:root {
    --bg-main: #0f172a;
    --sidebar-bg: #1e293b;
    --accent: #38bdf8;
    --accent-hover: #0ea5e9;
    --text-main: #f8fafc;
    --text-dim: #94a3b8;
    --card-bg: rgba(255, 255, 255, 0.05);
    --border: rgba(255, 255, 255, 0.1);
    --input-bg: rgba(0, 0, 0, 0.2);
    --grid-bg: #0f172a;
}

body.light-theme {
    --bg-main: #f8fafc;
    --sidebar-bg: #ffffff;
    --accent: #f97316;
    --accent-hover: #ea580c;
    --text-main: #1e293b;
    --text-dim: #64748b;
    --card-bg: #ffffff;
    --border: #e2e8f0;
    --input-bg: #f1f5f9;
    --grid-bg: #ffffff;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    overflow: hidden;
    transition: background 0.3s;
}

#app { display: flex; height: 100vh; }

/* 로딩 오버레이 */
#loading-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background: var(--bg-main); z-index: 9999;
    display: flex; justify-content: center; align-items: center; text-align: center;
    transition: opacity 0.5s;
}
#loading-overlay.hidden { opacity: 0; pointer-events: none; }
.spinner {
    width: 40px; height: 40px; border: 4px solid var(--border);
    border-top: 4px solid var(--accent); border-radius: 50%;
    animation: spin 1s linear infinite; margin: 0 auto 1.5rem;
}
@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }

/* 사이드바 */
.sidebar {
    width: 260px; background: var(--sidebar-bg);
    padding: 2rem 1.5rem; border-right: 1px solid var(--border);
    display: flex; flex-direction: column;
}
.logo { font-size: 1.5rem; font-weight: 800; color: var(--accent); margin-bottom: 2.5rem; }
.nav-item {
    padding: 0.8rem 1rem; margin-bottom: 0.4rem; border-radius: 10px;
    cursor: pointer; display: flex; align-items: center; gap: 12px;
    color: var(--text-dim); transition: 0.2s;
}
.nav-item.active { background: var(--accent); color: white; font-weight: 600; }
.nav-item:hover:not(.active) { background: rgba(var(--accent), 0.1); color: var(--text-main); }

/* 메인 콘텐츠 */
.content { flex: 1; padding: 2.5rem; overflow-y: auto; }
.tab-content { display: none; animation: fadeIn 0.3s; }
.tab-content.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: translateY(0); } }

header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 2rem; }
h1 { font-size: 1.8rem; }

/* 폼 스타일 */
.form-card {
    background: var(--card-bg); padding: 1.5rem; border-radius: 15px;
    border: 1px solid var(--border); margin-bottom: 2rem;
}
.form-row { display: grid; gap: 1rem; margin-top: 1rem; }
.time-input-row { grid-template-columns: 120px 1fr 1fr; }
.time-picker {
    display: flex; align-items: center; gap: 4px;
    background: var(--input-bg); padding: 6px 10px; border-radius: 8px; border: 1px solid var(--border);
}
.time-picker input {
    width: 45px; background: transparent; border: none; color: white; text-align: center; font-size: 0.95rem;
}
body.light-theme .time-picker input { color: #1e293b; }
.time-picker select { background: transparent; border: none; color: inherit; cursor: pointer; }

input, select {
    width: 100%; padding: 0.7rem; border-radius: 8px;
    background: var(--input-bg); border: 1px solid var(--border); color: white;
}
body.light-theme input, body.light-theme select { color: #1e293b; }

/* 버튼 */
.primary-btn { background: var(--accent); color: white; border: none; padding: 0.7rem 1.2rem; border-radius: 10px; cursor: pointer; font-weight: 600; }
.secondary-btn { background: rgba(255,255,255,0.05); color: var(--text-main); border: 1px solid var(--border); padding: 0.7rem 1.2rem; border-radius: 10px; cursor: pointer; }
body.light-theme .secondary-btn { background: #f1f5f9; }

/* 캘린더 */
.calendar-container {
    background: var(--card-bg); border-radius: 15px; border: 1px solid var(--border);
    overflow-x: auto; padding: 10px;
}
.calendar-grid {
    display: grid; grid-template-columns: 70px repeat(7, 1fr);
    grid-template-rows: 40px repeat(16, 60px); gap: 1px; background: var(--border);
}
.calendar-header, .time-label { background: var(--sidebar-bg); display: flex; justify-content: center; align-items: center; font-size: 0.85rem; color: var(--text-dim); }
.grid-cell { background: var(--grid-bg); position: relative; }

.event-block {
    position: absolute; left: 2px; right: 2px; border-radius: 5px;
    padding: 5px; font-size: 0.75rem; font-weight: 600; z-index: 10;
}
.fixed-event { background: rgba(56, 189, 248, 0.2); border-left: 3px solid var(--accent); color: var(--accent); }
body.light-theme .fixed-event { background: rgba(249, 115, 22, 0.1); border-left: 3px solid #f97316; color: #ea580c; }

/* 리스트 */
.list-container { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1rem; }
.list-item { background: var(--card-bg); padding: 1rem; border-radius: 12px; border: 1px solid var(--border); display: flex; justify-content: space-between; align-items: center; }
.delete-btn { color: #ef4444; background: transparent; border: none; cursor: pointer; }
.edit-btn { color: var(--accent); background: transparent; border: none; cursor: pointer; margin-right: 10px; }

/* 반응형 */
@media (max-width: 768px) {
    #app { flex-direction: column; }
    .sidebar { width: 100%; padding: 0.5rem 1rem; flex-direction: row; border-right: none; border-bottom: 1px solid var(--border); }
    .logo { margin-bottom: 0; font-size: 1.2rem; }
    nav ul { display: flex; gap: 5px; }
    .nav-item { padding: 0.5rem; font-size: 0.8rem; }
    .content { padding: 1rem; }
    .time-input-row { grid-template-columns: 1fr; }
}