:root {
    --bg-color: #080808;
    --second-bg-color: #131313;
    --text-color: #fff;
    --main-color: #00ffee;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    text-decoration: none;
    border: none;
    outline: none;
    scroll-behavior: smooth;
    font-family: 'Poppins', sans-serif;
}

html {
    font-size: 62.5%;
    overflow-x: hidden;
}

body {
    background: var(--bg-color);
    color: var(--text-color);
    overflow-x: hidden;
}

span {
    color: var(--main-color);
    text-shadow: 0 0 25px var(--main-color);
}

/* Header */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    padding: 1rem 9%;
    background: var(--bg-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 100;
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.logo {
    font-size: 2.5rem;
    color: var(--text-color);
    font-weight: 700;
    cursor: pointer;
}

.logo span {
    color: var(--main-color);
}

#menu-icon {
    font-size: 3.6rem;
    color: var(--main-color);
    cursor: pointer;
    display: none;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 300px;
    height: 100vh;
    background: var(--bg-color);
    padding: 8rem 2rem 2rem;
    overflow-y: auto;
    transition: 0.3s ease;
    z-index: 99;
    border-right: 2px solid var(--main-color);
}

.navbar::-webkit-scrollbar {
    width: 5px;
}

.navbar::-webkit-scrollbar-track {
    background: var(--bg-color);
}

.navbar::-webkit-scrollbar-thumb {
    background: var(--main-color);
    border-radius: 5px;
}

/* Content Area */
.content-area {
    padding: 8rem 9% 2rem;
    max-width: 1200px;
    margin: 0 auto;
    transition: 0.3s ease;
}

/* Menu Items */
.menu-group {
    margin-bottom: 2.5rem;
}

.menu-title {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--main-color);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid rgba(0, 255, 238, 0.2);
}

.menu-items {
    padding-left: 1rem;
}

.menu-item {
    font-size: 1.4rem;
    color: var(--text-color);
    padding: 1rem 1.5rem;
    cursor: pointer;
    transition: 0.3s ease;
    border-radius: 5px;
}

.menu-item:hover {
    background: rgba(0, 255, 238, 0.1);
    color: var(--main-color);
    padding-left: 1.5rem;
}

.page-title {
    background: rgba(255, 255, 255, 0.1);
    padding: 0.5rem 1.5rem;
    border-radius: 5px;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

#current-menu-title {
    color: #fff;
    font-size: 1.2rem;
    font-weight: 600;
}

#current-submenu-title {
    color: #0ef;
    font-size: 1.2rem;
    font-weight: 500;
}

.title-separator {
    color: rgba(255, 255, 255, 0.5);
    font-size: 1.2rem;
    font-weight: 300;
}

/* Formula Section */
.formula-section {
    margin-bottom: 2.5rem;
    padding: 2rem;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
    border: 1px solid rgba(0, 255, 238, 0.1);
}

.formula-title {
    color: var(--main-color);
    font-size: 2.2rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--main-color);
}

.formula-desc {
    color: var(--text-color);
    font-size: 1.6rem;
    line-height: 1.6;
    margin-bottom: 1.5rem;
    opacity: 0.9;
}

.formula-example {
    background: rgba(0, 0, 0, 0.2);
    padding: 2rem;
    border-radius: 8px;
    margin-top: 1.5rem;
    border: 1px solid rgba(0, 255, 238, 0.05);
}

.calculation-title, .importance-title, .example-title, .note-title {
    color: var(--main-color);
    font-weight: 600;
    font-size: 1.4rem;
    margin: 1.5rem 0 1rem 0;
}

.formula-example p {
    color: var(--text-color);
    margin-bottom: 1rem;
    line-height: 1.6;
    font-size: 1.2rem;
    opacity: 0.9;
}

.formula-example ul {
    margin: 1rem 0;
    padding-left: 2rem;
    color: var(--text-color);
    opacity: 0.9;
    font-size: 1.2rem;
}

.formula-example li {
    margin-bottom: 1rem;
    line-height: 1.5;
}

.example-calculation {
    font-size: 1.3rem !important;
    margin: 1rem 0;
    color: var(--text-color);
    line-height: 1.6;
    opacity: 0.9;
}

/* Responsive Design */
@media (min-width: 1921px) {
    html {
        font-size: 14px;
    }
    .navbar {
        width: 350px;
    }
    .content-area {
        margin-left: 350px;
        padding: 10rem 5rem 5rem;
    }
}

@media (max-width: 1920px) {
    html {
        font-size: 12px;
    }
    .navbar {
        width: 320px;
    }
    .content-area {
        margin-left: 320px;
    }
}

@media (max-width: 1366px) {
    html {
        font-size: 10px;
    }
    .navbar {
        width: 280px;
    }
    .content-area {
        margin-left: 280px;
    }
}

@media (max-width: 991px) {
    html {
        font-size: 9px;
    }
    .header {
        padding: 2rem 5%;
    }
    #menu-icon {
        display: block;
    }
    .navbar {
        left: -100%;
    }
    .navbar.active {
        left: 0;
        box-shadow: 0 0 15px rgba(0, 255, 238, 0.3);
    }
    .content-area {
        margin-left: 0;
        padding: 8rem 5% 3rem;
    }
}

@media (max-width: 768px) {
    .header {
        padding: 1rem 5%;
    }
    
    .page-title {
        padding: 0.3rem 0.8rem;
    }
    
    #current-menu-title,
    #current-submenu-title,
    .title-separator {
        font-size: 0.9rem;
    }
    
    .content-area {
        padding: 8rem 5% 2rem;
    }
    .header {
        padding: 1rem 5%;
    }
    .navbar {
        width: 100%;
        padding: 8rem 3rem 3rem;
    }
    .content-area {
        padding: 8rem 3% 3rem;
    }
    #current-menu-title {
        font-size: 1rem;
        margin-left: 1rem;
    }
}

@media (max-width: 576px) {
    html {
        font-size: 8px;
    }
    .header {
        padding: 1.5rem 2%;
    }
    .navbar {
        padding: 8rem 2rem 2rem;
    }
    .content-area {
        padding: 7rem 2% 2rem;
    }
    .formula-section {
        padding: 1.5rem;
    }
}

@media (max-width: 350px) {
    .logo {
        font-size: 2rem;
    }
    #menu-icon {
        font-size: 3rem;
    }
    .navbar {
        padding: 8rem 1.5rem 1.5rem;
    }
    .menu-title {
        font-size: 1.6rem;
    }
    .menu-item {
        font-size: 1.4rem;
    }
    .formula-section h3 {
        font-size: 1.8rem;
    }
}

.text {
    background-color: var(--second-bg-color);
    padding: 3rem;
    margin-bottom: 3rem;
    border-radius: 1rem;
    font-size: 1.6rem;
    border: 1px solid var(--main-color);
    box-shadow: 0 0 10px rgba(0, 255, 238, 0.1);
}

.text h2 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    color: var(--main-color);
}

.text h3 {
    font-size: 2rem;
    margin: 2rem 0;
    color: var(--main-color);
}

.text p {
    font-size: 1.6rem;
    margin: 1rem 0;
}

.text ul {
    margin: 1rem 0;
    padding-left: 2rem;
}

.text li {
    font-size: 1.6rem;
    margin: 0.5rem 0;
}

.text code {
    background: var(--bg-color);
    padding: 0.5rem;
    border-radius: 0.5rem;
    font-family: monospace;
    font-size: 1.4rem;
    color: var(--main-color);
    font-weight: 600;
}

.footer {
    background: var(--second-bg-color);
    padding: 4rem 0 2rem;
    margin-top: 4rem;
    margin-left: 0;
    border-top: 2px solid var(--main-color);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 4rem;
}

.footer-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.footer-section h3 {
    color: var(--main-color);
    font-size: 2rem;
    margin-bottom: 1rem;
    text-shadow: 0 0 10px rgba(0, 255, 238, 0.3);
}

.footer-section p,
.footer-section a {
    color: var(--text-color);
    font-size: 1.4rem;
    transition: 0.3s ease;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.footer-section a:hover {
    color: var(--main-color);
    transform: translateX(5px);
}

.social-links {
    display: flex;
    gap: 2rem;
}

.social-links a {
    font-size: 2.4rem;
    color: var(--text-color);
    transition: 0.3s ease;
}

.social-links a:hover {
    color: var(--main-color);
    transform: translateY(-5px);
}

.footer-bottom {
    text-align: center;
    padding-top: 3rem;
    margin-top: 3rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
    font-size: 1.4rem;
    color: var(--text-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 3rem;
    margin-top: 3rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
    font-size: 1.4rem;
    color: var(--text-color);
}