:root {
    --bg: #f4f7fb;
    --bg-secondary: #e9eef7;
    --surface: rgba(255, 255, 255, 0.88);
    --surface-strong: rgba(255, 255, 255, 0.96);
    --text: #14213d;
    --muted: #5b6b88;
    --border: rgba(20, 33, 61, 0.12);
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --shadow: 0 16px 40px rgba(20, 33, 61, 0.12);
    --input-bg: #ffffff;
    --alert-bg: #eef4ff;
    --alert-text: #1d4ed8;
}

body.dark {
    --bg: #081224;
    --bg-secondary: #0d1b34;
    --surface: rgba(15, 28, 56, 0.82);
    --surface-strong: rgba(12, 24, 48, 0.94);
    --text: #f3f7ff;
    --muted: #b8c5de;
    --border: rgba(255, 255, 255, 0.10);
    --primary: #60a5fa;
    --primary-hover: #3b82f6;
    --shadow: 0 18px 42px rgba(0, 0, 0, 0.30);
    --input-bg: rgba(3, 10, 25, 0.85);
    --alert-bg: rgba(37, 99, 235, 0.14);
    --alert-text: #cfe2ff;
}

* {
    box-sizing: border-box;
}

html {
    font-size: 16px;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    color: var(--text);
    background:
        radial-gradient(circle at top left, var(--bg-secondary), transparent 35%),
        linear-gradient(160deg, var(--bg), var(--bg-secondary));
    min-height: 100vh;
    transition: background 0.25s ease, color 0.25s ease;
}

.page-shell {
    width: min(1120px, calc(100% - 2rem));
    margin: 0 auto;
    padding: 1.25rem 0 2rem;
}

.hero {
    padding: 1rem 0 1.5rem;
}

.hero__content {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1rem;
}

.eyebrow {
    margin: 0 0 0.4rem;
    color: var(--primary);
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    font-size: 0.85rem;
}

h1 {
    margin: 0;
    font-size: clamp(2.2rem, 5vw, 4.2rem);
    line-height: 1.05;
}

.hero__text {
    max-width: 700px;
    margin-top: 0.9rem;
    color: var(--muted);
    font-size: 1rem;
    line-height: 1.6;
}

.theme-toggle {
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    padding: 0.8rem 1rem;
    border-radius: 999px;
    cursor: pointer;
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, background 0.2s ease;
    backdrop-filter: blur(10px);
}

.theme-toggle:hover {
    transform: translateY(-1px);
}

.content-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1.25rem;
}

.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 22px;
    padding: 1.4rem;
    box-shadow: var(--shadow);
    backdrop-filter: blur(14px);
}

.card h2 {
    margin-top: 0;
    margin-bottom: 1rem;
    font-size: 1.6rem;
}

.form {
    display: grid;
    gap: 0.9rem;
}

.form-group {
    display: grid;
    gap: 0.45rem;
}

label {
    font-weight: 600;
    color: var(--text);
}

input {
    width: 100%;
    border: 1px solid var(--border);
    background: var(--input-bg);
    color: var(--text);
    border-radius: 14px;
    padding: 0.95rem 1rem;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.18);
}

.btn {
    border: none;
    border-radius: 14px;
    padding: 0.95rem 1.1rem;
    font-size: 1rem;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.15s ease, background 0.2s ease;
}

.btn:hover {
    transform: translateY(-1px);
}

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

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

.alert {
    margin-bottom: 1rem;
    padding: 0.9rem 1rem;
    border-radius: 14px;
    background: var(--alert-bg);
    color: var(--alert-text);
    border: 1px solid var(--border);
}

@media (max-width: 900px) {
    .content-grid {
        grid-template-columns: 1fr;
    }

    .hero__content {
        flex-direction: column;
        align-items: stretch;
    }

    .theme-toggle {
        align-self: flex-start;
    }
}

@media (max-width: 600px) {
    .page-shell {
        width: min(100% - 1rem, 100%);
        padding-top: 0.75rem;
    }

    .card {
        padding: 1rem;
        border-radius: 18px;
    }

    h1 {
        font-size: 2.4rem;
    }

    .card h2 {
        font-size: 1.35rem;
    }

    input,
    .btn {
        font-size: 1rem;
    }
}