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

:root {
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --dark-gradient: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
    --light-bg: #f8f9fa;
    --card-bg: #ffffff;
    --text-primary: #2d3748;
    --text-secondary: #718096;
    --border-color: #e2e8f0;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.2);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--primary-gradient);
    min-height: 100vh;
    padding: 20px;
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

/* Header Styles */
.header {
    text-align: center;
    margin-bottom: 40px;
    color: white;
}

.title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.title-icon {
    font-size: 3.5rem;
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.subtitle {
    font-size: 1.2rem;
    font-weight: 300;
    opacity: 0.95;
}

/* Main Content */
.main-content {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.calculator-card {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 40px;
    box-shadow: var(--shadow-xl);
    backdrop-filter: blur(10px);
}

/* Input Section */
.input-section {
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.input-label {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.label-icon {
    font-size: 1.2rem;
}

/* Radio Group */
.radio-group {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.radio-label {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background: var(--light-bg);
    border: 2px solid var(--border-color);
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-primary);
}

.radio-label:hover {
    border-color: #667eea;
    background: white;
}

.radio-label input[type="radio"] {
    margin: 0;
    cursor: pointer;
}

.radio-label input[type="radio"]:checked + span {
    color: #667eea;
    font-weight: 600;
}

.radio-label:has(input[type="radio"]:checked) {
    background: var(--primary-gradient);
    color: white;
    border-color: transparent;
}

/* Number Input */
.number-input,
.select-input {
    padding: 15px 20px;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    font-size: 1rem;
    font-family: inherit;
    transition: all 0.3s ease;
    background: var(--light-bg);
    color: var(--text-primary);
}

.number-input:focus,
.select-input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
    background: white;
}

.select-input {
    cursor: pointer;
}

/* Height Input Group */
.height-input-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

/* Weight Input Group */
.weight-input-group {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 10px;
}

.weight-unit {
    min-width: 80px;
}

.input-hint {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-style: italic;
}

.hint-link {
    color: #667eea;
    text-decoration: none;
    transition: opacity 0.3s ease;
}

.hint-link:hover {
    opacity: 0.8;
    text-decoration: underline;
}

.calculate-btn {
    padding: 18px 30px;
    background: var(--primary-gradient);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    box-shadow: var(--shadow-md);
    margin-top: 10px;
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.calculate-btn:active {
    transform: translateY(0);
}

.btn-icon {
    font-size: 1.3rem;
}

/* Results Section */
.results-section {
    margin-top: 40px;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hidden {
    display: none;
}

.results-header {
    text-align: center;
    margin-bottom: 30px;
}

.results-title {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--text-primary);
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Ideal Weight Section */
.ideal-weight-section {
    margin-bottom: 30px;
}

.ideal-weight-card {
    background: var(--primary-gradient);
    color: white;
    border-radius: 20px;
    padding: 40px;
    text-align: center;
    box-shadow: var(--shadow-lg);
}

.ideal-weight-card .result-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.ideal-weight-range {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.range-label {
    font-size: 1rem;
    opacity: 0.9;
    font-weight: 500;
}

.range-value {
    font-size: 3rem;
    font-weight: 700;
    line-height: 1.2;
}

.range-unit {
    font-size: 1.2rem;
    opacity: 0.9;
    font-weight: 500;
}

/* Formulas Section */
.formulas-section {
    margin-bottom: 30px;
    padding-top: 30px;
    border-top: 2px solid var(--border-color);
}

.section-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 20px;
    text-align: center;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.formulas-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
}

.formula-card {
    background: var(--light-bg);
    border-radius: 12px;
    padding: 20px;
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.formula-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-color: #667eea;
}

.formula-name {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.formula-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

/* BMI Section */
.bmi-section {
    margin-bottom: 30px;
    padding-top: 30px;
    border-top: 2px solid var(--border-color);
}

.bmi-display {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 30px;
    margin-bottom: 25px;
}

.bmi-value-card {
    background: var(--secondary-gradient);
    color: white;
    border-radius: 16px;
    padding: 30px;
    text-align: center;
    display: flex;
    flex-direction: column;
    justify-content: center;
    box-shadow: var(--shadow-md);
}

.bmi-value {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    line-height: 1;
}

.bmi-category {
    font-size: 1.2rem;
    font-weight: 500;
    opacity: 0.95;
}

.bmi-chart-container {
    background: var(--light-bg);
    border-radius: 16px;
    padding: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-sm);
}

.bmi-chart-container canvas {
    max-width: 100%;
    height: auto;
}

.bmi-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
}

.bmi-info-item {
    background: var(--light-bg);
    border-radius: 12px;
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.info-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.info-value {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* Recommendations Section */
.recommendations-section {
    margin-top: 30px;
    padding-top: 30px;
    border-top: 2px solid var(--border-color);
}

.recommendations-content {
    background: var(--light-bg);
    border-radius: 16px;
    padding: 30px;
    line-height: 1.8;
}

.recommendation-item {
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

.recommendation-item:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.recommendation-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.recommendation-title::before {
    content: "💡";
    font-size: 1.3rem;
}

.recommendation-text {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Features Section */
.features-section {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 30px;
    box-shadow: var(--shadow-lg);
}

.features-title {
    text-align: center;
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 25px;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
}

.feature-item {
    text-align: center;
    padding: 20px;
    background: var(--light-bg);
    border-radius: 12px;
    transition: all 0.3s ease;
}

.feature-item:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: 10px;
}

.feature-text {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-primary);
}

/* Content Section */
.content-section {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 40px;
    box-shadow: var(--shadow-lg);
    margin-top: 30px;
}

.content-title {
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 20px;
    text-align: center;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.content-text {
    color: var(--text-secondary);
    line-height: 1.8;
    font-size: 1rem;
}

.content-text p {
    margin-bottom: 15px;
}

.content-list {
    margin: 20px 0;
    padding-left: 30px;
    color: var(--text-secondary);
}

.content-list li {
    margin-bottom: 10px;
    line-height: 1.6;
}

/* FAQ Section */
.faq-section {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 40px;
    box-shadow: var(--shadow-lg);
    margin-top: 30px;
}

.faq-title {
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 30px;
    text-align: center;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.faq-item {
    background: var(--light-bg);
    border-radius: 12px;
    padding: 25px;
    border: 2px solid transparent;
    transition: all 0.3s ease;
}

.faq-item:hover {
    border-color: #667eea;
    box-shadow: var(--shadow-sm);
    transform: translateY(-2px);
}

.faq-question {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.faq-answer {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin: 0;
}

/* Bookmark Banner */
.bookmark-banner {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 12px;
    padding: 16px 20px;
    margin: 20px auto 30px;
    max-width: 1200px;
    box-shadow: var(--shadow-lg);
    animation: slideDown 0.5s ease;
}

.bookmark-banner-content {
    display: flex;
    align-items: center;
    gap: 15px;
    color: white;
}

.bookmark-banner-icon {
    font-size: 1.8rem;
    flex-shrink: 0;
}

.bookmark-banner-text {
    flex: 1;
    font-size: 1rem;
    line-height: 1.5;
}

.bookmark-banner-text strong {
    font-weight: 600;
}

.bookmark-banner-link {
    color: white;
    text-decoration: underline;
    font-weight: 500;
    margin-left: 8px;
    transition: opacity 0.3s ease;
}

.bookmark-banner-link:hover {
    opacity: 0.8;
}

.bookmark-banner-close {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    font-size: 1.5rem;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: all 0.3s ease;
    line-height: 1;
    padding: 0;
}

.bookmark-banner-close:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.1);
}

.bookmark-banner-close:active {
    transform: scale(0.95);
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Floating Navigation */
.floating-nav {
    position: fixed;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    background: var(--card-bg);
    border-radius: 16px;
    padding: 20px 15px;
    box-shadow: var(--shadow-xl);
    z-index: 1000;
    min-width: 140px;
    max-width: 160px;
    transition: all 0.3s ease;
    backdrop-filter: blur(10px);
    border: 2px solid rgba(255, 255, 255, 0.8);
}

.floating-nav-header {
    display: flex;
    align-items: center;
    gap: 8px;
    padding-bottom: 15px;
    margin-bottom: 15px;
    border-bottom: 2px solid var(--border-color);
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.nav-icon {
    font-size: 1.2rem;
}

.nav-title {
    font-size: 0.9rem;
}

.floating-nav-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.floating-nav-list li {
    margin: 0;
    padding: 0;
}

.nav-link {
    display: block;
    padding: 10px 12px;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 8px;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    position: relative;
    text-align: center;
}

.nav-link:hover {
    background: var(--light-bg);
    color: var(--text-primary);
    transform: translateX(-3px);
}

.nav-link.active {
    background: var(--primary-gradient);
    color: white;
    font-weight: 500;
    box-shadow: var(--shadow-md);
}

.nav-link.active::before {
    content: '';
    position: absolute;
    left: -8px;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 60%;
    background: var(--primary-gradient);
    border-radius: 0 2px 2px 0;
}

/* Hide floating nav on mobile and tablet */
@media (max-width: 1024px) {
    .floating-nav {
        display: none !important;
    }
}

/* Feedback Section */
.feedback-section {
    background: var(--card-bg);
    border-radius: 20px;
    padding: 40px;
    box-shadow: var(--shadow-lg);
    margin-top: 30px;
}

.feedback-title {
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
    text-align: center;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.feedback-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 30px;
    font-size: 1rem;
}

.feedback-form {
    max-width: 600px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 25px;
}

.form-label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.form-input,
.form-textarea {
    width: 100%;
    padding: 15px 20px;
    border: 2px solid var(--border-color);
    border-radius: 12px;
    font-size: 1rem;
    font-family: inherit;
    transition: all 0.3s ease;
    background: var(--light-bg);
    resize: vertical;
}

.form-textarea {
    min-height: 120px;
    line-height: 1.6;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
    background: white;
}

.feedback-submit-btn {
    width: 100%;
    padding: 18px 30px;
    background: var(--primary-gradient);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    box-shadow: var(--shadow-md);
    margin-top: 10px;
}

.feedback-submit-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.feedback-submit-btn:active:not(:disabled) {
    transform: translateY(0);
}

.feedback-submit-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.feedback-message {
    margin-top: 20px;
    padding: 15px 20px;
    border-radius: 12px;
    font-size: 0.95rem;
    line-height: 1.6;
    text-align: center;
    animation: fadeIn 0.3s ease;
}

.feedback-message-success {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
}

.feedback-message-error {
    background: linear-gradient(135deg, #f5576c 0%, #f093fb 100%);
    color: white;
}

/* Footer */
.footer {
    text-align: center;
    margin-top: 40px;
    padding: 20px;
    color: white;
    opacity: 0.9;
}

.footer-links {
    margin-top: 15px;
    font-size: 0.9rem;
}

.footer-link {
    color: white;
    text-decoration: none;
    opacity: 0.9;
    transition: opacity 0.3s ease;
}

.footer-link:hover {
    opacity: 1;
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .title {
        font-size: 2rem;
    }

    .title-icon {
        font-size: 2.5rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .calculator-card {
        padding: 25px;
    }

    .radio-group {
        flex-direction: column;
    }

    .radio-label {
        width: 100%;
    }

    .height-input-group {
        grid-template-columns: 1fr;
    }

    .weight-input-group {
        grid-template-columns: 1fr;
    }

    .weight-unit {
        width: 100%;
    }

    .bmi-display {
        grid-template-columns: 1fr;
    }

    .bmi-value-card {
        padding: 25px;
    }

    .bmi-value {
        font-size: 2.5rem;
    }

    .formulas-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .content-section,
    .faq-section {
        padding: 25px;
    }

    .content-title,
    .faq-title {
        font-size: 1.5rem;
    }

    .bookmark-banner {
        padding: 12px 16px;
        margin: 15px auto 20px;
    }

    .bookmark-banner-content {
        flex-wrap: wrap;
        gap: 10px;
    }

    .bookmark-banner-icon {
        font-size: 1.5rem;
    }

    .bookmark-banner-text {
        font-size: 0.9rem;
        flex-basis: calc(100% - 50px);
    }

    .bookmark-banner-close {
        width: 28px;
        height: 28px;
        font-size: 1.3rem;
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
    }

    .title {
        font-size: 1.5rem;
        flex-direction: column;
        gap: 10px;
    }

    .calculator-card {
        padding: 20px;
    }

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

    .bmi-info {
        grid-template-columns: 1fr;
    }

    .content-section,
    .faq-section {
        padding: 20px;
    }

    .content-title,
    .faq-title {
        font-size: 1.3rem;
    }

    .faq-question {
        font-size: 1.1rem;
    }
}