* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
    min-height: 100%;
    font-family: Arial, sans-serif;
    background: #f3f4f6;
    color: #111827;
}

body {
    min-height: 100vh;
}

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

.app-header {
    background: #111111;
    color: white;
    padding: 18px 20px;
    text-align: center;
}

.logo {
    font-size: 18px;
    font-weight: 700;
    letter-spacing: 1px;
}

.app-main {
    width: 100%;
    max-width: 520px;
    margin: 0 auto;
    padding: 24px 16px;
    flex: 1;
}

.screen {
    display: none;
}

.screen.active {
    display: block;
}

.card {
    background: white;
    border-radius: 18px;
    padding: 24px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

h1 {
    margin: 0 0 8px;
    font-size: 28px;
}

.subtitle {
    margin: 0 0 24px;
    color: #6b7280;
}

label {
    display: block;
    margin-bottom: 16px;
    font-weight: 600;
    font-size: 14px;
}

input {
    width: 100%;
    margin-top: 7px;
    padding: 13px 14px;
    border: 1px solid #d1d5db;
    border-radius: 10px;
    font-size: 16px;
    outline: none;
}

input:focus {
    border-color: #111111;
}

.button {
    width: 100%;
    border: 0;
    border-radius: 10px;
    padding: 14px;
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
}

.primary {
    background: #111111;
    color: white;
}

.secondary {
    margin-top: 20px;
    background: #e5e7eb;
    color: #111827;
}

.switch-auth {
    margin-top: 22px;
    text-align: center;
    color: #6b7280;
    font-size: 14px;
}

.link-button {
    border: 0;
    background: none;
    padding: 0;
    color: #111111;
    font-weight: 700;
    cursor: pointer;
}

.error {
    display: none;
    margin-bottom: 15px;
    padding: 10px;
    border-radius: 8px;
    background: #fee2e2;
    color: #991b1b;
    font-size: 14px;
}

.error.show {
    display: block;
}

.home-menu {
    display: grid;
    gap: 10px;
    margin-top: 20px;
}

.menu-button {
    width: 100%;
    padding: 16px;
    border: 1px solid #e5e7eb;
    border-radius: 12px;
    background: white;
    text-align: left;
    font-size: 16px;
    cursor: pointer;
}

.menu-button:hover {
    background: #f9fafb;
}

.loader {
    width: 38px;
    height: 38px;
    margin: 80px auto 15px;
    border: 4px solid #e5e7eb;
    border-top-color: #111111;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

.loading-text {
    text-align: center;
    color: #6b7280;
}

.app-footer {
    padding: 18px;
    text-align: center;
    color: #9ca3af;
    font-size: 12px;
}

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