/* =============================================
   Tuan Duc Chu — Portfolio
   Royal Navy & Gold · Sidebar layout · Playfair + Source Serif
   ============================================= */

/* --- Royal Navy & Gold Palette --- */
:root {
  --navy-deep:    #05111f;
  --navy-mid:     #0a1e35;
  --navy-border:  #112844;
  --navy-accent:  #1a4a8a;
  --steel:        #4a7ab5;
  --gold:         #b8941e;
  --gold-light:   #d4aa3a;
  --gold-bright:  #f0c84a;
  --sidebar-text: #c8d8ee;
  --sidebar-mute: #6a90bb;
  --bg:           #f0f3f8;
  --surface:      #ffffff;
  --text-dark:    #0d1b2a;
  --text-mid:     #2c3e55;
  --text-mute:    #5a6e85;
  --rule:         #d0d9e8;
}

/* --- Reset --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

/* --- Body & Layout --- */
body {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: 19.5px;
  line-height: 1.8;
  background-color: var(--bg);
  color: var(--text-dark);
  display: flex;
  min-height: 100vh;
}

/* =============================================
   SIDEBAR
   ============================================= */
#sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: 450px;
  height: 100vh;
  background: var(--navy-deep);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 40px 28px 36px;
  overflow-y: auto;
  z-index: 100;
  border-right: 1px solid var(--navy-border);
}

/* --- Photo --- */
#photo-slot {
  width: 140px;
  height: 140px;
  border-radius: 6px;
  overflow: hidden;
  border: 2px solid var(--gold);
  margin-bottom: 18px;
  flex-shrink: 0;
}

#photo-slot img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

#photo-placeholder {
  display: flex;
  width: 100%;
  height: 100%;
  align-items: center;
  justify-content: center;
  background: var(--navy-mid);
  color: var(--sidebar-mute);
  font-size: 0.98rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* --- Sidebar Name & Sub --- */
#sidebar-name {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1.4rem;
  font-weight: 600;
  color: #fff;
  text-align: center;
  line-height: 1.3;
  margin-bottom: 8px;
}

#sidebar-sub {
  font-size: 1.0rem;
  color: var(--sidebar-mute);
  text-align: center;
  line-height: 1.6;
  margin-bottom: 28px;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

/* --- Nav --- */
#sidebar-nav {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin-bottom: 32px;
}

#sidebar-nav a {
  display: block;
  font-size: 1.1rem;
  color: var(--sidebar-text);
  text-decoration: none;
  padding: 8px 14px;
  border-radius: 4px;
  letter-spacing: 0.02em;
  transition: background 0.18s, color 0.18s, padding-left 0.18s;
  border-left: 2px solid transparent;
}

#sidebar-nav a:hover {
  background: var(--navy-mid);
  color: var(--gold-bright);
  padding-left: 18px;
}

#sidebar-nav a.active {
  background: var(--navy-mid);
  color: var(--gold-bright);
  border-left: 2px solid var(--gold-bright);
  padding-left: 18px;
}

/* --- Contact --- */
#sidebar-contact {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 6px;
  border-top: 1px solid var(--navy-border);
  padding-top: 22px;
  margin-top: auto;
}

#sidebar-contact a,
#sidebar-contact span {
  font-size: 1.0rem;
  color: var(--sidebar-mute);
  text-decoration: none;
  text-align: center;
  display: block;
  word-break: break-all;
}

#sidebar-contact a:hover {
  color: var(--gold-light);
}

/* =============================================
   MAIN CONTENT
   ============================================= */
#main {
  margin-left: 450px;
  flex: 1;
  width: calc(100% - 450px);
  max-width: none;
  padding: 60px 72px 100px;
}

/* --- Main centered photo --- */
#main-photo-wrap {
  display: flex;
  justify-content: center;
  margin-bottom: 48px;
}

#main-photo-slot {
  width: 280px;
  height: 280px;
  border-radius: 50%;
  overflow: hidden;
  border: 5px solid #c0392b;
  box-shadow: 0 0 0 3px #e8d5d3, 0 8px 32px rgba(192, 57, 43, 0.18);
  flex-shrink: 0;
}

#main-photo-slot img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

#main-photo-ph {
  display: flex;
  width: 100%;
  height: 100%;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  color: var(--text-mute);
  font-size: 1rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* --- Section Headings --- */
section {
  margin-bottom: 8px;
}

section h2 {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1.45rem;
  font-weight: 600;
  color: var(--navy-accent);
  letter-spacing: 0.04em;
  margin-bottom: 18px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--rule);
}

/* --- HR --- */
hr {
  border: none;
  border-top: 1px solid var(--rule);
  margin: 36px 0;
}

/* --- Paragraphs --- */
p {
  font-size: 1.2rem;
  color: var(--text-mid);
  margin-bottom: 12px;
  line-height: 1.8;
}

/* --- Entry --- */
.entry {
  margin-bottom: 20px;
}

.entry-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 4px;
  margin-bottom: 2px;
}

.entry-title {
  font-size: 1.2rem;
  font-weight: 400;
  color: var(--text-dark);
}

.entry-date {
  font-size: 1.08rem;
  color: var(--text-mute);
  white-space: nowrap;
}

.entry-org {
  font-style: italic;
  font-size: 1.12rem;
  color: var(--steel);
  margin-bottom: 6px;
}

p.entry-desc {
  font-size: 1.13rem;
  color: var(--text-mute);
  font-style: italic;
  margin-bottom: 8px;
  margin-top: 2px;
}

/* --- Lists --- */
ul {
  padding-left: 22px;
  margin-bottom: 8px;
}

ul li {
  font-size: 1.17rem;
  color: var(--text-mid);
  margin-bottom: 5px;
  line-height: 1.7;
}

ul.project-bullets li {
  font-style: italic;
  color: var(--text-mute);
}

/* --- Project Categories --- */
.project-category {
  font-size: 0.98rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--navy-accent);
  font-weight: 600;
  margin-bottom: 14px;
}

.project-category-sub {
  font-size: 0.94rem;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text-mute);
  font-style: italic;
  margin-bottom: 10px;
}

/* --- Skills Table --- */
.skills-table {
  border-collapse: collapse;
  width: 100%;
  font-size: 1.17rem;
}

.skills-table td {
  padding: 5px 0;
  vertical-align: top;
}

.skills-table td:first-child {
  width: 240px;
  color: var(--text-mute);
  font-style: italic;
  padding-right: 20px;
}

/* --- Course Codes --- */
span.code {
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.98rem;
  color: var(--steel);
  margin-right: 7px;
  letter-spacing: 0.02em;
}

/* --- Courses Grid --- */
.courses-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px 32px;
}

.course-col-title {
  font-size: 1.0rem;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--navy-accent);
  margin-bottom: 10px;
  font-style: normal;
}

.course-col ul {
  padding-left: 0;
  list-style: none;
  margin-bottom: 0;
}

.course-col ul li {
  font-size: 1.1rem;
  margin-bottom: 4px;
  color: var(--text-mid);
}

/* --- Links --- */
a {
  color: var(--navy-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

a:hover {
  color: var(--gold);
}

/* --- Footer --- */
footer {
  margin-top: 48px;
  padding-top: 20px;
  padding-bottom: 400px;
  border-top: 1px solid var(--rule);
  font-size: 1.02rem;
  color: var(--text-mute);
}

/* =============================================
   RESPONSIVE
   ============================================= */

/* --- Tablet landscape (900px–1200px) --- */
@media (max-width: 1200px) {
  #sidebar {
    width: 340px;
  }
  #main {
    margin-left: 340px;
    width: calc(100% - 340px);
    padding: 50px 48px 100px;
  }
}

/* --- Tablet portrait (600px–900px) --- */
@media (max-width: 900px) {
  body {
    flex-direction: column;
  }

  #sidebar {
    position: relative;
    width: 100%;
    height: auto;
    flex-direction: column;
    align-items: center;
    padding: 32px 24px 24px;
  }

  #sidebar-nav {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    gap: 4px;
    margin-bottom: 16px;
  }

  #sidebar-nav a {
    padding: 6px 12px;
    font-size: 0.9rem;
  }

  #sidebar-contact {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    margin-top: 0;
    border-top: none;
    padding-top: 0;
  }

  #main {
    margin-left: 0;
    width: 100%;
    padding: 40px 32px 80px;
  }

  #main-photo-wrap {
    margin-bottom: 32px;
  }

  #main-photo-slot {
    width: 200px;
    height: 200px;
  }

  .courses-grid {
    grid-template-columns: 1fr 1fr;
  }
}

/* --- Mobile (max 600px) --- */
@media (max-width: 600px) {
  #sidebar {
    padding: 24px 16px 16px;
  }

  #sidebar-name {
    font-size: 1.1rem;
  }

  #sidebar-sub {
    font-size: 0.78rem;
  }

  #sidebar-nav a {
    font-size: 0.82rem;
    padding: 5px 10px;
  }

  #main {
    padding: 28px 18px 60px;
  }

  #main-photo-slot {
    width: 160px;
    height: 160px;
  }

  section h2 {
    font-size: 1.15rem;
  }

  .entry-header {
    flex-direction: column;
  }

  .entry-title {
    font-size: 0.97rem;
  }

  .courses-grid {
    grid-template-columns: 1fr;
  }

  .skills-table td:first-child {
    width: 140px;
  }
}