:root {
    --primary-color: #006655;
    --primary-hover: #005544;
    --bg-color: #ffffff;
    --text-color: #333333;
    --card-bg: #f5f5f5;
    --border-color: #dddddd;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --primary-color: #008866;
    --primary-hover: #009977;
    --bg-color: #1a1a1a;
    --text-color: #e0e0e0;
    --card-bg: #2a2a2a;
    --border-color: #444444;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid var(--primary-color);
}

h1 {
    color: var(--primary-color);
    font-size: 2rem;
}

h2 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 1.5rem;
}

h3 {
    color: var(--text-color);
    margin: 15px 0 10px;
    font-size: 1.2rem;
}

.theme-toggle {
    background: var(--primary-color);
    border: none;
    color: white;
    font-size: 1.5rem;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    transition: background-color 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

main {
    flex: 1;
}

.section {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 30px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.hidden {
    display: none !important;
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-color);
}

input[type="number"],
input[type="text"] {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 16px;
    background: var(--bg-color);
    color: var(--text-color);
    transition: border-color 0.3s ease;
}

input[type="number"]:focus,
input[type="text"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

.radio-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.radio-label {
    display: flex;
    align-items: center;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--bg-color);
}

.radio-label:hover {
    border-color: var(--primary-color);
}

.radio-label input[type="radio"] {
    margin-right: 10px;
    cursor: pointer;
}

.radio-label input[type="radio"]:checked + span {
    color: var(--primary-color);
    font-weight: 600;
}

.radio-label:has(input:checked) {
    border-color: var(--primary-color);
    background: var(--card-bg);
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: inline-block;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--text-color);
    border: 2px solid var(--primary-color);
}

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

.btn-outline {
    background: transparent;
    color: var(--text-color);
    border: 2px solid var(--border-color);
}

.btn-outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.button-group {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-top: 20px;
}

.suggestion-box {
    background: var(--bg-color);
    border: 2px solid var(--primary-color);
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 20px;
}

.info-item {
    margin: 10px 0;
    padding: 10px;
    background: var(--card-bg);
    border-radius: 6px;
}

.info-item strong {
    color: var(--primary-color);
}

.bracket {
    margin-top: 20px;
    overflow-x: auto;
}

.bracket-round {
    margin-bottom: 30px;
}

.bracket-round h3 {
    margin-bottom: 15px;
    color: var(--primary-color);
}

.bracket-matches {
    display: grid;
    gap: 10px;
}

.match {
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    padding: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.match.bye {
    border-style: dashed;
    opacity: 0.7;
}

.match-player {
    flex: 1;
    padding: 8px;
}

.match-vs {
    color: var(--primary-color);
    font-weight: bold;
    padding: 0 10px;
}

.group-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.group {
    background: var(--bg-color);
    border: 2px solid var(--primary-color);
    border-radius: 8px;
    padding: 15px;
}

.group h3 {
    color: var(--primary-color);
    margin-bottom: 10px;
}

.group-members {
    list-style: none;
}

.group-members li {
    padding: 8px;
    margin: 5px 0;
    background: var(--card-bg);
    border-radius: 4px;
}

.customize-input {
    margin-bottom: 15px;
}

.customize-input label {
    display: block;
    margin-bottom: 5px;
}

.customize-input input {
    width: 100%;
    max-width: 200px;
}

footer {
    text-align: center;
    padding: 20px;
    margin-top: 30px;
    border-top: 1px solid var(--border-color);
    color: var(--text-color);
    opacity: 0.7;
}

@media (max-width: 768px) {
    .container {
        padding: 15px;
    }

    h1 {
        font-size: 1.5rem;
    }

    h2 {
        font-size: 1.3rem;
    }

    .section {
        padding: 20px;
    }

    .button-group {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    .group-container {
        grid-template-columns: 1fr;
    }
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --primary-color: #008866;
        --primary-hover: #009977;
        --bg-color: #1a1a1a;
        --text-color: #e0e0e0;
        --card-bg: #2a2a2a;
        --border-color: #444444;
        --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    }
}