/* ==========================================================================
   DiabetesDetect — Production UI Design System
   ========================================================================== */

:root {
    --color-primary: #0d9488;
    --color-primary-dark: #0f766e;
    --color-primary-light: #ccfbf1;
    --color-primary-subtle: #f0fdfa;

    --color-success: #059669;
    --color-success-bg: #ecfdf5;
    --color-success-border: #a7f3d0;

    --color-warning: #d97706;
    --color-warning-bg: #fffbeb;
    --color-warning-border: #fde68a;

    --color-danger: #dc2626;
    --color-danger-bg: #fef2f2;
    --color-danger-border: #fecaca;

    --color-text: #0f172a;
    --color-text-secondary: #475569;
    --color-text-muted: #94a3b8;

    --color-bg: #f8fafc;
    --color-surface: #ffffff;
    --color-border: #e2e8f0;
    --color-border-focus: #0d9488;

    --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.08), 0 2px 4px -2px rgba(15, 23, 42, 0.05);
    --shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, 0.08), 0 4px 6px -4px rgba(15, 23, 42, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(15, 23, 42, 0.08), 0 8px 10px -6px rgba(15, 23, 42, 0.04);

    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --transition: 0.2s ease;
}

/* Reset & Base
   ========================================================================== */

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

img, svg {
    display: block;
    max-width: 100%;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition);
}

a:hover {
    color: var(--color-primary-dark);
}

/* Accessibility
   ========================================================================== */

.skip-link {
    position: absolute;
    top: -100%;
    left: 16px;
    z-index: 1000;
    padding: 8px 16px;
    background: var(--color-primary);
    color: #fff;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

.skip-link:focus {
    top: 16px;
}

:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Layout
   ========================================================================== */

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

main {
    flex: 1;
}

/* Header
   ========================================================================== */

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--color-text);
    text-decoration: none;
}

.brand:hover {
    color: var(--color-text);
}

.brand-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    border-radius: var(--radius-md);
    color: #fff;
}

.brand-icon svg {
    width: 24px;
    height: 24px;
}

.brand-text {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

.brand-name {
    font-size: 1.125rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.brand-tagline {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

.header-nav {
    display: flex;
    gap: 8px;
}

.nav-link {
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-secondary);
    transition: background var(--transition), color var(--transition);
}

.nav-link:hover,
.nav-link.active {
    background: var(--color-primary-subtle);
    color: var(--color-primary-dark);
}

/* Hero Section
   ========================================================================== */

.hero {
    padding: 48px 0 64px;
    background: linear-gradient(180deg, var(--color-primary-subtle) 0%, var(--color-bg) 100%);
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1.1fr;
    gap: 48px;
    align-items: start;
}

.hero-content {
    padding-top: 24px;
}

.badge {
    display: inline-block;
    padding: 6px 14px;
    background: var(--color-primary-light);
    color: var(--color-primary-dark);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: 100px;
    margin-bottom: 20px;
}

.hero h1 {
    font-size: clamp(2rem, 4vw, 2.75rem);
    font-weight: 700;
    line-height: 1.15;
    letter-spacing: -0.03em;
    margin-bottom: 16px;
    color: var(--color-text);
}

.hero-lead {
    font-size: 1.0625rem;
    color: var(--color-text-secondary);
    margin-bottom: 28px;
    max-width: 480px;
}

.hero-features {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.hero-features li {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-text-secondary);
}

.hero-features svg {
    width: 20px;
    height: 20px;
    color: var(--color-success);
    flex-shrink: 0;
}

/* Form Card
   ========================================================================== */

.form-card {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--color-border);
    overflow: hidden;
}

.form-card-header {
    padding: 28px 32px 0;
}

.form-card-header h2 {
    font-size: 1.375rem;
    font-weight: 700;
    margin-bottom: 6px;
    letter-spacing: -0.02em;
}

.form-card-header p {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

.form-card form {
    padding: 24px 32px 32px;
}

.alert {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 20px 32px 0;
    padding: 14px 16px;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
}

.alert svg {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.alert-error {
    background: var(--color-danger-bg);
    color: var(--color-danger);
    border: 1px solid var(--color-danger-border);
}

.form-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.form-group-full {
    grid-column: 1 / -1;
}

.form-group label {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-text);
    letter-spacing: 0.01em;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.field {
    width: 100%;
    padding: 12px 14px;
    font-family: inherit;
    font-size: 0.9375rem;
    color: var(--color-text);
    background: var(--color-bg);
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: border-color var(--transition), box-shadow var(--transition), background var(--transition);
}

.field::placeholder {
    color: var(--color-text-muted);
}

.field:hover {
    border-color: #cbd5e1;
}

.field:focus {
    outline: none;
    border-color: var(--color-border-focus);
    background: var(--color-surface);
    box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.12);
}

.field.field-error {
    border-color: var(--color-danger);
    background: var(--color-danger-bg);
}

.field.field-error:focus {
    box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.12);
}

.input-unit {
    position: absolute;
    right: 14px;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--color-text-muted);
    pointer-events: none;
    background: transparent;
}

.input-wrapper .field {
    padding-right: 72px;
}

.input-wrapper .field:not([type="number"]) {
    padding-right: 14px;
}

.field-hint {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    line-height: 1.4;
}

.field-error-msg {
    font-size: 0.75rem;
    color: var(--color-danger);
    font-weight: 500;
}

/* Buttons
   ========================================================================== */

.form-actions {
    display: flex;
    gap: 12px;
    margin-top: 28px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 24px;
    font-family: inherit;
    font-size: 0.9375rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
    text-decoration: none;
}

.btn:active {
    transform: scale(0.98);
}

.btn-primary {
    flex: 1;
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    color: #fff;
    box-shadow: 0 2px 8px rgba(13, 148, 136, 0.3);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--color-primary-dark), #115e59);
    color: #fff;
    box-shadow: 0 4px 12px rgba(13, 148, 136, 0.4);
}

.btn-secondary {
    background: var(--color-bg);
    color: var(--color-text-secondary);
    border: 1.5px solid var(--color-border);
}

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

.btn-block {
    width: 100%;
}

.btn-loader {
    display: none;
    align-items: center;
    gap: 8px;
}

.btn.loading .btn-text {
    display: none;
}

.btn.loading .btn-loader {
    display: inline-flex;
}

.spinner {
    width: 20px;
    height: 20px;
    animation: spin 0.8s linear infinite;
}

.spinner circle {
    stroke-linecap: round;
    animation: dash 1.5s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

@keyframes dash {
    0% { stroke-dashoffset: 31.4; }
    50% { stroke-dashoffset: 0; }
    100% { stroke-dashoffset: -31.4; }
}

/* Info Section
   ========================================================================== */

.info-section {
    padding: 80px 0;
    background: var(--color-surface);
}

.section-header {
    text-align: center;
    max-width: 560px;
    margin: 0 auto 48px;
}

.section-header h2 {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 12px;
}

.section-header p {
    color: var(--color-text-secondary);
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.step-card {
    padding: 32px 28px;
    background: var(--color-bg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    transition: box-shadow var(--transition), transform var(--transition);
}

.step-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.step-number {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--color-primary);
    color: #fff;
    font-size: 1rem;
    font-weight: 700;
    border-radius: var(--radius-md);
    margin-bottom: 20px;
}

.step-card h3 {
    font-size: 1.0625rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.step-card p {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* Metrics Section
   ========================================================================== */

.metrics-section {
    padding: 48px 0 80px;
}

.metrics-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.metric-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 28px 20px;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}

.metric-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.03em;
    line-height: 1;
    margin-bottom: 8px;
}

.metric-label {
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-text-muted);
    text-align: center;
}

/* Result Page
   ========================================================================== */

.result-section {
    padding: 48px 0 80px;
}

.result-container {
    display: grid;
    grid-template-columns: 1.4fr 1fr;
    gap: 32px;
    align-items: start;
}

.result-card {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: 40px;
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
}

.result-card.result-negative {
    border-top: 4px solid var(--color-success);
}

.result-card.result-positive {
    border-top: 4px solid var(--color-danger);
}

.result-icon {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
}

.result-negative .result-icon {
    background: var(--color-success-bg);
    color: var(--color-success);
}

.result-positive .result-icon {
    background: var(--color-danger-bg);
    color: var(--color-danger);
}

.result-icon svg {
    width: 32px;
    height: 32px;
}

.result-badge {
    display: inline-block;
    padding: 6px 14px;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    border-radius: 100px;
    margin-bottom: 16px;
}

.risk-low {
    background: var(--color-success-bg);
    color: var(--color-success);
}

.risk-moderate {
    background: var(--color-warning-bg);
    color: var(--color-warning);
}

.risk-high {
    background: var(--color-danger-bg);
    color: var(--color-danger);
}

.result-header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 12px;
    line-height: 1.25;
}

.result-summary {
    font-size: 1rem;
    color: var(--color-text-secondary);
    margin-bottom: 32px;
}

.confidence-section {
    margin-bottom: 32px;
    padding: 24px;
    background: var(--color-bg);
    border-radius: var(--radius-lg);
}

.confidence-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-secondary);
}

.confidence-value {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text);
}

.confidence-bar {
    height: 10px;
    background: var(--color-border);
    border-radius: 100px;
    overflow: hidden;
}

.confidence-fill {
    height: 100%;
    border-radius: 100px;
    transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.confidence-fill.risk-low { background: var(--color-success); }
.confidence-fill.risk-moderate { background: var(--color-warning); }
.confidence-fill.risk-high { background: var(--color-danger); }

.recommendations h2 {
    font-size: 1.0625rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.recommendations ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.recommendations li {
    position: relative;
    padding-left: 24px;
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    line-height: 1.5;
}

.recommendations li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 8px;
    width: 8px;
    height: 8px;
    background: var(--color-primary);
    border-radius: 50%;
}

/* Input Summary Sidebar
   ========================================================================== */

.input-summary {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    padding: 32px;
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 96px;
}

.input-summary h2 {
    font-size: 1.0625rem;
    font-weight: 600;
    margin-bottom: 20px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--color-border);
}

.summary-list {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    border-bottom: 1px solid var(--color-border);
}

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

.summary-item dt {
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

.summary-item dd {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--color-text);
}

.summary-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 24px;
}

/* Footer
   ========================================================================== */

.site-footer {
    background: var(--color-text);
    color: #cbd5e1;
    padding: 32px 0;
    margin-top: auto;
}

.footer-inner {
    display: flex;
    flex-direction: column;
    gap: 16px;
    text-align: center;
}

.footer-disclaimer {
    font-size: 0.8125rem;
    line-height: 1.6;
    max-width: 720px;
    margin: 0 auto;
}

.footer-disclaimer strong {
    color: #e2e8f0;
}

.footer-meta {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-size: 0.75rem;
    color: #64748b;
}

.footer-divider {
    color: #475569;
}

/* Print Styles
   ========================================================================== */

@media print {
    .site-header,
    .site-footer,
    .summary-actions,
    .skip-link {
        display: none !important;
    }

    body {
        background: #fff;
    }

    .result-section {
        padding: 0;
    }

    .result-container {
        grid-template-columns: 1fr;
    }

    .result-card,
    .input-summary {
        box-shadow: none;
        border: 1px solid #ccc;
    }
}

/* Responsive
   ========================================================================== */

@media (max-width: 1024px) {
    .hero-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .hero-content {
        text-align: center;
        padding-top: 0;
    }

    .hero-lead {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-features {
        align-items: center;
    }

    .result-container {
        grid-template-columns: 1fr;
    }

    .input-summary {
        position: static;
    }

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

@media (max-width: 768px) {
    .header-inner {
        height: 64px;
    }

    .brand-tagline {
        display: none;
    }

    .header-nav {
        display: none;
    }

    .hero {
        padding: 32px 0 48px;
    }

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

    .form-card-header,
    .form-card form {
        padding-left: 20px;
        padding-right: 20px;
    }

    .alert {
        margin-left: 20px;
        margin-right: 20px;
    }

    .form-actions {
        flex-direction: column;
    }

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

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

    .result-card {
        padding: 28px 24px;
    }

    .input-summary {
        padding: 24px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

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