:root {
    --bg-color: #ffffff;
    --container-bg: #ffffff;
    --text-color: #000000;
    --desc-color: #333333;
    --placeholder-color: #666666;
    --button-bg: #000000;
    --button-hover: #333333;
    --shadow: none;
    --input-bg: #ffffff;
    --input-border: #000000;
    --accent-color: #000000;
    --border-width: 2px;
}

[data-theme="dark"] {
    --bg-color: #121212;
    --container-bg: #121212;
    --text-color: #ffffff;
    --desc-color: #cccccc;
    --placeholder-color: #888888;
    --button-bg: #ffffff;
    --button-hover: #dddddd;
    --shadow: none;
    --input-bg: #1e1e1e;
    --input-border: #ffffff;
    --accent-color: #ffffff;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
    padding: 2rem 0;
    line-height: 1.5;
    transition: background-color 0.2s, color 0.2s;
}

.container {
    background-color: var(--container-bg);
    padding: 2.5rem;
    border: var(--border-width) solid var(--input-border);
    text-align: center;
    width: 95%;
    max-width: 1200px;
    position: relative;
    transition: background-color 0.3s, box-shadow 0.3s;
}

.theme-toggle {
    position: absolute;
    top: 1rem;
    right: 1rem;
}

#theme-btn {
    background: none;
    border: 1px solid var(--input-border);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 5px 10px;
}

#theme-btn:hover {
    background-color: var(--input-border);
    color: var(--container-bg);
}

header {
    margin-bottom: 2rem;
    text-align: left;
}

h1 {
    font-size: 2.5rem;
    font-weight: 900;
    text-transform: uppercase;
    border-left: 10px solid var(--accent-color);
    padding-left: 1rem;
    margin-bottom: 0.5rem;
}

.section-desc {
    color: var(--desc-color);
    font-weight: 600;
    border-bottom: var(--border-width) solid var(--input-border);
    padding-bottom: 1rem;
}

/* 탭 메뉴 스타일 */
.tab-menu {
    display: flex;
    justify-content: flex-start;
    gap: 0;
    margin-bottom: 2rem;
    border-bottom: var(--border-width) solid var(--input-border);
    flex-wrap: wrap;
}

.tab-btn {
    padding: 0.8rem 1.2rem;
    border: var(--border-width) solid transparent;
    border-bottom: none;
    background: none;
    cursor: pointer;
    font-weight: bold;
    color: var(--placeholder-color);
    text-transform: uppercase;
    letter-spacing: 1px;
    font-size: 0.85rem;
}

.tab-btn.active {
    border-color: var(--input-border);
    background-color: var(--container-bg);
    color: var(--text-color);
    margin-bottom: -var(--border-width);
}

/* 섹션 가시성 및 레이아웃 */
.content-section {
    display: none;
    text-align: left;
    animation: fadeIn 0.3s ease;
}

.content-section.active {
    display: block;
}

/* 리사이저 섹션 2열 레이아웃 */
#resizer-section.active {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 2.5rem;
    align-items: start;
}

.resizer-main {
    grid-column: 1;
}

.resizer-side {
    grid-column: 2;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* 컨트롤 그리드 */
.controls-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.2rem;
    text-align: left;
    border: 1px solid var(--input-border);
    padding: 1.5rem;
}

.control-group label {
    display: block;
    font-weight: 800;
    text-transform: uppercase;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

select, input[type="text"] {
    width: 100%;
    padding: 0.8rem;
    border: var(--border-width) solid var(--input-border);
    background-color: var(--input-bg);
    color: var(--text-color);
    font-weight: bold;
    font-family: inherit;
    outline: none;
}

.radio-group {
    display: flex;
    gap: 0;
}

.shape-btn {
    flex: 1;
    padding: 0.8rem;
    border: var(--border-width) solid var(--input-border);
    background: none;
    color: var(--text-color);
    font-weight: 800;
    cursor: pointer;
}

.shape-btn.active {
    background-color: var(--input-border);
    color: var(--container-bg);
}

/* 에디터 영역 */
.editor-container {
    margin-bottom: 0;
}

.upload-box {
    border: var(--border-width) dashed var(--input-border);
    padding: 10rem 1rem;
    cursor: pointer;
    font-weight: 900;
    text-transform: uppercase;
    transition: background-color 0.2s;
    text-align: center;
}

.upload-box:hover {
    background-color: rgba(128, 128, 128, 0.1);
}

.canvas-wrapper {
    position: relative;
    border: var(--border-width) solid var(--input-border);
    margin: 0 auto 1.5rem;
    background-color: #eee;
    overflow: hidden;
    cursor: move;
    width: 100%;
    max-width: 100%;
    aspect-ratio: 1 / 1;
}

#main-canvas {
    display: block;
    width: 100%;
    height: 100%;
}

.mask {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    pointer-events: none;
    box-shadow: 0 0 0 9999px rgba(0, 0, 0, 0.5);
}

#circular-mask {
    border-radius: 50%;
}

/* 조절 도구 */
.adjustment-tools {
    margin-bottom: 1.5rem;
}

.slider-group {
    margin-bottom: 1rem;
}

.slider-group label {
    display: block;
    font-weight: 800;
    font-size: 0.8rem;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
}

input[type="range"] {
    width: 100%;
    accent-color: var(--accent-color);
}

.tool-hint {
    font-size: 0.8rem;
    font-weight: bold;
    color: var(--placeholder-color);
    text-transform: uppercase;
}

/* 버튼 */
button#download-btn {
    width: 100%;
    padding: 1.2rem;
    background-color: var(--button-bg);
    color: var(--container-bg);
    border: var(--border-width) solid var(--input-border);
    font-weight: 900;
    font-size: 1.1rem;
    text-transform: uppercase;
    cursor: pointer;
    margin-bottom: 1rem;
}

.secondary-btn {
    width: 100%;
    padding: 0.8rem;
    background: none;
    border: var(--border-width) solid var(--input-border);
    color: var(--text-color);
    font-weight: 800;
    text-transform: uppercase;
    cursor: pointer;
}

/* 안내 컨텐츠 */
.info-content {
    text-align: left;
    padding: 1.5rem;
    border: 1px solid var(--input-border);
}

.info-content h3 {
    font-weight: 900;
    text-transform: uppercase;
    margin-bottom: 1rem;
    border-bottom: 1px solid var(--input-border);
    display: inline-block;
}

.info-content ul {
    list-style: none;
}

.info-content li {
    margin-bottom: 0.8rem;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--desc-color);
    position: relative;
    padding-left: 1.2rem;
}

.info-content li::before {
    content: ">";
    position: absolute;
    left: 0;
    color: var(--accent-color);
}

/* 교육용 컨텐츠 스타일 */
.educational-content {
    text-align: left;
    margin-top: 2rem;
}

.educational-content h3 {
    font-weight: 900;
    text-transform: uppercase;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: var(--border-width) solid var(--input-border);
}

.tip-card {
    border: 1px solid var(--input-border);
    padding: 1.2rem;
    margin-bottom: 1rem;
}

.tip-card h4 {
    font-weight: 800;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.tip-card p {
    font-size: 0.9rem;
    color: var(--desc-color);
}

/* 제휴 문의 */
.contact-section-inner {
    max-width: 600px;
}

/* 푸터 */
footer {
    margin-top: 5rem;
    padding-top: 2rem;
    border-top: var(--border-width) solid var(--input-border);
}

.footer-links a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 900;
    text-transform: uppercase;
    font-size: 0.8rem;
    margin: 0 10px;
}

/* 모달 */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0; top: 0; width: 100%; height: 100%;
    background-color: rgba(0,0,0,0.8);
}

.modal-content {
    background-color: var(--container-bg);
    margin: 10% auto;
    padding: 2rem;
    border: var(--border-width) solid var(--input-border);
    max-width: 600px;
    position: relative;
    text-align: left;
}

.close {
    position: absolute;
    right: 1.5rem;
    top: 1rem;
    font-size: 2rem;
    font-weight: bold;
    cursor: pointer;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 900px) {
    #resizer-section.active {
        grid-template-columns: 1fr;
    }
    .resizer-main, .resizer-side {
        grid-column: 1;
    }
}