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

.cute-heading {
    font-family: 'Press Start 2P', cursive;
    color: #ff66a3;
    text-align: center;
    font-size: 18px;
    margin-bottom: 20px;
    text-shadow: 2px 2px 0 #ffb3d9, 4px 4px 0 #ffd6e7;
    letter-spacing: 2px;
    background-color: #fff0f7;
    display: inline;
    padding: 10px 15px;
    border: 4px solid #ff9ec6;
    border-radius: 12px;
    box-shadow: 4px 4px 0 #ffb3d9;
    animation: gentlePop 1s ease-out;
}

/* Soft pop-in animation */
@keyframes gentlePop {
    0% { transform: scale(0.8); opacity: 0; }
    100% { transform: scale(1); opacity: 1; }
}
body {
    background-color: #ffebf3;
    display: flex;
    flex-direction: column; /* stack vertically */
    justify-content: center;
    align-items: center;
    height: 100vh;
    font-family: 'Press Start 2P', cursive;
}

/* Calculator Container */
.calculator {
    width: 300px;
    border: 4px solid #ff9ec6;
    background-color: #ffd6e7;
    padding: 20px;
    border-radius: 15px; /* soft and cute */
    box-shadow: 6px 6px 0 #ffb3d9; /* blocky pastel shadow */
}

/* Display */
.display {
    position: relative;
    background-color: #fff0f7;
    border: 4px solid #ff9ec6;
    padding: 15px 10px;
    margin-bottom: 20px;
    color: #ff66a3;
    text-align: right;
    font-size: 20px;
    height: 80px;
    overflow: hidden;
    border-radius: 10px;
    box-shadow: inset -3px -3px 0 #ffd6e7, inset 3px 3px 0 #ffb3d9;
}

.current-operation {
    font-size: 14px;
    color: #ff85b8;
    height: 20px;
    overflow: hidden;
}

.current-input {
    font-size: 24px;
    margin-top: 10px;
}

/* Buttons Grid */
.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 10px;
}

/* Generic Button */
.btn {
    background-color: #ffb6d9;
    border: 3px solid #ff85b8;
    color: white;
    font-family: 'Press Start 2P', cursive;
    font-size: 14px;
    padding: 15px 0;
    cursor: pointer;
    transition: transform 0.05s steps(1);
    outline: none;
    border-radius: 10px;
    box-shadow: 3px 3px 0 #ff85b8;
    background-image: linear-gradient(145deg, rgba(255,255,255,0.4) 0%, transparent 40%);
}

.btn:active {
    transform: translate(2px, 2px) scale(0.95);
    box-shadow: 1px 1px 0 #ff85b8;
    background-color: #ff9ec6;
}

/* Special Buttons */
.btn-number {
    background-color: white;
    color: #ff66a3;
    border: 3px solid #ffb6d9;
    box-shadow: 3px 3px 0 #ffb6d9;
}

.btn-operator {
    background-color: #ff66a3;
}

.btn-equals {
    background-color: #ff85b8;
}

.btn-clear, .btn-backspace {
    background-color: #ffb3d9;
    color: white;
}

.btn-history {
    background-color: #d4a5ff;
}

.btn-history.new {
    animation: blink 0.5s 3;
}

@keyframes blink {
    0% { background-color: #d4a5ff; }
    50% { background-color: #c18cff; }
    100% { background-color: #d4a5ff; }
}

/* History Panel */
.history-panel {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 280px;
    background-color: #ffebf3;
    border: 4px solid #ff9ec6;
    padding: 20px;
    z-index: 10;
    display: none;
    color: #ff66a3;
    max-height: 400px;
    overflow-y: auto;
    border-radius: 15px;
    box-shadow: 6px 6px 0 #ffb3d9;
}

.history-panel h3 {
    text-align: center;
    margin-bottom: 15px;
    font-size: 16px;
    color: #ff85b8;
}

.history-item {
    margin-bottom: 10px;
    padding-bottom: 10px;
    border-bottom: 2px solid #ffd6e7;
    font-size: 12px;
}

/* Close Button */
.close-history {
    position: absolute;
    top: 10px;
    right: 10px;
    background: #ff9ec6;
    border: none;
    color: white;
    font-size: 14px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    cursor: pointer;
}

/* Clear History */
.clear-history {
    background-color: #ff9ec6;
    border: 3px solid #ff85b8;
    color: white;
    font-family: 'Press Start 2P', cursive;
    font-size: 12px;
    padding: 10px;
    margin-top: 10px;
    width: 100%;
    cursor: pointer;
    border-radius: 8px;
    box-shadow: 3px 3px 0 #ff85b8;
}

.clear-history:active {
    transform: translate(2px, 2px);
    background-color: #ff85b8;
}

/* Error Message */
.error-message {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: #ffebf3;
    border: 4px solid #ff9ec6;
    padding: 20px;
    z-index: 10;
    display: none;
    color: #ff66a3;
    text-align: center;
    animation: errorShake 0.5s;
    border-radius: 15px;
    box-shadow: 6px 6px 0 #ffb3d9;
}

@keyframes errorShake {
    0%, 100% { transform: translate(-50%, -50%); }
    20% { transform: translate(-52%, -50%); }
    40% { transform: translate(-48%, -50%); }
    60% { transform: translate(-52%, -50%); }
    80% { transform: translate(-48%, -50%); }
}

/* Close Error */
.close-error {
    margin-top: 15px;
    background-color: #ff9ec6;
    border: 3px solid #ff85b8;
    color: white;
    font-family: 'Press Start 2P', cursive;
    font-size: 12px;
    padding: 10px;
    cursor: pointer;
    border-radius: 8px;
    box-shadow: 3px 3px 0 #ff85b8;
}

.overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255, 214, 231, 0.7);
    z-index: 5;
    display: none;
}