/* Mobile-first base styles */
:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-text: #1f2937;
    --color-muted: #6b7280;
    --color-border: #e5e7eb;
    --color-bg: #ffffff;
    --color-error: #dc2626;
    --max-width: 960px;
    font-size: 16px;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.5;
}

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

/* Header / Nav */
.site-header {
    border-bottom: 1px solid var(--color-border);
}

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
    max-width: var(--max-width);
    margin: 0 auto;
    position: relative;
}

.brand {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-text);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
}

.brand-icon {
    width: 1.5rem;
    height: 1.5rem;
    flex-shrink: 0;
}

.nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 4px;
    background: none;
    border: none;
    padding: 0.5rem;
    cursor: pointer;
}

.nav-toggle span {
    width: 22px;
    height: 2px;
    background: var(--color-text);
}

.nav-links {
    display: none;
    position: absolute;
    top: 100%;
    right: 0;
    left: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: 0.5rem 1rem 1rem;
}

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

.nav-links a {
    padding: 0.6rem 0;
}

.nav-links .btn-link {
    font-weight: 600;
}

/* Main content */
.site-main {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1.5rem 1rem 3rem;
}

.hero {
    text-align: center;
    padding: 2rem 0;
}

.hero h1 {
    font-size: 1.75rem;
    margin-bottom: 0.75rem;
}

.hero p {
    color: var(--color-muted);
    margin-bottom: 1.5rem;
}

.hero-actions {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.features {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
    margin-top: 2rem;
}

.feature-card {
    border: 1px solid var(--color-border);
    border-radius: 0.5rem;
    padding: 1.25rem;
}

.feature-card h2 {
    font-size: 1.1rem;
    margin: 0 0 0.5rem;
}

.feature-card p {
    color: var(--color-muted);
    margin: 0;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.7rem 1.25rem;
    border-radius: 0.4rem;
    font-weight: 600;
    border: 2px solid transparent;
    cursor: pointer;
    text-align: center;
}

.btn-primary {
    background: var(--color-primary);
    color: #fff;
}

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

.btn-secondary {
    background: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.btn-block {
    display: block;
    width: 100%;
}

/* Auth forms */
.auth-form-wrapper {
    display: flex;
    justify-content: center;
    padding: 1rem 0;
}

.auth-form {
    width: 100%;
    max-width: 380px;
    display: flex;
    flex-direction: column;
}

.auth-form h1 {
    font-size: 1.4rem;
    margin-bottom: 1rem;
    text-align: center;
}

.auth-form label {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.3rem;
}

.auth-form input {
    padding: 0.65rem 0.75rem;
    margin-bottom: 1rem;
    border: 1px solid var(--color-border);
    border-radius: 0.4rem;
    font-size: 1rem;
}

.auth-form input:focus {
    outline: none;
    border-color: var(--color-primary);
}

.auth-switch {
    text-align: center;
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--color-muted);
}

.form-error {
    background: #fef2f2;
    color: var(--color-error);
    border: 1px solid #fecaca;
    border-radius: 0.4rem;
    padding: 0.6rem 0.75rem;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.form-success {
    background: #f0fdf4;
    color: #16a34a;
    border: 1px solid #bbf7d0;
    border-radius: 0.4rem;
    padding: 0.6rem 0.75rem;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.text-center {
    text-align: center;
}

.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.3rem;
}

.form-group input {
    width: 100%;
    padding: 0.65rem 0.75rem;
    border: 1px solid var(--color-border);
    border-radius: 0.4rem;
    font-size: 1rem;
}

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

.site-footer {
    text-align: center;
    color: var(--color-muted);
    font-size: 0.85rem;
    padding: 1.5rem 1rem;
}

/* Tablet and up */
@media (min-width: 640px) {
    .hero-actions {
        flex-direction: row;
        justify-content: center;
    }

    .hero-actions .btn {
        width: auto;
    }
}

/* Desktop */
@media (min-width: 900px) {
    .nav-toggle {
        display: none;
    }

    .nav-links {
        display: flex;
        position: static;
        flex-direction: row;
        border: none;
        padding: 0;
        gap: 1.5rem;
        align-items: center;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

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