@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700&display=swap');

:root {
    --bg-gradient: linear-gradient(to right, #6a11cb, #2575fc);
    --text-color: #fff;
    --surface: rgba(255,255,255,0.12);
    --surface-border: #ffffff44;
    --button-primary: #ffeb3b;
    --button-primary-text: #333;
    --button-ghost-border: #ffffff66;
    --button-ghost-text: #fff;
    --shadow: 0 4px 6px rgba(0,0,0,0.1);
}

body[data-theme="light"] {
    --bg-gradient: linear-gradient(to right, #f8fbff, #dfe9f3);
    --text-color: #1f2a37;
    --surface: rgba(255,255,255,0.85);
    --surface-border: #d0d7de;
    --button-primary: #2563eb;
    --button-primary-text: #fff;
    --button-ghost-border: #94a3b8;
    --button-ghost-text: #1f2a37;
    --shadow: 0 6px 12px rgba(15,23,42,0.12);
}

body {
    font-family: 'Poppins', sans-serif;
    text-align: center;
    background: var(--bg-gradient);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    transition: background 0.3s ease, color 0.3s ease;
}

header {
    padding: 2rem 0;
}

header .header-inner {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

h1 {
    font-size: 3rem;
    font-weight: 700;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

main {
    padding: 1em;
}

h2 {
    margin-top: 2.5rem;
}

.number-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 0.5em;
    margin: 2em auto;
    max-width: 420px;
}

.number-grid > div {
    border: 1px solid var(--surface-border);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    user-select: none;
    transition: all 0.3s ease;
    background: var(--surface);
    box-shadow: var(--shadow);
}

.number-grid > div:hover {
    background: var(--surface);
    transform: translateY(-3px);
}

#recommend-button {
    background: var(--button-primary);
    color: var(--button-primary-text);
    padding: 1em 2em;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    font-size: 1.2em;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

#recommend-button:hover {
    background: var(--button-primary);
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.helper-text {
    font-size: 1.2rem;
}

ul#history-list {
    list-style: none;
    padding: 0;
    margin: 1em auto 2em;
    max-width: 420px;
}

ul#history-list li {
    background: var(--surface);
    border: 1px solid var(--surface-border);
    border-radius: 12px;
    padding: 0.6em 1em;
    margin-bottom: 0.6em;
    box-shadow: var(--shadow);
}

#reset-button {
    background: transparent;
    color: var(--button-ghost-text);
    padding: 1em 2em;
    border: 1px solid var(--button-ghost-border);
    border-radius: 50px;
    cursor: pointer;
    font-size: 1.1em;
    font-weight: 500;
    margin-left: 0.5em;
    transition: all 0.3s ease;
}

#reset-button:hover {
    background: var(--surface);
    transform: translateY(-3px);
}

.theme-toggle {
    background: transparent;
    color: var(--button-ghost-text);
    border: 1px solid var(--button-ghost-border);
    border-radius: 999px;
    padding: 0.5em 1em;
    cursor: pointer;
    font-size: 0.95rem;
    transition: all 0.3s ease;
}

.theme-toggle:hover {
    background: var(--surface);
    transform: translateY(-2px);
}

#partnership {
    margin: 2.5rem auto 1.5rem;
    max-width: 520px;
}

#partnership-form {
    display: flex;
    flex-direction: column;
    gap: 0.9rem;
    margin-top: 1.2rem;
    text-align: left;
}

#partnership-form label {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    font-weight: 500;
}

#partnership-form input,
#partnership-form textarea {
    font-family: 'Poppins', sans-serif;
    padding: 0.8rem 1rem;
    border-radius: 12px;
    border: 1px solid var(--surface-border);
    background: var(--surface);
    color: var(--text-color);
    box-shadow: var(--shadow);
}

#partnership-form input::placeholder,
#partnership-form textarea::placeholder {
    color: rgba(255,255,255,0.7);
}

body[data-theme="light"] #partnership-form input::placeholder,
body[data-theme="light"] #partnership-form textarea::placeholder {
    color: rgba(31,42,55,0.6);
}

.form-submit {
    align-self: center;
    background: var(--button-primary);
    color: var(--button-primary-text);
    border: none;
    border-radius: 999px;
    padding: 0.9rem 2.2rem;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

.form-submit:hover {
    transform: translateY(-3px);
}