:root {
    --primary: #00ff88;
    --secondary: #003b27;
    --dark: #0a0a0a;
    --light: #e0e0e0;
    --glow: 0 0 10px var(--primary), 0 0 20px var(--primary);
}

html {
    scroll-behavior: smooth;
}

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

body {
    background: #0000 url('image.png') no-repeat center center;
    background-size: cover;
    color: var(--light);
    font-family: 'Rajdhani', sans-serif;
    overflow-x: hidden;
}

h1,
h2,
h3,
h4 {
    font-family: 'Orbitron', sans-serif;
    text-transform: uppercase;
    letter-spacing: 2px;
    text-align: center;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
}



.hero {
    text-align: center;
    padding: 4rem 0;
    position: relative;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    color: var(--primary);
    text-shadow: var(--glow);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% {
        text-shadow: 0 0 10px var(--primary), 0 0 20px var(--primary);
    }

    50% {
        text-shadow: 0 0 15px var(--primary), 0 0 30px var(--primary);
    }

    100% {
        text-shadow: 0 0 10px var(--primary), 0 0 20px var(--primary);
    }
}

.hero p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 2rem;
    line-height: 1.6;
}

.core {
    font-size: xx-large;
    margin-top: 50px;
}
.ds-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr); /* 4 cards per row */
    gap: 2rem;
    margin: 3rem 0;
}


.ds-card {
    background: rgba(10, 10, 10, 0.7);
    border: 2px solid var(--primary); /* Green border */
    border-radius: 35px;
    padding: 1.5rem;
    text-align: center; /* Center contents */
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    transition: 0.1s ease;
}

.ds-card:hover {
    /* transform: translateY(-5px); */
    transform: scale(1.5);
    box-shadow: 0px 0px 30px var(--primary); /* Green glow */
}

.explore-btn {
    background: var(--primary);       /* Green background */
    color: white;                     /* White text */
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    margin-top: auto;
    cursor: pointer;
    font-family: 'Orbitron', sans-serif;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.explore-btn:hover {
    box-shadow: var(--glow);
    background-color: var(--primary);
    color: var(--dark);
}


.ds-card::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(to bottom right,
            transparent,
            transparent,
            transparent,
            var(--primary));
    transform: rotate(30deg);
    transition: all 0.6s ease;
    opacity: 0;
}

.ds-card:hover::before {
    animation: shine 1.5s;
}

@keyframes shine {
    0% {
        opacity: 0;
        left: -50%;
    }

    50% {
        opacity: 0.5;
    }

    100% {
        opacity: 0;
        left: 150%;
    }
}

.ds-card h3 {
    color: var(--primary);
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.ds-card p {
    margin-bottom: 1.5rem;
    line-height: 1.5;
}

.ds-card .complexity {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.ds-card .complexity span {
    background: var(--secondary);
    padding: 0.3rem 0.6rem;
    border-radius: 4px;
}
@media (max-width: 1024px) {
    .ds-grid {
        grid-template-columns: repeat(2, 1fr); /* 2 columns for tablets */
    }

    .hero h1 {
        font-size: 2.8rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .left-side, .right-side {
        font-size: 1.4rem;
    }

    .answer {
        width: 100%;
        font-size: 1rem;
    }
}

@media (max-width: 768px) {
    .ds-grid {
        grid-template-columns: 1fr; /* Stack for mobile */
    }

    .hero h1 {
        font-size: 2.2rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .deepdive {
        width: 80%;
        font-size: 1.2rem;
    }

    .why-dsa {
        flex-direction: column;
        height: auto;
        padding: 2rem;
    }

    .left-side, .right-side {
        width: 100%;
        font-size: 1.2rem;
        text-align: center;
        margin: 0;
    }

    .answer {
        width: 90%;
        padding: 1rem;
    }

    .tips h3 {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.8rem;
    }

    .hero p {
        font-size: 0.9rem;
    }

    .deepdive {
        font-size: 1rem;
        padding: 0.75rem;
    }

    .ds-card h3 {
        font-size: 1.2rem;
    }

    .ds-card p {
        font-size: 0.9rem;
    }

    .cheat-sheet-links a {
        padding: 0.7rem 1.2rem;
        font-size: 0.9rem;
    }

    .left-side, .right-side {
        font-size: 1rem;
        line-height: 1.4;
    }

    .tips {
        padding: 1rem;
    }

    .answer ul li {
        line-height: 1.8rem;
    }

    footer {
        font-size: 0.9rem;
        padding: 1rem;
    }
}

.deepdive{
    display: block;
    margin: 2rem auto;
    background-color: #00cc6e;
    color: white;
    width: 300px;
    border: none;
    height: 50px;
    font-size: x-large;
    letter-spacing: 3px;
    font-weight: 900;
    border-radius: 15px;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.deepdive:hover{
    transform: scale(1.05);
    background-color: #003b27;
    box-shadow: 0 0 10px var(--primary);
}

/* Click Glow Animation */
.ds-card:active {
    box-shadow: 0 0 20px var(--primary), 0 0 40px var(--primary);
    transform: scale(0.98);
    transition: all 0.1s ease-in-out;
}

/* Cheat Sheet Styles */
.cheat-sheets {
    margin-top: 12rem;
    margin-bottom: 8rem;
    text-align: center;
}
.cheat-sheet-links {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    justify-content: center;
    margin-top: 2rem;
}
.cheat-sheet-links a {
    background-color: var(--primary);
    color: black;
    font-weight: bold;
    padding: 1rem 2rem;
    border-radius: 10px;
    text-decoration: none;
    box-shadow: 0 0 10px var(--primary);
    transition: background-color 0.3s, transform 0.3s;
}
.cheat-sheet-links a:hover {
    background-color: #00ff884c;
    transform: scale(1.05);
}

/* Extra Cards */
.hidden {
    display: none;
}
.fade-in {
    animation: fadeInUp 0.5s ease-in-out;
}
@keyframes fadeInUp {
    0% {
        transform: translateY(40px);
        opacity: 0;
    }
    100% {
        transform: translateY(0px);
        opacity: 1;
    }
}

.why-dsa {
    text-align: center;
    display: flex;
    justify-content: space-around;
    align-items: center;
    padding: 4rem;
    height: 100vh;
    flex-direction: row;
    box-sizing: border-box;
    width: auto;
}
.left-side {
    flex: 1;
    font-size: 2rem;
    line-height: 1.5;
    font-weight: bold;
    text-transform: uppercase;
    width: 400px;
    text-align: left;
    margin-right: 40px;
}
.right-side {
    flex: 1;
    background-color: rgba(0, 255, 136, 0.15); /* green transparent */
    padding: 2rem;
    border-radius: 20px;
    font-size: 1.1rem;
    line-height: 1.6;
    color: white;
    font-weight: 500;
    width: min-content;
    line-height: 40px;
}
@media (max-width: 768px) {
    .why-dsa {
        flex-direction: column;
        gap: 1rem;
    }

    .left-side,
    .right-side {
        width: 100%;
    }
}
.tips {
    margin: 40px auto;
    margin-top: 150px;
    padding: 2rem;
    text-align: center;
}

.tips h3{
    font-size: xx-large;
    margin-bottom: 20px;
    font-weight: 900;
}
.answer {
    background-color: rgba(0, 255, 136, 0.15); /* Green with 40% opacity */
    color: white;
    padding: 1.5rem;
    border-radius: 10px;
    font-size: 1.1rem;
    line-height: 1.6;
    max-width: 800px;
    margin: 0 auto;
    width: 700px;
}
.answer ul li{
    line-height: 40px;
    letter-spacing: 1.2px;
}

footer {
    text-align: center;
    padding: 2rem;
    background-color: rgba(0, 0, 0, 0.7);;
    color: var(--primary);
    font-size: 1rem;
    margin-top: 3rem;
    border: none;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    nav ul {
        gap: 1rem;
    }

    .ds-grid {
        grid-template-columns: 1fr;
    }
}