:root {
    --green: #16834f;
    --red: #c0392b;
    --light: #f7f7f5;
    --dark: #222;
    --muted: #666;
    --border: #e6e6e6;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: var(--light);
    color: var(--dark);
}

.container {
    width: min(1100px, 92%);
    margin: 0 auto;
}

.topbar {
    background: #fff;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 10;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 0;
    gap: 20px;
}

.logo {
    font-weight: 700;
    font-size: 20px;
    color: var(--green);
    text-decoration: none;
}

nav a {
    margin-left: 14px;
    color: var(--dark);
    text-decoration: none;
    font-weight: 600;
}

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

.hero {
    background: linear-gradient(135deg, #ffffff, #f1fff7);
    border: 1px solid var(--border);
    padding: 40px;
    border-radius: 18px;
    margin: 30px 0;
}

.hero h1 {
    margin-top: 0;
    font-size: 38px;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
    gap: 18px;
}

.card {
    background: #fff;
    border: 1px solid var(--border);
    padding: 22px;
    border-radius: 16px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.04);
}

.card h3 { margin-top: 0; }

.btn {
    display: inline-block;
    border: 0;
    padding: 11px 16px;
    border-radius: 10px;
    background: var(--green);
    color: #fff;
    text-decoration: none;
    cursor: pointer;
    font-weight: 700;
}

.btn.red { background: var(--red); }
.btn.gray { background: #555; }
.btn.small { padding: 7px 10px; font-size: 13px; }

input, select, textarea {
    width: 100%;
    padding: 12px;
    margin: 8px 0 14px;
    border: 1px solid var(--border);
    border-radius: 10px;
    font-size: 15px;
}

label { font-weight: 700; }

.alert {
    padding: 12px;
    border-radius: 10px;
    margin-bottom: 15px;
}

.alert.error {
    background: #ffecec;
    border: 1px solid #ffbbbb;
}

.alert.success {
    background: #edfff4;
    border: 1px solid #b8eacb;
}

.word {
    display: flex;
    justify-content: space-between;
    gap: 18px;
    align-items: flex-start;
    margin-bottom: 16px;
}

.word-title {
    font-size: 24px;
    color: var(--green);
    font-weight: 800;
    cursor: pointer;
}

.progress {
    background: #eee;
    border-radius: 99px;
    height: 12px;
    overflow: hidden;
}

.progress > div {
    background: var(--green);
    height: 12px;
}

.table {
    width: 100%;
    border-collapse: collapse;
    background: #fff;
}

.table th, .table td {
    padding: 12px;
    border-bottom: 1px solid var(--border);
    text-align: left;
}

.flashcard {
    min-height: 220px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 34px;
    text-align: center;
    cursor: pointer;
}

.footer {
    margin-top: 60px;
    padding: 24px 0;
    background: #fff;
    border-top: 1px solid var(--border);
    color: var(--muted);
}

@media (max-width: 700px) {
    .nav { flex-direction: column; align-items: flex-start; }
    nav a { margin-left: 0; margin-right: 10px; display: inline-block; margin-top: 8px; }
    .hero h1 { font-size: 30px; }
    .word { flex-direction: column; }
}

pre{background:#f3f3f3;padding:14px;border-radius:10px;overflow-x:auto;}
input[type="checkbox"],input[type="radio"]{width:auto;margin-right:8px;}