:root {
            --main-width: 900px;
            --bg-color: #f0f4f2;
            --border-color: #dee2e6;
            --primary-color: #86b300; /* 미스키 라임 */
            --secondary-color: #2d6a4f; /* 진한 녹색 */
            --text-main: #2d3748;
            --text-sub: #718096;
            --card-bg: #ffffff;
        }

        /* Material Symbol 스타일 설정 */
        .material-symbols-outlined {
            font-variation-settings:
            'FILL' 0,
            'wght' 400,
            'GRAD' 0,
            'opsz' 24;
            vertical-align: middle;
        }

        body {
            font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
            background-color: var(--bg-color);
            margin: 0;
            padding: 20px;
            display: flex;
            justify-content: center;
            color: var(--text-main);
        }

        .container {
            width: 100%;
            max-width: var(--main-width);
            background: var(--card-bg);
            padding: 30px;
            border-radius: 20px;
            box-shadow: 0 8px 30px rgba(45, 106, 79, 0.08);
            box-sizing: border-box;
            position: relative;
        }

        /* 정보 버튼 스타일 */
        .info-trigger-btn {
            position: absolute;
            top: 20px;
            right: 20px;
            background: none;
            border: none;
            color: var(--secondary-color);
            cursor: pointer;
            padding: 8px;
            border-radius: 50%;
            transition: background 0.2s;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .info-trigger-btn:hover {
            background: #f1f7f4;
        }

        header {
            margin-bottom: 25px;
            text-align: center;
        }

        h1 {
            font-size: 1.6rem;
            color: var(--secondary-color);
            margin-bottom: 25px;
            font-weight: 800;
            letter-spacing: -0.5px;
        }

        .controls {
            display: flex;
            flex-direction: column;
            gap: 15px;
            margin-bottom: 30px;
        }

        .search-row {
            display: flex;
        }

        .search-box {
            flex: 1;
            padding: 14px 24px;
            border: 2px solid var(--border-color);
            border-radius: 14px;
            font-size: 16px;
            outline: none;
            transition: all 0.25s ease;
            background-color: #fafafa;
        }

        .search-box:focus {
            border-color: var(--secondary-color);
            background-color: #fff;
            box-shadow: 0 0 0 4px rgba(45, 106, 79, 0.1);
        }

        .filter-row {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 18px;
            background: #f1f7f4;
            border-radius: 16px;
            border: 1px solid var(--border-color);
        }

        .category-wrapper {
            flex: 1;
            display: flex;
            align-items: center;
            gap: 12px;
        }

        .filter-label {
            font-weight: 700;
            font-size: 0.95rem;
            color: var(--secondary-color);
            white-space: nowrap;
        }

        .category-select {
            flex: 1;
            padding: 10px 15px;
            border: 2px solid var(--border-color);
            border-radius: 10px;
            background-color: white;
            font-size: 0.95rem;
            color: var(--text-main);
            outline: none;
            cursor: pointer;
            appearance: none;
            background-image: url("data:image/svg+xml;charset=UTF-8,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%232d6a4f' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
            background-repeat: no-repeat;
            background-position: right 12px center;
            background-size: 16px;
            padding-right: 35px;
            transition: border-color 0.2s;
        }

        .category-select:hover {
            border-color: var(--secondary-color);
        }

        .sort-btn {
            padding: 10px 18px;
            border: 2px solid var(--secondary-color);
            background: white;
            color: var(--secondary-color);
            border-radius: 10px;
            cursor: pointer;
            font-weight: 700;
            font-size: 0.9rem;
            white-space: nowrap;
            transition: all 0.2s;
        }

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

        .tweet-card {
            border-bottom: 1px solid #f0f0f0;
            padding: 28px 0;
        }

        .tweet-card:last-child {
            border-bottom: none;
        }

        .tweet-header {
            display: flex;
            justify-content: space-between;
            align-items: flex-start;
            margin-bottom: 14px;
            gap: 15px;
        }

        .tweet-info {
            display: flex;
            flex-direction: column;
            gap: 6px;
        }

        .tweet-date {
            font-size: 0.85rem;
            color: var(--text-sub);
            font-weight: 600;
            letter-spacing: 0.02em;
        }

        .tweet-topic {
            font-size: 1.2rem;
            font-weight: 700;
            line-height: 1.45;
            color: #1a202c;
        }

        .tweet-content-box {
            background: #fcfcfd;
            border-radius: 14px;
            overflow: hidden;
            border: 1px solid #edf2f7;
            transition: all 0.2s;
        }

        .tweet-content-box:hover {
            border-color: var(--secondary-color);
        }

        .tweet-content-box summary {
            padding: 14px 18px 14px 40px;
            font-weight: 700;
            color: var(--secondary-color);
            cursor: pointer;
            user-select: none;
            outline: none;
            position: relative;
            list-style: none;
        }

        .tweet-content-box summary::before {
            content: '';
            position: absolute;
            left: 18px;
            top: 50%;
            transform: translateY(-50%);
            border-left: 6px solid var(--primary-color);
            border-top: 5px solid transparent;
            border-bottom: 5px solid transparent;
            transition: transform 0.2s;
        }

        .tweet-content-box[open] summary::before {
            transform: translateY(-50%) rotate(90deg);
        }

        .tweet-content-box summary::-webkit-details-marker {
            display: none;
        }

        .content {
            padding: 5px 18px 20px 40px;
            line-height: 1.8;
            color: #4a5568;
            white-space: pre-wrap;
            font-size: 0.98rem;
        }

        .link-btn {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            width: 44px;
            height: 44px;
            background-color: #f1f7f4;
            color: var(--secondary-color) !important;
            text-decoration: none;
            border-radius: 12px;
            transition: all 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
            flex-shrink: 0;
        }

        .link-btn:hover {
            background-color: var(--primary-color);
            color: white !important;
            transform: translateY(-3px) rotate(8deg);
        }

        /* 팝업 모달 스타일 */
        .modal-overlay {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.5);
            display: none; /* 초기 숨김 */
            align-items: center;
            justify-content: center;
            z-index: 1000;
            padding: 20px;
            box-sizing: border-box;
        }

        .modal-content {
            background: white;
            padding: 25px;
            border-radius: 18px;
            max-width: 450px;
            width: 100%;
            position: relative;
            box-shadow: 0 10px 25px rgba(0,0,0,0.2);
            animation: modalPop 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
        }

        @keyframes modalPop {
            from { transform: scale(0.9); opacity: 0; }
            to { transform: scale(1); opacity: 1; }
        }

        .modal-close-btn {
            position: absolute;
            top: 15px;
            right: 15px;
            background: none;
            border: none;
            color: var(--text-sub);
            cursor: pointer;
            padding: 5px;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .modal-title {
            font-weight: 800;
            color: var(--secondary-color);
            margin-bottom: 15px;
            display: flex;
            align-items: center;
            gap: 8px;
        }

        .modal-body {
            line-height: 1.6;
            color: #4a5568;
            font-size: 0.95rem;
        }

        .status-msg {
            text-align: center;
            padding: 60px 0;
            color: var(--text-sub);
            font-weight: 500;
        }

        @media (max-width: 600px) {
            .container { padding: 20px; border-radius: 0; }
            body { padding: 0; }
            .filter-row { flex-direction: column; align-items: stretch; }
            .category-wrapper { width: 100%; }
            .sort-btn { width: 100%; text-align: center; }
            .tweet-header { flex-direction: row; align-items: center; }
            .info-trigger-btn { top: 15px; right: 15px; }
        }