/* Main Styles */
:root {
    --primary-color: #2c3e50;
    --secondary-color: #20c997;
    --accent-color: #3bc9db;
    --light-bg: #f8f9fa;
    --dark-text: #212529;
    --light-text: #f8f9fa;
    --gray-text: #6c757d;
    --border-radius: 10px;
    --shadow-sm: 0 2px 5px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 5px 10px -1px rgba(0,0,0,0.1), 0 2px 4px -2px rgba(0,0,0,0.06);
    --shadow-lg: 0 12px 20px -3px rgba(0,0,0,0.12), 0 4px 8px -4px rgba(0,0,0,0.07);
    --transition: all 0.3s ease;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.7;
    color: var(--dark-text);
    background-color: var(--light-bg);
    overflow-x: hidden;
    background-image: linear-gradient(to right, rgba(248, 249, 250, 0.8), rgba(233, 236, 239, 0.8));
}

.container {
    width: 95%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header & Navigation */
header {
    background-color: var(--primary-color);
    color: var(--light-text);
    padding: 1.2rem 0;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 3px solid var(--secondary-color);
    background-image: linear-gradient(to right, var(--primary-color), #34495e);
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 1rem;
}

.logo {
    font-size: 1.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: -0.5px;
    background: linear-gradient(120deg, var(--light-text), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links li {
    margin: 0;
}

.nav-links a {
    color: var(--light-text);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem;
    position: relative;
    transition: var(--transition);
}

.nav-links a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 2px;
    background-color: var(--secondary-color);
    transition: var(--transition);
}

.nav-links a:hover {
    color: var(--secondary-color);
}

.nav-links a:hover::after,
.nav-links a.active::after {
    width: 100%;
}

.nav-links a.active {
    color: var(--secondary-color);
    font-weight: 600;
}

.nav-links.auth-links {
    gap: 1rem;
    margin-left: auto;
}

.btn-signup {
    background: var(--secondary-color);
    color: white !important;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    transition: var(--transition);
}

.btn-signup:hover {
    background: #12b886;
    transform: translateY(-2px);
}

.btn-signup::after {
    display: none;
}

.language-selector {
    margin: 0.5rem 1rem;
    text-align: right;
}

.lang-btn {
    padding: 0.4rem 0.8rem;
    background: transparent;
    border: 2px solid var(--secondary-color);
    color: var(--light-text);
    border-radius: var(--border-radius);
    text-decoration: none;
    margin-left: 0.5rem;
    font-size: 0.9rem;
    font-weight: 600;
    transition: var(--transition);
}

.lang-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 2px 8px rgba(32, 201, 151, 0.4);
}

.lang-btn.active {
    background-color: var(--secondary-color);
    color: var(--light-text);
    border-color: var(--secondary-color);
}

/* Content Styles */
main {
    padding: 3rem 0;
}

h1 {
    font-size: 2.4rem;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    font-weight: 700;
    letter-spacing: -0.5px;
    position: relative;
    display: inline-block;
}

h1::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -8px;
    width: 80px;
    height: 4px;
    background: linear-gradient(to right, var(--secondary-color), var(--accent-color));
    border-radius: 2px;
}

h2 {
    font-size: 2rem;
    margin: 2rem 0 1.25rem;
    color: var(--primary-color);
    font-weight: 700;
    letter-spacing: -0.3px;
}

h3 {
    font-size: 1.6rem;
    margin: 1.5rem 0 1rem;
    color: var(--secondary-color);
    font-weight: 600;
}

p {
    margin-bottom: 1.25rem;
    color: var(--dark-text);
    line-height: 1.7;
}

/* Calculator Containers */
.calculator-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    margin-top: 2.5rem;
    gap: 2.5rem;
}

.input-section, .results-section {
    flex: 1;
    min-width: 300px;
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-top: 4px solid var(--secondary-color);
}

.input-section:hover, .results-section:hover {
    box-shadow: var(--shadow-lg);
}

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

label {
    display: block;
    margin-bottom: 0.625rem;
    font-weight: 600;
    color: var(--primary-color);
}

input, select {
    width: 100%;
    padding: 0.9rem 1rem;
    border: 1px solid #e2e8f0;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    font-family: inherit;
}

input:focus, select:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(217, 119, 6, 0.2);
}

small {
    display: block;
    color: var(--gray-text);
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

/* Buttons */
.btn-primary {
    display: inline-block;
    background-color: var(--secondary-color);
    color: white;
    padding: 0.875rem 1.75rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: var(--transition);
    text-decoration: none;
    text-align: center;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.btn-primary:hover {
    background-color: #12b886;
    transform: translateY(-2px);
    box-shadow: 0 4px 10px rgba(32, 201, 151, 0.4);
}

/* Result Cards */
.result-card {
    background-color: var(--light-bg);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border-left: 4px solid var(--secondary-color);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.result-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.result-value {
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0.75rem 0;
    letter-spacing: -0.5px;
}

.result-range {
    font-size: 1.6rem;
    color: var(--primary-color);
    margin: 0.75rem 0;
    font-weight: 600;
}

.result-description {
    color: var(--gray-text);
    font-size: 0.95rem;
    line-height: 1.6;
    margin-top: 0.75rem;
}

.result-info, .result-recommendation {
    margin-bottom: 1.5rem;
    padding: 1.25rem;
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-sm);
    border-left: 4px solid var(--secondary-color);
}

/* Status Colors */
.speed-slow {
    border-left-color: #fa5252;
}

.speed-optimal {
    border-left-color: #12b886;
}

.speed-fast {
    border-left-color: #1098ad;
}

.speed-slow span {
    color: #fa5252;
}

.speed-optimal span {
    color: #12b886;
}

.speed-fast span {
    color: #1098ad;
}

/* Speed Gauge */
.speed-gauge {
    margin-top: 2.5rem;
    text-align: center;
}

/* Status Indicators */
.status {
    padding: 0.4rem 0.8rem;
    border-radius: var(--border-radius);
    display: inline-block;
    font-weight: 600;
    font-size: 0.9rem;
}

.status-slow {
    background-color: #ffe3e3;
    color: #fa5252;
    border: 1px solid rgba(250, 82, 82, 0.3);
}

.status-optimal {
    background-color: #d3f9ee;
    color: #12b886;
    border: 1px solid rgba(18, 184, 134, 0.3);
}

.status-fast {
    background-color: #e3fafc;
    color: #1098ad;
    border: 1px solid rgba(16, 152, 173, 0.3);
}

/* VFD Result */
.vfd-result {
    border-left-color: #748ffc;
    background-color: #e5edff;
}

/* Steel Info Container */
.steel-info-container {
    max-width: 1080px;
    margin: 0 auto;
    padding: 1.5rem;
}

.steel-card {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-top: 4px solid var(--secondary-color);
    border-bottom: 1px solid rgba(0,0,0,0.05);
    background: linear-gradient(to bottom, #ffffff, #f9fafc);
}

.steel-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.steel-card h3 {
    color: var(--primary-color);
    border-bottom: 2px solid var(--secondary-color);
    padding-bottom: 0.75rem;
    margin-bottom: 1.5rem;
    font-size: 1.6rem;
    font-weight: 700;
}

.properties-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.property {
    display: flex;
    flex-direction: column;
}

.property-name {
    font-weight: 600;
    margin-bottom: 0.625rem;
    color: var(--primary-color);
}

.property-bar {
    height: 0.85rem;
    background-color: #edf2f7;
    border-radius: 0.5rem;
    overflow: hidden;
    box-shadow: inset 0 1px 3px rgba(0,0,0,0.15);
    margin-bottom: 0.5rem;
}

.property-value, .property-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
    border-radius: 0.375rem;
    transition: width 0.8s ease-out;
    min-width: 5px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.grinding-notes {
    margin-top: 1.5rem;
    padding: 1.25rem;
    background-color: #fffbeb;
    border-left: 4px solid var(--accent-color);
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
    line-height: 1.6;
}

.back-link {
    display: inline-flex;
    align-items: center;
    margin: 1.5rem 0;
    color: var(--primary-color);
    background-color: rgba(32, 201, 151, 0.15);
    text-decoration: none;
    font-weight: 700;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    transition: var(--transition);
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.back-link:hover {
    color: var(--primary-color);
    background-color: rgba(32, 201, 151, 0.25);
    transform: translateX(-5px);
    box-shadow: 0 2px 6px rgba(0,0,0,0.15);
}

.back-link::before {
    content: '←';
    margin-right: 0.8rem;
    font-size: 1.3rem;
    font-weight: 800;
}

/* Tool Cards */
.welcome-section {
    margin-top: 2rem;
}

.tool-cards {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2.5rem;
}

.tool-card {
    background-color: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-top: 4px solid var(--secondary-color);
    display: flex;
    flex-direction: column;
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.tool-card h2 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin: 0 0 1rem;
    font-weight: 700;
}

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

/* Footer */
footer {
    text-align: center;
    padding: 2.5rem 0;
    background-color: var(--primary-color);
    color: var(--light-text);
    margin-top: 3rem;
    border-top: 3px solid var(--secondary-color);
    background-image: linear-gradient(to right, var(--primary-color), #34495e);
}

footer p {
    font-size: 1rem;
    opacity: 0.9;
    color: var(--light-text);
    margin-bottom: 0;
}

/* Mobile Menu Button */
.mobile-menu-button {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 22px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 10;
}

.mobile-menu-button span {
    display: block;
    height: 3px;
    width: 100%;
    background-color: var(--light-text);
    border-radius: 3px;
    transition: var(--transition);
}

.mobile-menu-button.active span:nth-child(1) {
    transform: translateY(9px) rotate(45deg);
    background-color: var(--accent-color);
}

.mobile-menu-button.active span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-button.active span:nth-child(3) {
    transform: translateY(-9px) rotate(-45deg);
    background-color: var(--accent-color);
}

/* Responsive Styles */
@media (max-width: 768px) {
    .calculator-container {
        flex-direction: column;
    }

    nav {
        position: relative;
        justify-content: space-between;
        padding: 1rem;
        flex-wrap: wrap;
    }

    .mobile-menu-button {
        display: flex;
    }

    .nav-links {
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: #2c3e50;
        display: none;
        box-shadow: 0 4px 6px rgba(0,0,0,0.1);
        z-index: 100;
        margin-left: 0;
    }

    .nav-links.show {
        display: flex;
    }

    .nav-links.auth-links {
        margin-left: 0;
    }

    .nav-links li {
        margin: 0;
        text-align: center;
        padding: 1rem 0;
        border-bottom: 1px solid rgba(255,255,255,0.1);
    }

    .nav-links li:last-child {
        border-bottom: none;
    }

    .btn-signup {
        display: block;
        width: auto;
        margin: 0 auto;
    }

    .language-selector {
        text-align: center;
        margin: 0.75rem 0;
    }
}

/* Errors */
.error {
    color: #e74c3c;
    padding: 1rem;
    background-color: #ffecec;
    border-radius: 4px;
    margin: 1rem 0;
}

/* About Page Styles */
.about-page {
    max-width: 1000px;
    margin: 0 auto;
}

.about-section {
    margin-bottom: 3rem;
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.about-section h2 {
    background-color: var(--primary-color);
    color: var(--light-text);
    margin: 0;
    padding: 1.25rem 1.5rem;
    font-size: 1.5rem;
    border-bottom: 3px solid var(--secondary-color);
}

.about-content {
    padding: 1.5rem 2rem;
}

.about-content h3 {
    color: var(--secondary-color);
    font-size: 1.3rem;
    margin: 1.5rem 0 0.75rem;
}

.about-content h3:first-child {
    margin-top: 0;
}

.about-content p {
    margin-bottom: 1rem;
    line-height: 1.7;
}

.about-content ul {
    margin-bottom: 1.5rem;
    padding-left: 1.5rem;
}

.about-content ul li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.disclaimer {
    border-left: 4px solid #fa5252;
    background-color: #fff5f5;
}

.disclaimer p strong {
    color: #fa5252;
}

.about-content a {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.about-content a:hover {
    color: var(--primary-color);
    text-decoration: underline;
}
/* ===============================================
   STEEL SELECTOR - MODERN REDESIGN
   =============================================== */

/* Page Header */
.page-header {
    text-align: center;
    margin-bottom: 3rem;
    padding: 2rem 0;
}

.page-header h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
}

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

.page-subtitle {
    font-size: 1.1rem;
    color: var(--gray-text);
    max-width: 600px;
    margin: 0 auto;
}

/* Main Layout */
.steel-selector-layout {
    display: grid;
    grid-template-columns: 380px 1fr;
    gap: 2rem;
    align-items: start;
}

/* Sidebar */
.selector-sidebar {
    position: sticky;
    top: 100px;
}

.selector-form-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    border-top: 4px solid var(--secondary-color);
}

.selector-form-card h2 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Modern Form Groups */
.form-group-modern {
    margin-bottom: 2rem;
}

.form-group-modern:last-of-type {
    margin-bottom: 1.5rem;
}

.slider-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}

.slider-header label {
    font-weight: 600;
    color: var(--primary-color);
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.slider-value {
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-weight: 700;
    font-size: 0.9rem;
    min-width: 35px;
    text-align: center;
}

/* Modern Slider */
.modern-slider {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 8px;
    border-radius: 5px;
    background: linear-gradient(to right, #e9ecef 0%, var(--secondary-color) 50%, var(--accent-color) 100%);
    outline: none;
    opacity: 0.8;
    transition: opacity 0.2s;
}

.modern-slider:hover {
    opacity: 1;
}

.modern-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: white;
    border: 3px solid var(--secondary-color);
    cursor: pointer;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    transition: all 0.2s;
}

.modern-slider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    border-color: var(--accent-color);
}

.modern-slider::-moz-range-thumb {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: white;
    border: 3px solid var(--secondary-color);
    cursor: pointer;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    transition: all 0.2s;
}

.modern-slider::-moz-range-thumb:hover {
    transform: scale(1.2);
    border-color: var(--accent-color);
}

.slider-labels {
    display: flex;
    justify-content: space-between;
    margin-top: 0.5rem;
    font-size: 0.85rem;
    color: var(--gray-text);
}

/* Modern Select */
.modern-select {
    width: 100%;
    padding: 0.85rem;
    border: 2px solid #e9ecef;
    border-radius: var(--border-radius);
    font-size: 0.95rem;
    background: white;
    cursor: pointer;
    transition: var(--transition);
    color: var(--dark-text);
    font-weight: 500;
}

.modern-select:hover {
    border-color: var(--secondary-color);
}

.modern-select:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(32, 201, 151, 0.1);
}

/* Button Group */
.button-group {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
}

.btn-large {
    flex: 1;
    padding: 1rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    border: none;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.btn-primary.btn-large {
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    color: white;
}

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

.btn-secondary.btn-large {
    background: white;
    color: var(--gray-text);
    border: 2px solid #e9ecef;
}

.btn-secondary.btn-large:hover {
    background: #f8f9fa;
    border-color: var(--gray-text);
}

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

/* Results Section */
.results-main {
    min-height: 500px;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #e9ecef;
}

.results-header h2 {
    font-size: 1.8rem;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.results-count {
    background: var(--secondary-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: 600;
    font-size: 0.9rem;
}

/* No Results Card */
.no-results-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 4rem 2rem;
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 2px dashed #e9ecef;
}

.no-results-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.no-results-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.75rem;
}

.no-results-text {
    font-size: 1.1rem;
    color: var(--gray-text);
    max-width: 500px;
    margin: 0 auto;
}

/* Steel Results Grid */
.steel-results {
    display: grid;
    gap: 1.5rem;
}

/* Updated Steel Card */
.steel-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-left: 5px solid var(--secondary-color);
    position: relative;
    overflow: hidden;
}

.steel-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(to right, var(--secondary-color), var(--accent-color));
}

.steel-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.steel-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid #f8f9fa;
}

.steel-card-header h3 {
    font-size: 1.8rem;
    color: var(--primary-color);
    margin: 0;
    border: none;
    padding: 0;
}

.match-percentage {
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 25px;
    font-weight: 700;
    font-size: 1.1rem;
    box-shadow: 0 2px 8px rgba(32, 201, 151, 0.3);
}

/* Steel Properties Bars */
.steel-properties {
    display: grid;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.property {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.property-name {
    font-weight: 600;
    color: var(--primary-color);
    font-size: 0.95rem;
}

.property-bar {
    height: 12px;
    background: #f1f3f5;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: inset 0 1px 3px rgba(0,0,0,0.1);
}

.property-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--secondary-color), var(--accent-color));
    border-radius: 10px;
    transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 4px rgba(32, 201, 151, 0.3);
}

/* Steel Description */
.steel-description {
    background: #f8f9fa;
    padding: 1.25rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    border-left: 4px solid var(--accent-color);
}

.steel-description p {
    color: var(--dark-text);
    line-height: 1.7;
    margin: 0;
}

/* Steel Properties List */
.steel-properties-list {
    margin-top: 1.5rem;
}

.steel-properties-list h4 {
    font-size: 1.1rem;
    color: var(--primary-color);
    margin-bottom: 0.75rem;
}

.steel-properties-list ul {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.steel-properties-list li {
    background: linear-gradient(135deg, #f8f9fa, #e9ecef);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    color: var(--dark-text);
    border: 1px solid #dee2e6;
    transition: var(--transition);
}

.steel-properties-list li:hover {
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    color: white;
    border-color: var(--secondary-color);
    transform: translateY(-2px);
}

/* Loading State */
.loading {
    text-align: center;
    padding: 3rem;
    font-size: 1.2rem;
    color: var(--gray-text);
}

.error {
    background: #ffe5e5;
    color: #d32f2f;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    text-align: center;
    border-left: 4px solid #d32f2f;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .steel-selector-layout {
        grid-template-columns: 1fr;
    }
    
    .selector-sidebar {
        position: static;
    }
}

@media (max-width: 768px) {
    .page-header h1 {
        font-size: 2rem;
    }
    
    .page-subtitle {
        font-size: 1rem;
    }
    
    .selector-form-card {
        padding: 1.5rem;
    }
    
    .button-group {
        flex-direction: column;
    }
    
    .steel-card {
        padding: 1.5rem;
    }
    
    .steel-card-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }
    
    .match-percentage {
        align-self: flex-start;
    }
}

/* ===============================================
   CALCULATORS - MODERN REDESIGN
   =============================================== */

/* Calculator Layout (same as steel selector) */
.calculator-layout {
    display: grid;
    grid-template-columns: 380px 1fr;
    gap: 2rem;
    align-items: start;
}

.calculator-sidebar {
    position: sticky;
    top: 100px;
}

.calculator-form-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    border-top: 4px solid var(--accent-color);
}

.calculator-form-card h2 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Calculator Form Groups */
.form-group-calc {
    margin-bottom: 1.75rem;
}

.form-group-calc label {
    font-weight: 600;
    color: var(--primary-color);
    font-size: 0.95rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.75rem;
}

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

.input-with-value {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.calc-input {
    flex: 1;
    padding: 0.75rem;
    border: 2px solid #e9ecef;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    color: var(--primary-color);
    transition: var(--transition);
}

.calc-input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(59, 201, 219, 0.1);
}

.input-unit {
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    color: white;
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius);
    font-weight: 700;
    font-size: 0.9rem;
    min-width: 50px;
    text-align: center;
}

/* Grind Visualization Card */
.grind-visualization-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 1.5rem;
    border-left: 5px solid var(--accent-color);
}

.grind-visualization-card h3 {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
}

.grind-visualization-card canvas {
    display: block;
    margin: 0 auto;
    background: #f8f9fa;
    border-radius: 8px;
    padding: 1rem;
}

/* Grind Results Data */
.grind-results-data {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    border-left: 5px solid var(--secondary-color);
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid #f1f3f5;
    transition: var(--transition);
}

.result-item:last-child {
    border-bottom: none;
}

.result-item:hover {
    background: #f8f9fa;
}

.result-label {
    font-weight: 600;
    color: var(--gray-text);
    font-size: 0.95rem;
}

.result-value {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary-color);
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Grind Notes */
.grind-notes {
    background: linear-gradient(135deg, #e3f2fd, #f1f8e9);
    border-left: 4px solid var(--accent-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-top: 1.5rem;
}

.grind-notes h4 {
    color: var(--primary-color);
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.grind-notes h4::before {
    content: '💡';
    font-size: 1.2rem;
}

.grind-notes p {
    color: var(--dark-text);
    line-height: 1.7;
    margin: 0;
}

/* Speed Calculator Specific */
.speed-results-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    margin-bottom: 1.5rem;
}

.speed-gauge {
    background: linear-gradient(to right, #ff6b6b 0%, #ffd93d 30%, #6bcf7f 60%, #ff6b6b 100%);
    height: 30px;
    border-radius: 15px;
    position: relative;
    margin: 2rem 0;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.2);
}

.speed-indicator {
    position: absolute;
    top: -10px;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-weight: 700;
    box-shadow: var(--shadow);
    transition: left 0.5s ease;
}

.speed-indicator::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 0;
    border-left: 8px solid transparent;
    border-right: 8px solid transparent;
    border-top: 8px solid var(--primary-color);
}

.speed-zones {
    display: flex;
    justify-content: space-between;
    margin-top: 0.5rem;
    font-size: 0.85rem;
    color: var(--gray-text);
}

.speed-zone {
    flex: 1;
    text-align: center;
    padding: 0.5rem;
}

.speed-zone.optimal {
    font-weight: 700;
    color: var(--secondary-color);
}

/* Recommendations Grid */
.recommendations-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.recommendation-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--shadow-sm);
    border-top: 3px solid var(--accent-color);
    transition: var(--transition);
}

.recommendation-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.recommendation-card h4 {
    color: var(--primary-color);
    margin-bottom: 0.75rem;
    font-size: 1.1rem;
}

.recommendation-card .value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--secondary-color);
    display: block;
    margin: 0.5rem 0;
}

.recommendation-card .description {
    color: var(--gray-text);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* Warning/Info Boxes */
.info-box {
    background: linear-gradient(135deg, #e3f2fd, #f1f8e9);
    border-left: 4px solid #2196f3;
    border-radius: var(--border-radius);
    padding: 1.25rem;
    margin: 1.5rem 0;
}

.warning-box {
    background: linear-gradient(135deg, #fff3e0, #ffe0b2);
    border-left: 4px solid #ff9800;
    border-radius: var(--border-radius);
    padding: 1.25rem;
    margin: 1.5rem 0;
}

.info-box p, .warning-box p {
    margin: 0;
    color: var(--dark-text);
    line-height: 1.7;
}

.info-box::before {
    content: 'ℹ️ ';
    font-size: 1.2rem;
}

.warning-box::before {
    content: '⚠️ ';
    font-size: 1.2rem;
}

/* Responsive Calculators */
@media (max-width: 1024px) {
    .calculator-layout {
        grid-template-columns: 1fr;
    }
    
    .calculator-sidebar {
        position: static;
    }
    
    .grind-visualization-card canvas {
        max-width: 100%;
        height: auto;
    }
}

@media (max-width: 768px) {
    .calculator-form-card {
        padding: 1.5rem;
    }
    
    .recommendations-grid {
        grid-template-columns: 1fr;
    }
    
    .result-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }
    
    .result-value {
        font-size: 1.5rem;
    }
}