@import url('https://fonts.googleapis.com/css2?family=Orbitron:wght@400;500;600;700&family=Roboto+Mono:wght@300;400;500&display=swap');

:root {
    --primary-blue: #0626f8;
    --dark-blue: #1500ff;
    --light-blue: #5dade2;
    --black: #1a1a1a;
    --dark-gray: #2c3e50;
    --medium-gray: #7f8c8d;
    --light-gray: #ecf0f1;
    --white: #ffffff;
    --gradient: linear-gradient(135deg, var(--primary-blue), var(--dark-blue));
}

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

body {
    font-family: 'Roboto Mono', monospace;
    background-color: var(--black);
    color: var(--light-gray);
    line-height: 1.6;
}

header {
    background: var(--gradient);
    color: var(--white);
    padding: 1.5rem 0;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    position: relative;
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    margin: 0;
    font-size: 2rem;
    font-weight: 600;
    text-shadow: 1px 1px 3px rgba(0, 0, 0, 0.5);
    font-family: 'Orbitron', sans-serif;
}

.back-btn {
    color: var(--white);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    transition: background-color 0.3s;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background-color: rgba(0, 0, 0, 0.3);
}

.back-btn:hover {
    background-color: rgba(0, 0, 0, 0.5);
}

.math-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    max-width: 1400px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.formulas-panel {
    background: var(--dark-gray);
    border-radius: 12px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
    padding: 1.5rem;
    height: fit-content;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.formulas-panel h2 {
    color: var(--white);
    margin-bottom: 1.5rem;
    text-align: center;
    font-family: 'Orbitron', sans-serif;
    position: relative;
    padding-bottom: 0.5rem;
}

.formulas-panel h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: var(--gradient);
    border-radius: 3px;
}

.formula-categories {
    margin-bottom: 1.5rem;
}

.category {
    margin-bottom: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    overflow: hidden;
    background: rgba(0, 0, 0, 0.2);
}

.category h3 {
    background: rgba(52, 152, 219, 0.2);
    margin: 0;
    padding: 0.8rem 1rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--light-blue);
    font-weight: 600;
    transition: background 0.3s;
}

.category h3:hover {
    background: rgba(52, 152, 219, 0.3);
}

.category h3::after {
    content: '+';
    font-size: 1.2rem;
}

.category.active h3::after {
    content: '-';
}

.formula-list {
    display: none;
    padding: 0.5rem;
}

.category.active .formula-list {
    display: block;
}

.formula {
    padding: 0.8rem 1rem;
    margin: 0.3rem 0;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.2s;
    border-left: 3px solid transparent;
}

.formula:hover {
    background: rgba(52, 152, 219, 0.2);
    border-left-color: var(--primary-blue);
    transform: translateX(5px);
}

.formula-details {
    margin-top: 2rem;
}

#selected-formula-title {
    color: var(--primary-blue);
    margin-bottom: 1rem;
    text-align: center;
    font-family: 'Orbitron', sans-serif;
}

.formula-description {
    background: rgba(0, 0, 0, 0.3);
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
    font-size: 0.95rem;
    border-left: 3px solid var(--primary-blue);
}

.formula-inputs {
    margin-bottom: 1rem;
}

.input-group {
    margin-bottom: 1rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--light-gray);
}

.input-group input {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 5px;
    font-size: 1rem;
    background: rgba(0, 0, 0, 0.3);
    color: var(--white);
    transition: border-color 0.3s;
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary-blue);
}

#calculate-formula-btn {
    background: var(--gradient);
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 5px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    width: 100%;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
}

#calculate-formula-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.4);
    background: linear-gradient(135deg, var(--dark-blue), var(--primary-blue));
}

.formula-result {
    margin-top: 1rem;
    padding: 1rem;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 8px;
    font-weight: bold;
    text-align: center;
    min-height: 50px;
    border-left: 3px solid var(--primary-blue);
    color: var(--light-gray);
}

.calculator-panel {
    background: var(--dark-gray);
    border-radius: 12px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
    padding: 1.5rem;
    height: fit-content;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.calculator {
    background: var(--black);
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
    width: 100%;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.display {
    padding: 1.5rem;
    text-align: right;
    background: rgba(0, 0, 0, 0.5);
    color: white;
    border-bottom: 2px solid var(--primary-blue);
    min-height: 120px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
}

.previous-operand {
    font-size: 1.2rem;
    color: var(--medium-gray);
    min-height: 1.5rem;
    font-family: 'Roboto Mono', monospace;
}

.current-operand {
    font-size: 2.5rem;
    word-wrap: break-word;
    font-family: 'Orbitron', sans-serif;
    color: var(--white);
    text-shadow: 0 0 5px rgba(255, 255, 255, 0.3);
}

.buttons {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 1px;
    background: rgba(0, 0, 0, 0.2);
}

.buttons > button {
    border: none;
    padding: 1rem;
    font-size: 1rem;
    cursor: pointer;
    background: rgba(0, 0, 0, 0.5);
    color: var(--light-gray);
    transition: all 0.2s;
    font-family: 'Orbitron', sans-serif;
    font-weight: 500;
}

.buttons > button:hover {
    background: rgba(0, 0, 0, 0.7);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
}

.buttons > button:active {
    transform: translateY(0);
    box-shadow: none;
}

.buttons > button[data-action] {
    background: rgba(0, 0, 0, 0.6);
}

.buttons > button[data-action="add"],
.buttons > button[data-action="subtract"],
.buttons > button[data-action="multiply"],
.buttons > button[data-action="divide"],
.buttons > button[data-action="equals"] {
    background: var(--primary-blue);
    color: var(--white);
}

.buttons > button[data-action="add"]:hover,
.buttons > button[data-action="subtract"]:hover,
.buttons > button[data-action="multiply"]:hover,
.buttons > button[data-action="divide"]:hover,
.buttons > button[data-action="equals"]:hover {
    background: var(--dark-blue);
}

.buttons > button[data-action="clear"],
.buttons > button[data-action="delete"] {
    background: rgba(41, 128, 185, 0.3);
    color: var(--light-blue);
}

.buttons > button[data-action="clear"]:hover,
.buttons > button[data-action="delete"]:hover {
    background: rgba(41, 128, 185, 0.5);
}

.buttons > button[data-action="sin"],
.buttons > button[data-action="cos"],
.buttons > button[data-action="tan"],
.buttons > button[data-action="log"],
.buttons > button[data-action="ln"] {
    background: rgba(41, 128, 185, 0.4);
}

.buttons > button[data-action="square-root"],
.buttons > button[data-action="power"],
.buttons > button[data-action="factorial"],
.buttons > button[data-action="reciprocal"] {
    background: rgba(41, 128, 185, 0.5);
}

.buttons > button[data-action="pi"],
.buttons > button[data-action="e"] {
    background: rgba(41, 128, 185, 0.6);
}

.buttons > button[data-number] {
    background: rgba(255, 255, 255, 0.05);
}

.buttons > button[data-number]:hover {
    background: rgba(255, 255, 255, 0.1);
}

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

/* How to Use Section */
.how-to-use {
    background: var(--dark-gray);
    max-width: 1400px;
    margin: 2rem auto 0;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
    grid-column: 1 / -1;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.how-to-use h2 {
    text-align: center;
    color: var(--white);
    margin-bottom: 1.5rem;
    font-family: 'Orbitron', sans-serif;
}

.steps-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.step {
    background: rgba(0, 0, 0, 0.3);
    padding: 1.5rem;
    border-radius: 8px;
    position: relative;
    transition: transform 0.3s;
    border-left: 3px solid var(--primary-blue);
}

.step:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
}

.step-number {
    display: inline-block;
    width: 30px;
    height: 30px;
    background: var(--gradient);
    color: white;
    border-radius: 50%;
    text-align: center;
    line-height: 30px;
    font-weight: bold;
    margin-right: 10px;
}

.toggle-details {
    background: transparent;
    color: var(--primary-blue);
    border: 2px solid var(--primary-blue);
    margin: 0 auto;
    display: block;
    width: auto;
    padding: 0.8rem 1.5rem;
    transition: all 0.3s;
    cursor: pointer;
    border-radius: 5px;
}

.toggle-details:hover {
    background: rgba(52, 152, 219, 0.1);
    transform: none;
    box-shadow: none;
}

.detailed-instructions {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s ease;
    margin-top: 1rem;
}

.detailed-instructions.show {
    max-height: 500px;
}

.detailed-instructions h3 {
    color: var(--white);
    margin-bottom: 0.8rem;
}

.detailed-instructions ul {
    padding-left: 1.2rem;
}

.detailed-instructions li {
    margin-bottom: 0.5rem;
    color: var(--light-gray);
}

/* Animation for button presses */
@keyframes buttonPress {
    0% { transform: scale(1); }
    50% { transform: scale(0.95); }
    100% { transform: scale(1); }
}

.buttons > button:active {
    animation: buttonPress 0.1s ease;
}

@media (max-width: 1024px) {
    .math-container {
        grid-template-columns: 1fr;
    }
    
    .calculator-panel {
        order: -1;
    }
}

@media (max-width: 768px) {
    .buttons {
        grid-template-columns: repeat(4, 1fr);
    }
    
    .buttons > button {
        padding: 0.8rem;
        font-size: 0.9rem;
    }
    
    .current-operand {
        font-size: 2rem;
    }
    
    header h1 {
        font-size: 1.5rem;
    }
    
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }
    
    .back-btn {
        position: static;
        transform: none;
    }
}

@media (max-width: 480px) {
    .buttons {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .buttons > button {
        padding: 0.6rem;
        font-size: 0.8rem;
    }
    
    .current-operand {
        font-size: 1.5rem;
    }
    
    .steps-container {
        grid-template-columns: 1fr;
    }
}