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

:root {
    --primary-color: #00897B;
    --primary-dark: #00695C;
    --primary-light: #4DB6AC;
    --secondary-color: #0288D1;
    --secondary-dark: #01579B;
    --background: #F5F5F5;
    --card-background: #FFFFFF;
    --text-primary: #212121;
    --text-secondary: #757575;
    --border-color: #E0E0E0;
    --shadow: 0 2px 8px rgba(0,0,0,0.1);
    --shadow-hover: 0 4px 16px rgba(0,0,0,0.15);
    --transition: all 0.3s ease;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 1.5rem;
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 1rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

.hamburger {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    display: flex;
    flex-direction: column;
    gap: 4px;
    transition: var(--transition);
}

.hamburger span {
    width: 24px;
    height: 3px;
    background-color: white;
    border-radius: 2px;
    transition: var(--transition);
}

.hamburger:hover span {
    background-color: #E0F2F1;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.side-menu {
    position: fixed;
    left: -300px;
    top: 0;
    width: 280px;
    height: 100vh;
    background-color: white;
    box-shadow: 2px 0 10px rgba(0,0,0,0.1);
    transition: left 0.3s ease;
    z-index: 1000;
    overflow-y: auto;
}

.side-menu.active {
    left: 0;
}

.close-btn {
    position: absolute;
    right: 1rem;
    top: 1rem;
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-secondary);
    transition: var(--transition);
}

.close-btn:hover {
    color: var(--text-primary);
}

.side-menu nav {
    margin-top: 4rem;
    display: flex;
    flex-direction: column;
}

.side-menu nav a {
    padding: 1rem 1.5rem;
    color: var(--text-primary);
    text-decoration: none;
    border-left: 3px solid transparent;
    transition: var(--transition);
}

.side-menu nav a:hover {
    background-color: #F5F5F5;
    border-left-color: var(--primary-color);
}

.side-menu nav a.active {
    background-color: #E0F2F1;
    border-left-color: var(--primary-color);
    color: var(--primary-color);
    font-weight: 600;
}

.side-menu nav a.temp-link {
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-style: italic;
    margin-top: 1rem;
    border-top: 1px solid var(--border-color);
    padding-top: 1.5rem;
}

.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    z-index: 999;
}

.overlay.active {
    opacity: 1;
    visibility: visible;
}

main {
    flex: 1;
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.hero {
    text-align: center;
    padding: 3rem 1rem;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    border-radius: 16px;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.tagline {
    font-size: 1.2rem;
    opacity: 0.95;
    margin-bottom: 1rem;
}

.hero-description {
    font-size: 1rem;
    opacity: 0.9;
    max-width: 700px;
    margin: 0 auto;
    line-height: 1.7;
}

.ad-container {
    margin: 2rem 0;
}

.ad-placeholder {
    background-color: var(--card-background);
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    padding: 4rem 2rem;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.calculators-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.calculator-card {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.calculator-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
}

.card-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.calculator-card h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.4rem;
}

.calculator-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: var(--transition);
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: var(--transition);
    margin: 0.5rem;
}

.btn-secondary:hover {
    background-color: var(--secondary-dark);
}

.btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    padding: 0.75rem 2rem;
    border: 2px solid var(--primary-color);
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: var(--transition);
}

.btn-outline:hover {
    background-color: var(--primary-color);
    color: white;
}

.about-section, .disclaimer-section {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin: 2rem 0;
}

.about-section h2, .disclaimer-section h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
    font-size: 1.8rem;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.feature-item h3 {
    color: var(--secondary-color);
    margin-bottom: 0.5rem;
}

.feature-item p {
    color: var(--text-secondary);
}

.calculator-page {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.calculator-page h1 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 2rem;
}

.calculator-section {
    background-color: #FAFAFA;
    padding: 2rem;
    border-radius: 8px;
    margin: 1.5rem 0;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-weight: 600;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: var(--transition);
    font-family: inherit;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

.result-box {
    background-color: var(--primary-light);
    color: white;
    padding: 2rem;
    border-radius: 8px;
    margin: 1.5rem 0;
    text-align: center;
}

.result-box h3 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.result-box .result-value {
    font-size: 2.5rem;
    font-weight: 700;
    margin: 1rem 0;
}

.explanation-section {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin: 2rem 0;
}

.explanation-section h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.explanation-section h3 {
    color: var(--secondary-color);
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
}

.explanation-section p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.7;
}

.navigation-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
    margin: 2rem 0;
}

.resistor-inputs {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.resistor-input-row {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.resistor-input-row input {
    flex: 1;
}

.btn-remove {
    background-color: #F44336;
    color: white;
    padding: 0.75rem 1rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
}

.btn-remove:hover {
    background-color: #D32F2F;
}

.btn-add {
    background-color: var(--secondary-color);
    color: white;
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    margin-top: 1rem;
    transition: var(--transition);
}

.btn-add:hover {
    background-color: var(--secondary-dark);
}

.color-band-preview {
    display: flex;
    gap: 0.5rem;
    margin: 2rem 0;
    justify-content: center;
    align-items: center;
}

.band {
    width: 40px;
    height: 100px;
    border-radius: 4px;
    border: 2px solid #333;
}

.resistor-body {
    width: 200px;
    height: 60px;
    background-color: #D2B48C;
    border-radius: 30px;
    position: relative;
}

footer {
    background-color: var(--text-primary);
    color: white;
    padding: 3rem 1rem 1rem;
    margin-top: auto;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
    color: var(--primary-light);
}

.footer-section p {
    opacity: 0.8;
    line-height: 1.6;
}

.footer-section .owner {
    font-size: 0.9rem;
    margin-top: 0.5rem;
}

.footer-section a {
    display: block;
    color: white;
    text-decoration: none;
    opacity: 0.8;
    margin-bottom: 0.5rem;
    transition: var(--transition);
}

.footer-section a:hover {
    opacity: 1;
    color: var(--primary-light);
}

.footer-bottom {
    text-align: center;
    padding-top: 1rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    opacity: 0.7;
}

.legal-page {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    max-width: 900px;
    margin: 0 auto;
}

.legal-page h1 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.legal-page h2 {
    color: var(--secondary-color);
    margin-top: 2rem;
    margin-bottom: 1rem;
}

.legal-page p, .legal-page ul {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.7;
}

.legal-page ul {
    padding-left: 2rem;
}

.legal-page li {
    margin-bottom: 0.5rem;
}

.contact-info {
    background-color: #FAFAFA;
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1rem 0;
}

.contact-info p {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.success-message {
    background-color: #4CAF50;
    color: white;
    padding: 1rem;
    border-radius: 8px;
    margin: 1rem 0;
    text-align: center;
}

.error-message {
    background-color: #F44336;
    color: white;
    padding: 1rem;
    border-radius: 8px;
    margin: 1rem 0;
    text-align: center;
}

.notice-box {
    background-color: #FFF9C4;
    border-left: 4px solid #FBC02D;
    padding: 1rem;
    margin: 1rem 0;
    border-radius: 4px;
}

.notice-box p {
    color: var(--text-primary);
    margin: 0;
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }

    .tagline {
        font-size: 1rem;
    }

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

    .footer-content {
        grid-template-columns: 1fr;
    }

    .navigation-buttons {
        flex-direction: column;
    }

    .btn-secondary {
        width: 100%;
    }
}