:root {
    color-scheme: dark;

    --bg-0: #0f172a;
    --bg-1: #1e293b;
    --bg-card: rgba(15, 23, 42, 0.7);
    --border: rgba(148, 163, 184, 0.2);
    --text: #e2e8f0;
    --text-muted: #94a3b8;
    --accent: #1d4ed8;
    --accent-hover: #1e40af;
    --danger: #dc2626;
    --success: #16a34a;
    --radius: 0.75rem;
    --shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
}

* { box-sizing: border-box; }

html, body {
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: linear-gradient(135deg, var(--bg-0) 0%, var(--bg-1) 100%);
    color: var(--text);
    min-height: 100vh;
    line-height: 1.5;
}

a {
    color: #60a5fa;
    text-decoration: none;
}
a:hover { text-decoration: underline; }

/* ===== Layouts ===== */

.guest-wrapper {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 1.5rem;
}

.guest-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2.5rem 2rem;
    width: 100%;
    max-width: 26rem;
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow);
}

.guest-card h1 {
    font-size: 1.5rem;
    margin: 0 0 0.25rem;
    text-align: center;
}

.guest-card .subtitle {
    color: var(--text-muted);
    text-align: center;
    font-size: 0.875rem;
    margin: 0 0 2rem;
}

/* App layout */

.app-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.app-nav {
    background: rgba(15, 23, 42, 0.85);
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(10px);
    padding: 0.875rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}

.app-nav .brand {
    font-weight: 600;
    color: var(--text);
}

.app-nav .nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.app-nav .nav-links a,
.app-nav .nav-links button {
    color: var(--text-muted);
    background: none;
    border: none;
    font: inherit;
    cursor: pointer;
    padding: 0.25rem 0;
}

.app-nav .nav-links a:hover,
.app-nav .nav-links button:hover {
    color: var(--text);
    text-decoration: none;
}

.app-nav .nav-links .active {
    color: var(--text);
}

.app-nav .user-meta {
    color: var(--text-muted);
    font-size: 0.875rem;
}

.app-main {
    flex: 1;
    padding: 2rem 1.5rem;
    max-width: 64rem;
    width: 100%;
    margin: 0 auto;
}

.app-main h1 {
    margin: 0 0 0.5rem;
    font-size: 1.5rem;
}

.app-main h2 {
    margin: 2rem 0 1rem;
    font-size: 1.125rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    backdrop-filter: blur(10px);
    margin-bottom: 1.5rem;
}

/* ===== Forms ===== */

.form-group { margin-bottom: 1.25rem; }

.form-label {
    display: block;
    margin-bottom: 0.375rem;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.form-input {
    width: 100%;
    padding: 0.625rem 0.875rem;
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--border);
    border-radius: 0.5rem;
    color: var(--text);
    font: inherit;
    transition: border-color 0.15s, box-shadow 0.15s;
}

.form-input:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(29, 78, 216, 0.25);
}

.form-checkbox {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1.25rem;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.form-checkbox input {
    width: 1rem;
    height: 1rem;
    accent-color: var(--accent);
}

.form-error {
    color: #f87171;
    font-size: 0.8125rem;
    margin-top: 0.375rem;
}

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

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.625rem 1.25rem;
    background: var(--accent);
    color: white;
    border: none;
    border-radius: 0.5rem;
    font: inherit;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: background-color 0.15s;
}

.btn:hover { background: var(--accent-hover); text-decoration: none; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-secondary {
    background: rgba(148, 163, 184, 0.15);
    color: var(--text);
}
.btn-secondary:hover { background: rgba(148, 163, 184, 0.25); }

.btn-danger { background: var(--danger); }
.btn-danger:hover { background: #b91c1c; }

.btn-block { width: 100%; }

/* ===== Alerts ===== */

.alert {
    padding: 0.75rem 1rem;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    border: 1px solid transparent;
}

.alert-success {
    background: rgba(22, 163, 74, 0.15);
    border-color: rgba(22, 163, 74, 0.3);
    color: #86efac;
}

.alert-error {
    background: rgba(220, 38, 38, 0.15);
    border-color: rgba(220, 38, 38, 0.3);
    color: #fca5a5;
}

/* ===== Welcome page ===== */

.welcome-wrapper {
    min-height: 100vh;
    display: grid;
    place-items: center;
    padding: 1.5rem;
}

.welcome-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 3rem 2.5rem;
    max-width: 32rem;
    text-align: center;
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow);
}

.welcome-card h1 { margin: 0 0 0.5rem; font-size: 1.75rem; }
.welcome-card p { margin: 0; color: var(--text-muted); }

.welcome-card .badge {
    display: inline-block;
    margin-top: 1.5rem;
    padding: 0.25rem 0.75rem;
    background: var(--accent);
    color: white;
    border-radius: 999px;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.welcome-actions {
    margin-top: 2rem;
    display: flex;
    gap: 0.75rem;
    justify-content: center;
}

/* ===== Utilities ===== */

.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.text-small { font-size: 0.875rem; }

.form-helper {
    color: var(--text-muted);
    font-size: 0.8125rem;
    margin-top: 0.375rem;
}