/* ============================================
   4×4 Treadmill — Promotional Website Styles
   Light theme with amber/yellow accents
   ============================================ */

/* --- Reset & Base --- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --color-amber: #FECA00;
    --color-amber-dark: #E0B200;
    --color-amber-light: #FFF8D6;
    --color-coral: #F48668;
    --color-bg: #F8F7FC;
    --color-white: #FFFFFF;
    --color-charcoal: #1A1A1A;
    --color-slate: #6B7280;
    --color-slate-light: #9CA3AF;
    --color-border: #E8E4F0;
    --color-success: #10B981;
    --color-error: #EF4444;
    --radius: 12px;
    --radius-lg: 20px;
    --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.08);
    --max-width: 1100px;
    --transition: 0.2s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--color-charcoal);
    background: var(--color-bg);
    line-height: 1.6;
    font-size: 16px;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

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

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

/* --- Buttons --- */
.btn {
    display: inline-block;
    padding: 14px 32px;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    border: none;
    transition: all var(--transition);
}

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

.btn-primary:hover {
    background: #333;
    color: var(--color-white);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--color-white);
    color: var(--color-charcoal);
    border: 2px solid var(--color-border);
}

.btn-secondary:hover {
    border-color: var(--color-amber);
    color: var(--color-charcoal);
    transform: translateY(-1px);
}

/* --- Header --- */
.header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(248, 247, 252, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-charcoal);
    letter-spacing: -0.02em;
}

.logo:hover {
    color: var(--color-charcoal);
}

.nav {
    display: flex;
    gap: 32px;
}

.nav a {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--color-slate);
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-charcoal);
    border-radius: 2px;
    transition: all var(--transition);
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* --- Hero --- */
.hero {
    padding: 80px 0 60px;
    background: linear-gradient(180deg, var(--color-white) 0%, var(--color-bg) 100%);
}

.hero-inner {
    display: flex;
    align-items: center;
    gap: 60px;
}

.hero-text {
    flex: 1;
}

.hero-text h1 {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: 20px;
}

.hero-subtitle {
    font-size: 1.15rem;
    color: var(--color-slate);
    line-height: 1.7;
    margin-bottom: 32px;
    max-width: 480px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.hero-image {
    flex: 0 0 280px;
}

.hero-image img {
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

/* --- Section Titles --- */
.section-title {
    font-size: 2rem;
    font-weight: 700;
    text-align: center;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
}

.section-subtitle {
    text-align: center;
    color: var(--color-slate);
    font-size: 1.05rem;
    margin-bottom: 48px;
    max-width: 550px;
    margin-left: auto;
    margin-right: auto;
}

/* --- Features --- */
.features {
    padding: 80px 0;
}

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

.feature-card {
    background: var(--color-white);
    border-radius: var(--radius);
    padding: 32px 28px;
    border: 1px solid var(--color-border);
    transition: all var(--transition);
}

.feature-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-amber);
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: 16px;
}

.feature-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.feature-card p {
    font-size: 0.92rem;
    color: var(--color-slate);
    line-height: 1.6;
}

/* --- How It Works --- */
.how-it-works {
    padding: 80px 0;
    background: var(--color-white);
}

.steps {
    display: flex;
    align-items: flex-start;
    justify-content: center;
    gap: 24px;
}

.step {
    text-align: center;
    max-width: 260px;
}

.step-number {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--color-amber);
    color: var(--color-charcoal);
    font-size: 1.25rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
}

.step h3 {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.step p {
    font-size: 0.92rem;
    color: var(--color-slate);
    line-height: 1.6;
}

.step-arrow {
    font-size: 1.5rem;
    color: var(--color-slate-light);
    margin-top: 12px;
    flex-shrink: 0;
}

/* --- Screenshots --- */
.screenshots {
    padding: 80px 0;
}

.screenshots-scroll {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scroll-snap-type: x mandatory;
    padding: 0 20px 20px;
    scrollbar-width: thin;
    scrollbar-color: var(--color-border) transparent;
}

.screenshots-scroll::-webkit-scrollbar {
    height: 6px;
}

.screenshots-scroll::-webkit-scrollbar-track {
    background: transparent;
}

.screenshots-scroll::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: 3px;
}

.screenshots-track {
    display: flex;
    gap: 24px;
    width: max-content;
    padding: 0 calc((100vw - var(--max-width)) / 2);
}

.screenshot-item {
    scroll-snap-align: center;
    flex-shrink: 0;
    width: 220px;
    text-align: center;
}

.screenshot-item img {
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    width: 100%;
    transition: transform var(--transition);
}

.screenshot-item img:hover {
    transform: scale(1.02);
}

.screenshot-caption {
    margin-top: 12px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--color-slate);
}

/* --- Feedback --- */
.feedback {
    padding: 80px 0;
    background: var(--color-white);
}

.feedback-form {
    max-width: 560px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 24px;
}

.form-group label {
    display: block;
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.form-group textarea,
.form-group input[type="text"] {
    width: 100%;
    padding: 14px 16px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    font-size: 1rem;
    font-family: inherit;
    background: var(--color-bg);
    color: var(--color-charcoal);
    transition: border-color var(--transition);
    resize: vertical;
}

.form-group textarea:focus,
.form-group input[type="text"]:focus {
    outline: none;
    border-color: var(--color-amber);
    box-shadow: 0 0 0 3px var(--color-amber-light);
}

.form-hint {
    display: block;
    font-size: 0.8rem;
    color: var(--color-slate-light);
    margin-top: 6px;
}

.captcha-group input[type="text"] {
    max-width: 160px;
}

/* Honeypot — hidden from real users */
.hp-field {
    position: absolute;
    left: -9999px;
    opacity: 0;
    height: 0;
    overflow: hidden;
}

.alert {
    padding: 16px 20px;
    border-radius: var(--radius);
    font-size: 0.95rem;
    margin-bottom: 24px;
}

.alert-success {
    background: #ECFDF5;
    color: #065F46;
    border: 1px solid #A7F3D0;
}

.alert-error {
    background: #FEF2F2;
    color: #991B1B;
    border: 1px solid #FECACA;
}

/* --- Privacy --- */
.privacy {
    padding: 80px 0 60px;
}

.privacy h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.privacy-updated {
    color: var(--color-slate);
    margin-bottom: 40px;
}

.privacy h2 {
    font-size: 1.3rem;
    font-weight: 600;
    margin-top: 32px;
    margin-bottom: 12px;
}

.privacy p {
    color: var(--color-slate);
    margin-bottom: 12px;
    max-width: 700px;
}

.privacy ul {
    padding-left: 24px;
    margin-bottom: 12px;
}

.privacy li {
    color: var(--color-slate);
    margin-bottom: 8px;
    line-height: 1.6;
}

.privacy a {
    color: var(--color-amber-dark);
    font-weight: 500;
}

/* --- Footer --- */
.footer {
    background: var(--color-charcoal);
    color: var(--color-white);
    padding-top: 60px;
}

.footer-inner {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.footer-brand .logo {
    color: var(--color-white);
    display: block;
    margin-bottom: 8px;
}

.footer-brand p {
    color: var(--color-slate-light);
    font-size: 0.9rem;
}

.footer h4 {
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 16px;
    color: var(--color-slate-light);
}

.footer-links a,
.footer-contact a {
    display: block;
    color: var(--color-white);
    font-size: 0.9rem;
    margin-bottom: 10px;
    opacity: 0.85;
}

.footer-links a:hover,
.footer-contact a:hover {
    opacity: 1;
    color: var(--color-amber);
}

.footer-bottom {
    padding: 20px 0;
    text-align: center;
}

.footer-bottom p {
    font-size: 0.8rem;
    color: var(--color-slate-light);
}

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

/* Tablet */
@media (max-width: 900px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .footer-brand {
        grid-column: 1 / -1;
    }

    .hero-text h1 {
        font-size: 2.4rem;
    }

    .hero-inner {
        gap: 40px;
    }

    .hero-image {
        flex: 0 0 220px;
    }
}

/* Mobile */
@media (max-width: 640px) {
    .nav {
        display: none;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: var(--color-white);
        flex-direction: column;
        gap: 0;
        border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow-lg);
    }

    .nav-open {
        display: flex;
    }

    .nav a {
        padding: 16px 20px;
        border-bottom: 1px solid var(--color-border);
        font-size: 1rem;
    }

    .nav-toggle {
        display: flex;
    }

    .hero {
        padding: 40px 0;
    }

    .hero-inner {
        flex-direction: column-reverse;
        text-align: center;
        gap: 32px;
    }

    .hero-text h1 {
        font-size: 2rem;
    }

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

    .hero-actions {
        justify-content: center;
    }

    .hero-image {
        flex: none;
        width: 200px;
        margin: 0 auto;
    }

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

    .steps {
        flex-direction: column;
        align-items: center;
    }

    .step-arrow {
        transform: rotate(90deg);
        margin: 0;
    }

    .section-title {
        font-size: 1.6rem;
    }

    .screenshot-item {
        width: 180px;
    }

    .screenshots-track {
        padding: 0 20px;
    }

    .footer-inner {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .privacy h1 {
        font-size: 1.8rem;
    }

    .btn {
        padding: 12px 24px;
        font-size: 0.9rem;
    }
}

/* Extra small (iPhone SE, etc.) */
@media (max-width: 375px) {
    .hero-text h1 {
        font-size: 1.7rem;
    }

    .hero-image {
        width: 160px;
    }

    .screenshot-item {
        width: 150px;
    }
}