:root {
    /* Tells browsers the page supports both schemes so native form controls,
       scrollbars and the default `<input>` background adapt automatically.
       Pairs with the @media (prefers-color-scheme: dark) overrides below. */
    color-scheme: light dark;

    --primary-color: #099BAD;
    --primary-hover: #078a9a;
    --success-color: #307ADC;
    --error-color: #dc3545;
    --warning-color: #ffc107;
    --text-color: #333;
    --text-secondary: #666;
    --background: #f5f5f5;
    --card-background: white;
    --border-radius: 12px;
    --box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--background);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    background: var(--card-background);
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    max-width: 500px;
    width: 100%;
    text-align: center;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 10px;
}

h1, h2 {
    margin-bottom: 20px;
}

h1 {
    font-size: 28px;
    color: var(--text-color);
}

h2 {
    font-size: 24px;
}

p {
    margin-bottom: 16px;
    color: var(--text-secondary);
}

.status-success { color: var(--success-color); }
.status-error { color: var(--error-color); }
.status-warning { color: var(--warning-color); }
.status-loading { color: var(--text-secondary); }

.spinner {
    border: 3px solid #f3f3f3;
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 20px auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    margin: 10px 5px;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 16px;
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: #f8f9fa;
    color: var(--text-color);
    border: 1px solid #dee2e6;
}

.btn-secondary:hover {
    background-color: #e9ecef;
}

.small-text {
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 20px;
}

.icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.home-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    margin-top: 30px;
}

.feature-card {
    padding: 20px;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    text-align: center;
}

@media (max-width: 480px) {
    .container {
        padding: 30px 20px;
        margin: 10px;
    }

    h1 { font-size: 24px; }
    h2 { font-size: 20px; }
}

/* Dark mode — palette mirrors the email-template dark mode in
   cue-cashback-supabase/functions/send-email-hook/templates/_layout.tsx so
   the inbox view and the post-click landing page stay visually consistent
   when the user's system is in dark mode. iOS-aligned tokens: #1c1c1e
   outer, #2c2c2e card, #4DC9D9 brand teal (lighter for AA contrast on dark),
   #8e8e93 muted text. CSS-variable inheritance means most components
   adapt automatically — the explicit overrides below are for elements with
   hard-coded light-mode values (light-grey borders, white form inputs). */
@media (prefers-color-scheme: dark) {
    :root {
        --text-color: #ffffff;
        --text-secondary: #8e8e93;
        --background: #1c1c1e;
        --card-background: #2c2c2e;
        --primary-color: #4DC9D9;
        --primary-hover: #66d6e3;
        --box-shadow: 0 2px 10px rgba(0, 0, 0, 0.4);
    }

    /* Spinner base ring needs a darker shade visible on the dark card. */
    .spinner {
        border-color: #3a3a3c;
        border-top-color: var(--primary-color);
    }

    /* Secondary button — light-grey background flips to muted dark. */
    .btn-secondary {
        background-color: #3a3a3c;
        color: var(--text-color);
        border-color: #48484a;
    }

    .btn-secondary:hover {
        background-color: #48484a;
    }

    /* Feature card border (home grid). */
    .feature-card {
        border-color: #3a3a3c;
    }

    /* NOTE: Dark-mode overrides for `.form-group input` and
       `.requirements li .check` live in reset/index.html's inline <style>
       block, not here. Those selectors are defined in the inline block,
       which loads AFTER this stylesheet — same-specificity dark-mode rules
       here would lose the cascade tie. The shared palette (set on :root
       above) still applies via CSS-variable inheritance. */
}