, transparent 1px);
    background-size: 40px 40px;
    color: var(--color-text);
    font-family: var(--font-main);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
}

.showcase-wrapper {
    position: relative;
    padding: 20px;
    border-radius: var(--radius-xl);
    background: radial-gradient(circle at 50% -20%, rgba(182, 79, 255, 0.15) 0%, transparent 70%);
}

.glass-panel {
    background: var(--color-glass-fill);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--color-glass-stroke);
    border-radius: var(--radius-xl);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

.calculator-bento {
    padding: 24px;
    width: 340px;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.calc-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 12px;
    border-bottom: 1px solid rgba(255,255,255,0.05);
}

.brand-tag .mono-tag {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--color-primary);
    background: rgba(182, 79, 255, 0.1);
    padding: 4px 8px;
    border-radius: 6px;
    letter-spacing: 0.05em;
}

.window-controls {
    display: flex;
    gap: 6px;
}

.control-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--color-glass-stroke);
}

.display {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 12px;
    padding: 20px;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    justify-content: center;
    min-height: 90px;
    word-wrap: break-word;
    word-break: break-all;
    border: 1px solid rgba(255,255,255,0.02);
}

.previous-operand {
    color: var(--color-text-dim);
    font-size: 0.9rem;
    min-height: 1.2rem;
    font-family: var(--font-mono);
}

.current-operand {
    color: var(--color-text);
    font-size: 2.5rem;
    font-weight: 600;
    letter-spacing: -1px;
}

.keypad {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

.btn {
    cursor: pointer;
    background: var(--color-bg-alt);
    border: 1px solid var(--color-glass-stroke);
    color: var(--color-text);
    font-size: 1.25rem;
    font-weight: 600;
    padding: 16px 0;
    border-radius: 12px;
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
    display: flex;
    justify-content: center;
    align-items: center;
    user-select: none;
}

.btn:hover {
    background: #27272A;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.btn:active {
    transform: translateY(1px);
}

.span-two {
    grid-column: span 2;
}

.btn-action {
    color: #ef4444; /* Subtle red for actions like AC/DEL */
    background: rgba(239, 68, 68, 0.05);
}
.btn-action:hover {
    background: rgba(239, 68, 68, 0.1);
}

.btn-operator {
    color: var(--color-primary);
    background: rgba(182, 79, 255, 0.05);
}

.btn-operator:hover {
    background: rgba(182, 79, 255, 0.1);
}

.btn-equals {
    background: var(--color-primary-gradient);
    border: none;
    color: white;
    box-shadow: 0 4px 15px rgba(182, 79, 255, 0.3);
}

.btn-equals:hover {
    box-shadow: 0 6px 20px rgba(182, 79, 255, 0.4);
    background: linear-gradient(135deg, #c77bff, #9527ff);
}